GOROC POSITION PAPER ON IGBT FOR CERVICAL CANCER FACULTY OF RADIATION ONCOLOGY THE ROYAL AUSTRALIAN AND NEW ZEALAND COLLEGE OF RADIOLOGISTS

Transcription

1 GOROC POSITION PAPER ON IGBT FOR CERVICAL CANCER FACULTY OF RADIATION ONCOLOGY THE ROYAL AUSTRALIAN AND NEW ZEALAND COLLEGE OF RADIOLOGISTS

2 Name of document and version: Gynaecology Oncology Radiation Oncology Collaborative (GOROC) Position Paper on Image Guided Brachytherapy (IGBT) for Cervical Cancer, Version 1.0 Approved by: Faculty of Radiation Oncology Date of approval: 21 July 2017 ABN Copyright for this publication rests with The Royal Australian and New Zealand College of Radiologists The Royal Australian and New Zealand College of Radiologists Level 9, 51 Druitt Street Sydney NSW 2000, Australia Website: Telephone: Facsimile: Disclaimer: The information provided in this document is of a general nature only and is not intended as a substitute for medical or legal advice. It is designed to support, not replace, the relationship that exists between a patient and his/her doctor.

3 Document name Description Created By Date Created 2017 Maintained By Gynaecology Oncology Radiation Oncology Collaborative (GOROC) Position Paper on Image Guided Brachytherapy (IGBT) for Cervical Cancer This position paper summarises the survey of current practice of IGBT in Australasia, provides evidence to support its use, and makes recommendations on equipment, dose, prescription, dose specification, does reporting and techniques. Training requirements and competency assessments for IGBT are outline, and strategies to implement good IGBT practice are suggested. Gynaecology Oncology Radiation Oncology Collaborative (GOROC) Faculty of Radiation Oncology Version Number Modifications Made Date Modified 1.0 Document published July 2017 Page ii

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5 TABLE OF CONTENTS 1. Introduction Survey of Current Practice of Image Guided Brachytherapy for Cervical Cancer (IGBTCC) Evidence Supporting the Use of IGBTCC Recommendations on Equipment, Dose, Prescription, Dose Specification, Dose Reporting and Techniques Training Requirements and Competency Assessment Implementing Good IGBTCC Principles Summary Acknowledgements Comments and Review References Page iv

6 About the College The Royal Australian and New Zealand College of Radiologists (RANZCR) is a not-for-profit association of members who deliver skills, knowledge, insight, time and commitments to promote the science and practice of the medical specialties of clinical radiology (diagnostic and interventional) and radiation oncology in Australia and New Zealand. The Faculty of Radiation Oncology, RANZCR, is the peak bi-national body advancing patient care and the specialty of radiation oncology through setting of quality standards, producing excellent radiation oncology specialists, and driving research, innovation and collaboration in the treatment of cancer. Our Vision RANZCR as the peak group driving best practice in clinical radiology and radiation oncology for the benefit of our patients. Our Mission To drive the appropriate, proper and safe use of radiological and radiation oncological medical services for optimum health outcomes by leading, training and sustaining our professionals. Our Values Commitment to Best Practice Exemplified through an evidence-based culture, a focus on patient outcomes and equity of access to high quality care; an attitude of compassion and empathy. Acting with Integrity Exemplified through an ethical approach: doing what is right, not what is expedient; a forward thinking and collaborative attitude and patient-centric focus. Accountability Exemplified through strong leadership that is accountable to members; patient engagement at professional and organisational levels. Code of Ethics The Code defines the values and principles that underpin the best practice of clinical radiology and radiation oncology and makes explicit the standards of ethical conduct the College expects of its members. Page v

7 1. INTRODUCTION The standard of management for patients diagnosed with locally advanced cervix cancer is combined external beam radiotherapy (EBRT) with concurrent cisplatin chemotherapy, followed by cervical brachytherapy. Major advances in planning, prescription and delivery of EBRT has resulted in routine use of cross-sectional imaging and three-dimensional (3D) conformal beam radiotherapy treatment delivery and/or intensity modulated radiotherapy (IMRT) in routine practice. Similarly, 3D image guided brachytherapy for cervical cancer (IGBTCC) has allowed for more accurate definition of the clinical target volume (CTV) and organs at risk (OAR), precise definition of normal tissue dosimetry, accurate verification of applicator position, ability to conform a high dose to the CTV and lower dose to OAR, as well as potential for dose escalation. The purpose of this paper is to provide a position statement from FRO on the use of IGBTCC. Since the 2010 publication of the Faculty of Radiation Oncology (FRO) position paper on IGRT, there have been several publications in this area bringing IGRT into standard general practice [1-3]. This paper provides a background to current practice in cervical brachytherapy in Australasia, summarises the international guidelines [4-7] on the safe and effective implementation of IGBTCC, and provides recommendation for contemporary practice. 2. SURVEY OF CURRENT PRACTICE OF IMAGE GUIDED BRACHYTHERAPY FOR CERVICAL CANCER (IGBTCC) The previous survey in 2009 identified twenty centres providing cervical brachytherapy in Australia and New Zealand [8]. There was high level of use of 3D imaging and awareness of Groupe European de Curietherapie of the European Society for Therapeutic Radiology and Oncology (GEC-ESTRO) recommendations. At that time, 65% of departments were using 3D computer tomography (3D CT) to plan brachytherapy insertions. However, only four centres (20%) were contouring, prescribing and reporting treatment according to GEC-ESTRO recommendations. A survey was electronically distributed to members of the Australian and New Zealand Gynaecology Oncology Group (ANZGOG) [9] in 2014/2015 to determine current radiation oncology patterns of practice in relation to cervix cancer. A total of 22 centres reported treating cervical cancers (refer to table 1 following). All states and territories in Australia and both islands in New Zealand were represented in the responses. Centres who did not offer brachytherapy, referred their patients on to centres that did. This highlights that none of these eight centres felt that an external beam boost was sufficient to effectively replace brachytherapy. Importantly, this is favourable in contrast to recently published US Surveillance, Epidemiology and End Results (SEER) data [10], which demonstrates a worrisome trend to decreased brachytherapy usage in their cervical cancer population and associated worse outcomes. Page 1

8 Table 1. Patterns of Practice Survey for brachytherapy for cervix cancer in Australia and New Zealand (adapted from [9]) Number of centres EBRT conformal 21/22 EBRT IMRT/VMAT 13/22 Brachytherapy offered at centre 14/22 HDR 14/14 PDR 1/14 Brachytherapy sent elsewhere 8/22 Brachytherapy Equipment (/14) Tandem/ovoid 13/14 Tandem/vaginal cylinder 12/14 Tandem/ring 4/14 Free-hand interstitial 4/14 Applicator-guided interstitial 4/14 All five applicators 2/14 Brachytherapy Imaging (/14) X-ray 2/14 CT 11/14 US 4/14 MRI 7/14 More than 1 modality 7/14 IGBTCC offered at centre 10/ External beam Radiotherapy (EBRT) The majority of respondents (68%; 15/22 centres) treated more than ten patients per year. Conformal radiotherapy was used by the majority (21/22 centres) when treating the pelvis, though several centres (13/22) also used techniques such as intensity modulated radiotherapy (IMRT), volumetric modified arc therapy (VMAT) or tomotherapy. Accordingly, dose was prescribed to either the ICRU RP or to 95% of PTV, depending on the technique used. The most common EBRT doses used to treat the pelvis +/- para-aortic lymph nodes were Gy in 1.8-2Gy/fraction. 2.2 Brachytherapy All survey respondents have high dose rate (HDR) brachytherapy machines (14/14) and one centre also had a pulsed dose rate (PDR) machine. None of the surveyed centres used low dose rate (LDR) brachytherapy for cervical cancer. Half of the centres started brachytherapy once all the EBRT was completed, the remainder started brachytherapy during weeks four or five of EBRT. The majority (10/14, 71%) aimed to complete treatment within eight weeks, as longer duration of treatment is associated with worse outcome. Most centres used more than one type of brachytherapy applicator. Tandem and ovoid applicators (13/14; 93%) and tandem and vaginal cylinder applicators (12/14; 86%) were the most common. Tandem and ring applicators were available at four centres and free-hand interstitial needles were available at four centres. Only four centres reported having applicator-guided interstitial needle capabilities. Only two centres out of the fourteen reported using all five brachytherapy applicator types, both from New Zealand. Brachytherapy insertion takes place in the operating theatre (9/14; 64%), with the other five centres having a dedicated brachytherapy suite within their radiation oncology department. All centres used a general anaesthetic (GA) for their patients. Spinal and epidural sedation was also used (8/14 and 2/14 Page 2

9 centres respectively). Ultrasound guidance was used to aid in the insertion of applicators in 86% of centres (12/14). 2.3 Brachytherapy Planning Of the 14 centres that offer brachytherapy for cervical cancer, two centres (14%) use plain X-rays for brachytherapy planning, 11 centres (79%) use CT, four centres (29%) use ultrasound and seven centres (50%) use MRI. Seven centres (50%) used more than one imaging modality in their brachytherapy workflow. Contouring of organs at risk (OAR: such as rectum, bladder and sigmoid) was performed in 79-93% of centres. The high risk clinical target volume (CTVHR as defined by the Gynaecological GEC-ESTRO Working Group [11] ) was volumed by six centres (43%), five of which used MRI in their workflow, the remaining centre used CT. Overwhelmingly, brachytherapy plans were optimised based on OAR constraints (13/14 centres; 93%), with CT and/or MRI being used to volume OARs. Only one centre planned based on standard 2D applicator geometry without any further optimisation based on OAR dose constraints. Brachytherapy dose was prescribed to Point A in five centres (36%), CTVHR in six centres (43%), target volumes as defined by local departmental policy in two centres (14%) and Point M in one centre (7%). 2.4 Implementation of IGBTCC There are 10 centres (71%) currently using IGBTCC, with four centres (29%) wanting to implement MRI-guided brachytherapy. Three of these four centres currently use CT in their brachytherapy planning. The most commonly identified obstacles to implementation or improvement of IGBTCC were lack of access to MRI (11 centres, 79%) and insufficient patient numbers (two centres, 14%). Other obstacles cited were lack of CT/MRI applicators, lack of planning software, insufficient staff training, limited access to anaesthetics, time constraints on staff, hospital attitudes and inability to perform insertions in the brachytherapy suite. Marked increased in the use of 3D imaging and awareness of GEC-ESTRO recommendations. Implementation and reporting of IGBTCC is dependent on local resources and infrastructure. 3. EVIDENCE SUPPORTING THE USE OF IGBTCC IGBTCC has been shown to be beneficial for both placement of applicators and in treatment planning and patient outcomes. The benefits include optimal positioning of the applicators, accurate delineation of target volumes and organs at risk. Studies have shown this has resulted in improved local control and reduction in toxicities [12, 13]. 3.1 Image guidance for applicator placement and verification Real-time ultrasound can be used to guide the placement of the intrauterine tandem in the uterine cavity. The benefits of this are improved accuracy [14] and positioning of the tandem and useful aid for difficult insertion [15, 16]. This can result in a reduced need for repeat procedures and reduced risk of uterine perforation, which is a recognised complication of cervical brachytherapy. Optimal placement also aids in better dose delivery to the target volume. Post procedure imaging with CT or MRI though cannot alter applicator placement can aid in modifying treatment. Page 3

10 3.2 Image guidance in treatment planning Historically, planning and dose delivery in cervical brachytherapy was based on dose points. But increasing use of image guidance in the form of ultrasound, CT and MRI for peri and post- operative imaging has shown a positive impact on improving dose coverage of the tumour, while decreasing doses to organs at risk. This has resulted in improved local control and reduced toxicity also showing trends in improving overall survival. Planning studies from various institutions have demonstrated the superiority of improved target dose coverage and reduction in doses to organs at risk with CT/ MRI/USG 3D planning as compared to conventional 2D planning [17-20]. Potter et al. [21] highlighted the use of CT initially and then MRI for brachytherapy planning which improved local control. The reported pelvic control rate was 96% for tumours less than 5cm in diameter and 90% for tumours greater than 5cm, respectively. A subsequent update [22] showed not only continuing improvement in local control but decreasing bowel and bladder toxicity. The results also showed the possibility of a safe dose escalation for the more advanced tumours maintaining the same therapeutic ratio [22]. These results have been replicated in both single-centre and multi-centre environments reporting the use of MR, CT or real-time ultrasound [13, 23-27] for delineating and dose optimisation of cervical brachytherapy. The reported improvements are between 10-30% in survival, almost a two-third reduction in local relapses and decreased toxicities, supporting the use of IGBTCC. These efforts have resulted in the release of the International Commission on Radiation Units and Measurements (ICRU) Report 89, outlining the prescribing, recording and reporting brachytherapy for cervix cancer [28]. IGBTCC has been shown to be beneficial in improving local control of pelvic disease as well as reducing toxicity when used to guide placement and verification of applicators. IGBTCC has improved prescription, treatment planning and dose reporting. 4. RECOMMENDATIONS ON EQUIPMENT, DOSE, PRESCRIPTION, DOSE SPECIFICATION, DOSE REPORTING AND TECHNIQUES The following recommendations were based on the IGBTCC guidelines in the UK [4], the American Brachytherapy Society (ABS) consensus guidelines for locally advanced cancer of cervix [6], the Imaging Strategies for Definitive Intracavitary Brachytherapy for Cervical cancer in Ontario [7] and ICRU 89 Report [28]. 4.1 Equipment HDR is a well-established option for treatment of cervical cancer [29]. HDR and LDR brachytherapy are relatively equivalent in terms of survival outcomes [30]. Advantages of HDR include short treatment times, outpatient treatments, avoidance of exposure to staff, consistent and reproducible applicator positioning and dose optimisation. However, HDR treatment needs to be fractionated, thus impacting on theatre resources (unless using a cervical sleeve). In addition, HDR treatment rooms require considerable shielding which may impact on cost of facilities. PDR has been developed to simulate LDR brachytherapy. There are theoretical radiobiological advantages over HDR. In PDR, single treatment is delivered over two to four days at dose rates of Gy/h [31]. However, there is little data available on efficacy with regards to local control and toxicity. The longer treatment times may also have significant impact on patient throughput and resource requirements. Page 4

11 The principles of IGBT are applicable to both HDR and PDR. The choice of equipment will depend on local resource implications. 4.2 Dose prescription Dose Fractionation Schedules For clinical use, as per the RCR Working Party [4], the concept of the Equivalent Dose in 2Gy fractions (EQD2) is considered the most appropriate dose reporting to understand due to its similarity to EBRT regimes. A useful worksheet to calculate EQD2 for different Dose Fractionation Schedules is available from GEC-ESTRO [32]. This provides theoretical guidance and should not replace the observations or judgements of physicians experienced with HDR and/or PDR brachytherapy. In addition, when using these formulae, it must be remembered that radiobiological assumptions have been used: HDR Schedules α/β ratio is the only radiobiological assumption made PDR Schedules a number of assumptions need to be made which include α/β ratio, halftime for repair of human tissues (T1/2: which is an area of significant uncertainty), the number of pulses, pulse interval and pulse time. A comparison of the EQD2 for some LDR and HDR Dose-Fractionation Schedules is given in tables 2 and 3, below: Table 2. LDR-Point A Determined Implant Total EBRT (Gy) at 1.8Gy/Fx No. LDR fractions LDR Dose per fraction Total LDR Pt A Dose (Gy) Total Pt A Dose (Gyα/β 10) (OUTBACK Trial Protocol [33] ) Table 3. HDR-Point A Determined Implant or Volume Directed Approach Total EBRT (Gy) at 1.8Gy/Fx No. HDR fractions HDR Pt A Dose/fraction (Gy) Total HDR Pt A Dose (Gy) Total EBRT (Gy) at 2Gy/Fx No. HDR fractions HDR Pt A Dose/fraction (Gy) Total HDR Pt A Dose (Gy) (OUTBACK Trial Protocol [33] ) Total Pt A EQD2 (Gyα/β 10) Total Pt A EQD2 (Gyα/β 10) Page 5

12 4.2.2 PDR Schedules Australasian team(s) utilising PDR, use a Dose Rate between Gy/h with an hourly pulse and aim to achieve a combined EQD2 of 80-85Gyα/β10 for a cervical tumour <5cm and 85-90Gyα/β10 for tumours 5cm or greater. In combined EBRT and PDR, the accepted maximum total doses to 2cc 1 in EQD2 for OAR include: Bladder, maximum of 80-90Gy α/β3 Rectum, maximum of 75Gy α/β3 Sigmoid/Bowel, maximum of 75Gy α/β3 When implementing HDR or PDR the use of published Dose-Fractionation Schedules with documented clinical date on outcomes is recommended. 4.3 Dose Specification and Reporting The ICRU 89 [28] provides comprehensive recommendations on prescribing, recording and reporting brachytherapy focusing on volumetric imaging in cervix cancer brachytherapy. Reporting is structured following the level approach previously introduced in ICRU reports: Level 1 describes the minimum requirements, which should be followed in all centres, for all patients, and represents the minimum standard of treatment. Level 1 dose reporting should include TRAK, point A dose, recto-vaginal reference point doses, and D0.1cc and D2cc for the bladder, rectum. Level 2 indicates advanced standards of dose planning and treatment that are based on more comprehensive information. Level 2 includes all items reported in level 1, and additional dose reporting for defined volumes (D98%, D90%, D50% for the CTVHR, D98% for the GTVres, D98% for the pathological nodes; and OARs (bladder reference point dose, and D0.1cc and D2cc for the sigmoid, D2cc for the bowel, vaginal point doses at level of sources, and other bladder, rectum and vaginal doses). D90% is defined as minimum dose to 90% of tumour target volume, Gyα/β10 for CTVHR, and D2cc as minimum dose to the most exposed 2cc of OAR, Gyα/β3 for bladder, rectum and bowel. Level 3 describes new forms of planning and treatment largely related to research and development for which reporting criteria cannot yet be established. Level 3 includes all items reported in level 1 and 2, and absorbed-dose reporting for the tumour, OAR volumes and points and dose-volume reporting for OARs as well as isodose surface volumes (85 Gy EQD2 and 60 Gy EQD2 volumes). The reporting of the physical dose and EQD2 to Point A, the D90 and V100 for the CTV HR, and the D2cc for OAR, is the minimum requirement for IGBTCC. 1 For this position paper, cc will be used instead of cm 3. Page 6

13 4.4 Dose targets and constraints The RCR Working Party [4] and the international study on MRI-guided brachytherapy in locally advanced cervical cancer (EMBRACE II) [34] recommended the following dose targets and constraints: Table 4. Guidelines for dose targets and OAR RCR [4] EMBRACE II [34] EQD2 Pt A Gy α/β10 >65 Gy α/β10 D90 CTV HR Gy α/β Gy α/β10 Bladder D2cc Gy α/β Gy α/β3 Rectum D2cc Gy α/β Gy α/β3 Sigmoid D2cc Gy α/β Gy α/β3 Bowel D2cc Gy α/β Gy α/β3 GEC-ESTRO and ABS recommend tumour EQD2 of Gy α/β10 particularly for those with residual disease measuring 4cm at time of brachytherapy which is higher than doses traditionally delivered in the UK and Australia and New Zealand. When delivering these higher doses, there must be detailed attention to OAR doses and close monitoring of toxicity rates. With addition of interstitial BT to intracavitary BT, there is a paucity of data from which to formulate recommendations regarding standardising the number of implant procedures and number of fractions per implant. Although the ABS have provided BT Dose schedules based on reports in the literature and their panels experience [6], the primary use of interstitial BT in Australasia is to manipulate the D90 and OAR 2cc doses without alteration of the standard fractionation schedules used for intracavitary BT. In general, approximately 10-20% of total dwell times are linked to source positions in the interstitial needles, and most of the dose should be delivered through the tandem and ring or tandem and ovoids. The minimum EQD2 to Point A and/or D90 should be 75-80Gy α/β 10. Dose escalation to 85-90Gy α/β 10 with MRI-based IGBT is recommended as soon as is reasonably achievable with close attention to not exceed dose constraints of OAR. 4.5 Technique Imaging Appropriate imaging is critical throughout the treatment chain for brachytherapy of the cervical cancer. The different stages where imaging is necessary include guidance for applicator placement and verification of immobilisation, contouring of target volumes and OARs, and geometric reconstruction of the applicators. Clinical drawings have traditionally been used to describe the extend of disease based on clinical examination. Tumour that is visible or palpable is drawn manually, on paper templates. With the advent of IGBTCC, an argument can be made to also include disease findings from imaging examinations into these clinical drawings. Transabdominal ultrasonography should be considered for use to guide the placement of the intra-uterine applicator intra-operatively and limit perforations [35]. Computed tomography versus MRI-based contouring for tumour and OAR was reported in a prospective trial [36]. There were no differences in OAR volumes and dose but CT was found to overestimate tumour size with an associated reduction in D90 (or could lead to increased OAR dose if an attempt to optimise D90 was made). Furthermore, CT could not differentiate GTV from CTV or apex of cervix from uterine Page 7

14 tissue although considered less clinically relevant if treating to CTVHR when the GTV is expected to receive a higher dose Clinical results suggest MRI is superior to CT in allowing dose optimisation and/or escalation thus MRI based IGBTCC is the gold standard achieving superior local control rates and lower toxicity rates, particularly for large tumours [12]. Computed tomography based techniques have provided excellent local control rates for small tumours (2-5cm) [37], presumed on basis that the risk of geographical miss is minimal and dose escalation is unlikely to be required. Ultrasonography is an accessible and economical imaging modality. It has been utilised to guide cervical intracavitary planning and has been shown to offer comparable anatomical detail to 2D MRI to allow sufficient dose to be delivered to the target area while sparing normal surrounding tissues. There is acknowledgement of some limitations particularly the need for appropriate training and education which, when overcome, can provide an alternative and economical imaging modality option for planning in any brachytherapy program [35, 38] Applicator Design A modelling study favours dwells close to cervix and vaginal surface, similar to a ring applicator configuration rather than ovoids [39]. Dose optimisation with tandem-ovoid applicators results in improved tumour target coverage and/or reduced dose to OAR, likely to result in improvements in local control and toxicity [40]. Therefore, both tandem-ring and tandem-ovoid applicators are suitable for delivery of IGBTCC. The addition of interstitial BT to intracavitary further improves tumour coverage for those with insufficient response and/or unfavourable topography after EBRT while limiting the dose to OAR [41] Interstitial Brachytherapy in IGBTCC Guidelines from the ABS [5] recommend HDR interstitial brachytherapy for cervical cancer patients with unfavourable topography after EBRT such as patient with a bulky cervical lesion (>4cm),or a narrow vaginal apex, or inability to enter the cervical os, or extension to the lateral parametria or pelvic sidewall, or lower vaginal extension. Principles of IGBT are applicable to both tandem-ring and tandem-ovoid applicators; tumours with unfavourable topography after EBRT should be considered for interstitial BT. 5. TRAINING REQUIREMENTS AND COMPETENCY ASSESSMENT 5.1 Training Requirements The implementation of IGBTCC cancer represents a departure from standard practice using 2D imaging, which has been the practice in many departments for many years. It is therefore important this development is carried out in a safe environment. The following training steps have been recommended by the UK guidelines [4] Target volume delineation Even though RO have reasonable experience in sectional anatomy with CT, it is advantageous to have assistance of a MRI radiologist when contouring the CTV and OAR [42]. It is essential training in departments where the radiation oncology medical physicist (ROMP) or radiation therapist (RT) take central role in volume contouring. In addition, teaching courses and practical workshops, which are organised annually by ESTRO and ABS, should be attended by the entire Page 8

15 brachytherapy team as these courses are excellent resources for their preparedness to implement IGBTCC Applicator reconstruction (CT and/or MRI) In IGBT the geometry of the applicator is extracted from the patient s 3D images and introduced into the planning system, this process is identified as applicator reconstruction [43]. Training must take place for applicator commissioning and reconstruction methods to be implemented appropriately to minimise uncertainties and avoid unnecessary errors Dose evaluation The dose distribution from IGBTCC plan is often evaluated by visual inspection of the isodoses with respect to the OAR and CTVHR, CTVIR. The final decision on a treatment plan always included a detailed analysis of the dose volume histograms (DVH) for CTVs and OAR, taking into account the whole treatment course, including external beam radiotherapy (EBRT) [44]. The volumes and D90% of the CTVHR, as well as the D2cc of OAR should be included in the IGBTCC technique. Total doses, including EBRT and the values for each individual brachytherapy fraction, are biologically normalised to conventional 2Gy per fractions (α/β= 10Gy for target, and α/β= 3Gy for OAR). Familiarisation and training in dose evaluation are essential Dose Modification Dose optimisation involves manipulation of dwell positions and dwell times. Non-optimised dose distributions in cervical brachytherapy result in highly variable tumour doses. Conversely, the combined use of IGBTCC and dose optimisation significantly improve the volume that can be effectively treated to 85Gy (α/β=10) [21, 45]. Thus, training in dose modification is also an integral component of implementing a successful IGBTCC program Quality assurance For departments taking up IGBTCC, various amounts of brachytherapy experiences are likely to be encountered. It is therefore essential for such a complex procedure as IGBTCC that the brachytherapy team acquires a competent level of experience and training in all aspects of clinical and physics items to be appropriately implemented into clinical practice [46]. Cancer Care Ontario [47] has also made further recommendations to standard personnel required for IGBT program including ROs, ROMPs, RTs, anaesthetists and nurses with experience in BT; as well as individuals with key expertise in the area of MRI. These include MRI pelvic radiologist, MRI technologist and MR physicist. CCO similarly recommends training opportunities should be provided to all personnel involved in the BT program. Cross-training is also recommended for RT interacting with MRI technicians in the simulation capacity of the MR suite. Likewise, MR technicians also need to understand the brachytherapy process so that imaging decisions can be made in an informed and appropriate manner. To ensure safe practice of IGBTCC, staff training is essential in critical areas including target volume definition, applicator reconstruction, dose evaluation and modification and quality assurance. 5.2 Competency assessment The Royal College of Physicians and Surgeons of Canada [48] has set specific competencies acquired to perform brachytherapy upon completion of training in radiation oncology. These include identifying indications for the use of brachytherapy, applying basic principles of physics and radiobiology to develop a safe and effective brachytherapy treatment plan, using appropriate imaging modalities to guide insertion and placement of radioactive sources, performing brachytherapy in a sterile environment and Page 9

16 with appropriate radiation safety precautions, managing the medical care of patients during and after brachytherapy treatment, and critically evaluating brachytherapy implant quality. RANZCR currently does not have any set criteria for a RO to practice brachytherapy. Suggested forms of accreditation may include: membership of a brachytherapy organisation (e.g. ABS, ABG, GOROC, etc.) attendance at relevant training courses and brachytherapy conferences regular attendance of Gynaecological oncology MDT evidence of ongoing professional development documented case-load in logbook involvement in departmental brachytherapy QA audit clinical audit of tumour control and toxicity outcomes, or participation in mandatory training in brachytherapy emergency procedures. The Australasian College of Physical Scientists and Engineers in Medicine (ACPSEM) [49] has also set guidelines on assessing competence for ROMP to participate in brachytherapy. For RT, there are no competency requirements for brachytherapy program. The Royal Brisbane and Women s Hospital Cancer Care services [50] have implemented competencies required by RT to participate in their brachytherapy treatment program. The topics covered include basic physics principles of HDR and sources, design principles and operation of HDR system, radiation safety and protection, daily QA test on HDR system, insertion of applicators/catheters, HDR treatment planning and HDR treatment. In general, specific tools designed to assess competency in IGBTCC are currently lacking and developments in this area are under way. An international study on MRI-guided brachytherapy in locally advanced cervical cancer (EMBRACE) has reported on quality assurance in MR image guided adaptive brachytherapy for cervical cancer [46]. Clinical evaluation items include accuracy of tumour size reporting at diagnosis and at BT, contouring of tumour and target (CTVHR and CTVIR for BT), contouring of OARs. Brachytherapy physics evaluation items include applicator reconstruction, dose reporting via points and DVHs and optimisation. Specific tools to assess competency in IGBTCC are lacking. Established guidelines and practice standards should be followed and desirable accreditation activities should be developed and maintained. Assessment should be directed to the entire multidisciplinary brachytherapy team (RO, ROMP, RT). Page 10

17 6. IMPLEMENTING GOOD IGBTCC PRINCIPLES The evidence for image-guided brachytherapy process has been previously outlined. The benefits of improved local control and reduced toxicity compel a strong case for implementing good image-guided brachytherapy process in an existing or new centre performing cervical brachytherapy. The group is however mindful of the limitation of resources that is involved in implementing such a program. Table 5 is adapted from the RCR [4] and summarises the minimum resources requirements to achieve the benefits of IGBT in Australia and New Zealand. Table 5. Minimum requirements to achieve benefit of IGBT BENEFIT MINIMUM RESOURCES REQUIRED Equipment Imaging Applicator Additional training I. Applicator placement & Any US Any Minor verification II. OARs delineation and Any CT Any Minor doses III. Conformal dose distribution HDR/PDR CT Any Yes (major) IV. Safe Dose escalation HDR/PDR MRI MR compatible Yes (major) Departments considering IGBT can decide the level of implementation based on the resources that are available to them. Based on the above considerations, most if not all departments will have the resources to implement Level I and II. Most departments should be able to fulfil the requirements of Level III with additional training. Implementation for Level IV benefit may only be successful in few centres due to the need for MRI imaging. Dose escalation with MRI-based IGBT leads to improved local control without increasing toxicity and should be implemented as soon as reasonably achievable. The most common obstacles identified in Australasian departments were lack of access to MRI and insufficient patient numbers [8]. The Cancer Care Ontario Imaging strategies [7] may give some alternatives for centres that have limited MRI access. As the use of MRI is limited through local access and funding, it will be necessary for departments to develop local protocols using available imaging modalities (with clinical drawings, U/S and/or CT) to ensure safe and effective IGBTCC treatment. The question of whether cervical brachytherapy caseload affecting quality remains controversial. Thompson et al. [51] reported on patterns of care of BT in NSW, and found cervical BT treatment depends on caseload. The higher caseload departments (treating at least 10 patients per year) were more likely to complete treatment within desirable time of less than eight weeks, and likely to treat to point A doses of more than 80Gy. Overall treatment time longer than seven weeks and increasing CTVHR volume have been found to be associated with lower local control in the retroembrace study [52]. Even though these data cannot prove a relationship between institutional volumes and outcomes in the setting of IGBTCC, radiation oncologists should be aware of a potential risk associated with low-volume treatments. Page 11

18 7. SUMMARY In the era of modern radiotherapy practice, image-guided brachytherapy in cervical cancer (IGBTCC) is strongly recommended, and is a practice that all individual departments should pursue. Evidence suggests that effective and safe delivery of IGBTCC leads to improved local control and reduced toxicity. The improvement in clinical outcome is likely to result from accurate definition of the CTVs and OAR, precise definition of normal tissue dosimetry, accurate verification of applicator position, ability to conform high dose to CTV and OAR, and potential for dose escalation. Departments should review recommendations and guidelines, source suitable equipment, assess available imaging modalities, recruit appropriate staff at each facility, undertake staff training in a multidisciplinary context (including RO, ROMP, RT and nurses), and implement a stringent quality assurance program to deliver a successful and safe IGBTCC. ACKNOWLEDGEMENTS This position paper was developed by the Gynaecology Oncology Radiation Oncology Collaborative Working Group: Dr Viet Do (Chair), Dr Susan Brooks, Dr David Byram, Dr Philip Chan, Dr Jennifer Chard, Dr Raphael Chee, Dr Rebecca Chin, Dr Geetha Govindarajulu, Dr Braden Higgs, A/Prof Michael Jackson, Dr Lisa Johansson, Dr Pearly Khaw, Dr Carminia Lapuz, Dr Karen Lim, Dr Chelsie O'Connor, Dr Serena Sia, and Dr Stephen Thompson. This position paper was also reviewed by the Australasian Brachytherapy Group, chaired by A/Prof Michael Jackson, and significant contribution from Sylvia van Dyk and Emily Flower. No funding or conflicts of interest are declared. COMMENTS AND REVIEW The Faculty of Radiation Oncology aims to review professional documents within three years of the date of approval. If you have any comments or feedback to be considered at the next review, please faculty@ranzcr.edu.au Page 12

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22 NOTES Page 16

23 THE ROYAL AUSTRALIAN AND NEW ZEALAND COLLEGE OF RADIOLOGISTS