INTRAOPERATIVE IRRADIATION: A PRIMER FOR THE COMMUNITY ONCOLOGY TEAM Conflicts of Interest Yes, we did have a latte; don t own stock
Acknowledgements Jonathan Ashman (Mayo Scottsdale) Rodney Ellis (Case Western) Len Gunderson (Mayo Scottsdale) Dorothy Hargrove (OHSU) Michael Haddock (Mayo) Ed Kim (UW) Susha Pillai (OHSU) Timur Mitin (OHSU) Learning Objectives Explain the rationale for use of IORT as a component of therapy for malignant disease Describe indications for IORT as a component of therapy Describe the current state of evidence supporting use of IORT and remaining knowledge gaps Objectives are to Review Basics of IORT IOERT = Intraoperative Radiation Therapy Patient selection Normal tissue tolerance Method/logistics of treatment Results
Intraoperative Radiation Therapy Rationale Radiation treatment given to a tumor or tumor bed during open surgery Limits dose to normal tissues by: Moving them out of the way Using electron beams or brachytherapy sources (i.e. Ir-192) that penetrate only 2-5 cm Allows additional radiation treatment not otherwise possible IORT Patient Selection Criterion Surgery alone will not achieve acceptable local control [ie, res (m)] External beam dose aim 60-70 Gy for curative attempt IORT will be performed at the time of a planned operative procedure IORT plus EBRT technique would theoretically result in a more suitable therapeutic ratio between cure and complications IOERT vs HDR-IORT boost - which is technically more feasible No evidence of DM or PS Rare exceptions: Resectable solitary metastasis, excellent chemotherapy options, or slow progression of systemic disease IOERT Plus EBRT Mayo Clinic Irradiation Factors External beam (dependent on organ tolerance) 45-50.4 Gy/25-28 fx/5-5.5 wks IORT (dependent on degree of resection, EBRT dose) Narrow margin, R0 resection 10 Gy Micro residual, R1 resection 10-12.5 Gy Gross residual, R2 resection 15-17.5 Gy Unresectable 20 Gy Which Patients Should be Considered for IORT? Locally advanced Head and Neck Locally advanced rectal/recurrent rectal Borderline resectable pancreas Retroperitoneal > Extremity Sarcomas Locally advanced cervix/endometrial cancers Breast patients (although we will not treat this population with Mobetron @ OHSU, as our breast surgeons prefer the Intrabeam approach)
Which Patients Should be Considered for IORT? Locally advanced rectal/recurrent rectal Which Patients Should be Considered for IORT? NCCN Guidelines version 2.2015 www.nccn.org Which Patients Should be Considered for IOERT? One RCT French study, 142 patients with T3-4, or N1, preop radiation, TME randomized to +/-IORT No difference in OS, DFS, LC (91.8 v 92.8%) Most recent systematic review/meta analysis 2011 29 studies, 3003 patients OS, DFS, LC favored IORT Three North American single institutional studies MGH, MDACC, Mayo Dubois et al. Radiotherapy and Oncology 2011;98:298-303 Chang et al. Surgical Oncology 2013;22:22-35
Locally advanced rectal cancer (MGH) 73 patients with gross or FS pos margins received IORT Complete resection 5-yr local control 89% 5-yr DFS 63% Residual disease 5-yr local control 65% 5-yr DFS 32% 1981-2008, 607 patients 5-yr local control R0 resection 46% R1 resection 27% R2 resection 16% Grade 3 toxicity 11%, most common AE was neuropathy (11%) Locally advanced rectal cancer (Mayo) Nakfoor BM, et al. Ann Surg 1998;228:194 200 Haddock MG et al. International Journal of Radiation Oncology Biology Physics. 2011;79:143-150 Locally advanced rectal cancer (Mayo) Locally advanced rectal cancer (MDACC) 1981-2008, 607 patients 5-yr local control R0 resection 46% R1 resection 27% R2 resection 16% Risk of systemic failure is higher than risk of local failure 100 patients, 30 primary/70 recurrent 5-yr LR/OS Primary 94% / 61% Recurrent 60% / 56% 5-yr local recurrence R0 72% R1 60% Haddock MG et al. International Journal of Radiation Oncology Biology Physics. 2011;79:143-150 Hyngstrom JR et al. Journal of Surgical Oncology 2014;10 9:652 658
Retroperitoneal Sarcoma Retroperitoneal Sarcoma Local recurrence rate > 50% NCI phase III trial (Sindelar et al., Arch Surg 1993): 20 Gy IOERT with 35-40 Gy post-op EBRT better than 50-55 post-op EBRT alone Local recurrence 80% in surgery+ EBRT OS 40% in surgery + IOERT + EBRT (p<0.01) Retroperitoneal Sarcoma NCCN Guidelines version 1.2015 Retroperitoneal Sarcoma 1996 2011, 63 patients, Mayo (AZ) Pre-op EBRT 45 50 Gy IOERT to any close or high-risk margin Mobetron, 10 to 20 Gy based on EBRT dose and amount of residual disease IOERT applicator size included the targeted at-risk portion of the tumor bed with a 1 cm margin Stucky, et al., Journal of Surgical Oncology, 2014
Retroperitoneal Sarcoma Pancreas (Mayo Scottsdale) -48 pt cohort rec d preop CRT -31 pts underwent laparotomy -original unresect N=20 - -original borderline N=11-16 pts underwent GTR -R0 N=11; R1 N=5-28/31 pts rec d IOERT (Mobetron), 1-cm margin (i.e. 4 cm tumor bed = 6 cm applicator) R0 resection, 12.5 Gy R1 resection, 12.5 Gy R2 resection, 15 Gy Unresectable, 17.5 Gy (N=2), 20 Gy (N=12) Intraoperative Radiation Therapy Rationale Radiation treatment given to a tumor or tumor bed during open surgery Limits dose to normal tissues by: Moving them out of the way Using electron beams that penetrate only 2-5 cm Allows additional radiation treatment not otherwise possible IORT Treatment Facilities and Technology Dedicated IORT facilities In OR setting In radiation oncology Mobile IORT units IOERT (Mobetron, Novac-7) HDR-IORT brachytherapy
IORT Treatment Facilities and Technology HDR-IORT brachytherapy IORT Advantages of catheter-based IORT Narrow cavities Steeply sloping surfaces Areas where treatment delivery demands turning a corner Anatomic site examples where HDR or LDR catheterbased intraoperative brachytherapy is preferred: -skull base -paranasal sinuses -diaphragm -deep, narrow pelvis pelvis -retropubic area After completion of surgical resection an IORT applicator is placed over the tumor bed and attach to the table using a modified Bookwalter clamp Intraoperative High Dose Rate Brachytherapy (IOHDR) Able to deliver high surface dose to areas not amenable to IORT with electron Can conform and optimize dose as needed if desired Requires a shielded OR facility and may require extended treatment time depending on the field size and source activity
TRANSPORTATION TO O.R. HDR Unit Transport Cart Close margins ETHMOID SINUS IOHDR ethmoid sinus MEMORY CARD
IOHDR TREATMENT IOHDR REMOTE MONITORING VIDEO HDR UNIT TRANSFER CABLES RADIATION THERAPIST RECTUM ANESTHESIA MONITOR foam template silicon delrin FLEXIBLE IOHDR APPLICATOR IOHDR APPLICATORS
APPLICATOR IN PELVIS IOERT Electron Beam Penetration 6 MeV 9 MeV 12 MeV 4 cm Field Sizes and Energies for IOERT Colorectal Tumor Site Median/Typical Field Sizes 7.5 cm (5-6 cm on pelvic sidewall) Median/Typical Energy 6-9 MeV (up to12 MeV on pelvic sidewall) Sarcomas 9 cm (5-20 cm) 9 MeV (6-12 MeV) Pancreas 6-10 cm 6-12 MeV Head and Neck 5 cm (3-10 cm) 6 MeV (6-9 MeV) Gyn 10 cm (smaller on pelvic sidewall) Breast 4-8 cm 6-12 MeV Lung 7-9 cm 6-12 MeV 12 MeV (9-12 MeV) Mobile IOERT Solution Complete Treatment System No room shielding Mobile--use in multiple operating rooms 6 MeV - 12 MeV 3 10 cm Field Size 10 Gy/min dose rate
IORT using a Mobetron Mobetron Control Panel Power supply The Mobetron is a relatively lightweight mobile self-shielded linear accelerator Provides 4,6,9,& 12 MeV electrons with applicators from 3-10 cm (3-6 cm beveled) Unit is 1/6 the weight of a conventional accelerator allowing it to be moved from room to room or even between hospitals Minimal X-ray contamination eliminates the need for shielding of the O.R. suite Mobetron specs Gantry rotates +/- 45deg Head tilt +30-10deg Vertical range: 30cm Transport mod(head rotates 90deg horizontal) Treatment mod Beam stopper Range of motion Mobetron- Self shielded, mobile Linac Minimal radiation leakage Narrow electron energy spectrum No bending magnet ( major source of radiation leakage) Operates only in electron mode and hence low beam currents Minimal neutron background Has a compact 8inch thick lead beam stopper to reduce the inline X-ray contaminants produced by the scatter foil, ion chamber and collimator. Radiation survey: performed around at various locations around the Mobetron
Mobetron- Self shielded, mobile Linac Mobetron- Components At a distance of 3m (10ft) from the isocenter exposure should be 0.5 to 1mrem per procedure of 2min duration. Workload needs to be adjusted based on the exposure measurement. Treatment Module Treatment console Mobetron-Components Mobetron - Components Applicators Circular cone 3cm to 10cm diameter, in 0.5cm increments Circular Cones with 4 different angles-flat,15deg,30deg,45degs Cones are cylindrical shaped and collimate the beam directly onto to the surface of the irradiated volume. Rectangular applicators- tx for retroperitoneal or extremity sarcomas Soft docking QA fixture with Mirror Soft Docking Display Daily QA tool with applicator mount
Mobetron Accessories 1 2 3 4 5 6 1) Bookwalter Clamp 2) Sterile Cap for Gantry 3) Mirror Ring 4) IORT Applicators 5) Lead Shields 6) Lucite Bolus Mobetron in Operating Room
Patient Positioning GOAL: position patient so that tumor is in range of Mobetron beam Challenges: Mobetron footprint and range of motion Tumor location is different every time Patient Positioning Add extensions to table Position patient toward foot Slide table toward foot Reverse pedestal
Patient Positioning Pre-operative Dry Run Variables Patient size (height, weight) Tumor location Options Pedestal regular/reversed Use of table extensions Mobetron approach from side/feet Warning: table is at risk for tipping when weight is positioned far from pedestal Pre-operative Dry Run
Setting the Applicator Setting the Applicator Clamping the Applicator
Bookwalter Clamp and Mirror The mirror ring attaches to the applicator and modified Bookwalter clamp with a simple ball and socket joint Bookwalter Clamp and Mirror The mirror ring attaches to the applicator and modified Bookwalter clamp with a simple ball and socket joint The soft-docking system used by the Mobetron (a) The electron applicator, in contact with the tumor bed, is rigidly clamped to the surgical bed using a modified Bookwalter clamp. (b) The gantry being moved for soft docking to the applicator. Docking/Alignment Alignment: Position collimator vertically Bring bed to the Mobetron Gross adjustments using bed control (tilt, slide, height) Fine adjustments are done by radiation team BEWARE of collisions Patient could be injured Mirrored plate ($$$) could be damaged
Mobetron: Safety All evacuate room during treatment No additional room shielding is needed Hallway = safe zone Radiation emitted ONLY during therapy Effectiveness of Self-Shielding Average Exposure to OR Personnel during a Mobetron Treatment is 1/10 the exposure they receive on a transpacific airline flight as a passenger. A flight from San Francisco to China and back, will expose more than 40 Sv to a passenger during this trip (equivalent to the exposure of about 30 Mobetron treatments). Remote Monitoring (2-3 minutes) Screen will display 3 fields: Vital signs (Phillips screen) Vent data (from anesth. machine) Video directed at pt s head/airway Typical exposure dose from Mobetron treatment is < 1.2 Sv, or about half the normal daily background exposure rate in Portland. 75 IntraOp Medical Corporation
Remote Monitoring (2-3 minutes) During Beam On with the Mobetron Anesthesia is monitored by TV (or directly) Treatment takes ~ 2 minutes Staff exposure typically < 2.5 Sv per procedure During treatment the patient is monitored by anesthesia using a portable video camera and by direct observation through the O.R. windows 78
Acknowledgements Ackowledgements Surgical Oncology: Kevin Billingsley Dan Herzig Kim Lu Brett Sheppard V. Liana Tsikitis Koen DeGeest Melissa Moffitt Radiation Medicine: Charles Thomas Susha Pillai Dorothy Hargrove Rick Crilly Anesthesiology/PeriopMed: Ryan Anderson Grace Choi, RN Ryan Anderson, MD, PhD Nursing: Haley Sands, Grace Choi Technical Services: Bart Onoday