AMORE (Ablative surgery, MOulage technique brachytherapy and REconstruction) for childhood head and neck rhabdomyosarcoma Buwalda, J.

Transcription

1 UvA-DARE (Digital Academic Repository) AMORE (Ablative surgery, MOulage technique brachytherapy and REconstruction) for childhood head and neck rhabdomyosarcoma Buwalda, J. Link to publication Citation for published version (APA): Buwalda, J. (2004). AMORE (Ablative surgery, MOulage technique brachytherapy and REconstruction) for childhood head and neck rhabdomyosarcoma General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. UvA-DARE is a service provided by the library of the University of Amsterdam ( Download date: 18 Aug 2018

2 Methods of the AMORE protocol Part of this chapter has been published in: M.J.I. Braam, J. Buwalda, S.D. Strackee, L.E.C.M. Blank, P.A. Voute, P.F. Schouwenburg, K.E. Bos (2000) Reconstructive surgery as part of the AMORE protocol in the treatment of head and neck soft-tissue sarcoma Eur J Plast Surg 2000;23:

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4 Methods of the AMORE protocol 2. Methods of the AMORE protocol The AMORE protocol requires a multidisciplinary team effort. The following disciplines are represented in the 'AMORE team' of the Academic Medical Center: (1) pediatric oncology, (2) otolaryngology and head and neck surgery, (3) radiotherapy, (4) plastic and reconstructive surgery and (5) radiology. In this chapter, planning of the procedure and technical details of the three different 'AMORE components' are described. 2.1 Planning of the AMORE protocol Primary local treatment Each newly diagnosed patient with HNRMS is discussed in a plenary multidisciplinary meeting, as there is a consistent policy to evaluate AMORE as local treatment in initially irresectable nonorbital HNRMS. The feasibility of AMORE is discussed at initial diagnosis and at routine evaluation after chemotherapy. Feasibility and timing of the procedure are determined by surgical criteria and, in case of macroscopically irresectable lesions, the response to multidrug chemotherapy (see paragraph ). When the procedure is deemed feasible, AMORE is scheduled, i.e. two consecutive surgical sessions (Amore I and II) and brachytherapy planning are arranged (tig.1). If necessary, the chemotherapeutic regimen is adapted to avoid surgery in aplasia. 'Non-feasible' patients are planned to receive external beam radiation therapy. Day MO Amore 1 tumor surgery/ mould implant recovery dose plannning start radiation stop radiation RE Amore II mould removal/ surgical reconstruction Figure 1. Time schedule of the AMORE protocol. A, ablative surgery; MO, moulage technique brachytherapy; RE, surgical reconstruction; AMORE I and II, first and second surgical session under general anesthesia. Salvage treatment Patients with residual disease after full treatment (chemotherapy and EBRT) or patients experiencing local recurrent disease, are also eligible for AMORE treatment. The same surgical feasibility criteria apply to these patients (see paragraph ). AMORE is scheduled after completing first-line treatment in patients with residual disease, and after second-line chemotherapy in recurrent cases. 65

5 Chapter 2 The AMORE procedure consists of three integrated parts (surgery, brachytherapy and reconstruction) and is scheduled in 8 days (fig.1). These three parts, although integrated, are outlined separately below. 2.2 The three different parts of the AMORE protocol Surgery Objectives Surgery as the first part of the AMORE protocol aims for a complete macroscopical removal of the residual (post-chemotherapy) tumor mass as defined by pre-operative CT/MR imaging. Preferably, this is acomplished by tumor resection without intralesional surgery. Hereby, the achievement of clear margins around the circumference of the tumor is not a goal per se. When resection around the lesion cannot be accomplished due to limited exposure of the tumor area, a complete piecemeal debulking is performed, guided by palpation of the landmarks and by using the previously defined borders on CT and or MRI studies. However, no macroscopical residual disease is to be left behind. In general, surgery is carried out as conservative as possible, in order to preserve uninvolved functionally important structures (e.g. cranial nerves, vessels, bone and dentition) and cosmesis, which is especially important in this young patient group. Bone resection is only performed in cases that display destruction of cortical bone and is withheld in patients with bone erosion at initial diagnosis only. Resection may be extended for an adequate exposure of the tumor area and to facilitate introduction of the brachytherapy-mould or the tissue used for reconstruction, for example by including an elective parotidectomy or (supraomohyoidal) neck dissection. After surgery, the wound bed possibly contains microscopic residual disease and the defect is suitablefor post-operative brachytherapy. Peroperative findings regarding the anatomy of the target area and vital structures are discussed with the brachytherapist in the operating room Surgical exclusion criteria The feasibility of complete macroscopical resection is based on clinical examination and preoperative imaging studies, which take place at diagnosis and as routine evaluation of the response to initial multidrug chemotherapy after 3 and 6 courses. Intracranial extension or invasion of the nasopharynx of the residual tumor mass preclude a macroscopically complete resection. Consequently, patients with these features are not eligible for the AMORE procedure. However, if AMORE surgery is deemed to be not feasible at routine evaluation, but the patient displays a continuing response to multi-agent chemotherapy, surgery is reconsidered during the course of treatment. 64

6 Methods of the AMORE protocol Surgical techniques and approaches to the tumor area The surgical approaches applied are in line with established techniques of head and neck oncologic surgery. However, due to the laxity of capsules and tendons and suppleness of all tissues encountered in children (as opposed to adult patients), in combination with the limited dimensions, a substantial gain in exposition may be achieved, which can decrease the need for extensive resection in order to reach the tumor area. For example, the infratemporal fossa or parapharygeal space can frequently be reached by subluxation of the mandible instead of a (partial) mandibulectomy. Selection of the surgical approach is depending on the site and size of the tumor (Table 1). Access to deeply seated parameningeal tumors, such as those in (1) the parapharyngeal space, (2) infratemporal and (3) pterygopalatine fossa, can be gained through (1) a submandibular approach (fig. 2) (2) parotidectomy and subsequent subluxation of the mandible or partial mandibulectomy (fig. 3) or (for small tumors) (3) a transantral approach via a sublabial antrostomy (fig. 4). Table 1. Surgical approach in AMORE according to tumor site Parameningeal Tumor site parapharyngeal space/ infratemporal fossa/ pterygopalatine fossa nasal cavity/ paranasal sinuses middle ear/ mastoid Surgical approach submandibular (chin-mastoid incision)*/ parotidectomy (Blair's incision)/transantral (sublabial incision) sublabial antrostomy/ 'Denker' operation lateral rhinotomy/ 'Moure' operation external ethmoidectomy/ midfacial degloving mastoidectomy (retro-auricular incision) Non-parameningcal Tumor site parotid region hard palate oropharynx neck Surgical approach superficial/ total conservative parotidectomy* hcmimaxillectomy submandibular ('pull through')* commando (median labiomandibulotomy) ± continuity resection* supraomohyoidal neck dissection ± skin excision radical or functional neck dissection ± skin excision *often, this approach is combined with a supraomohyoidal neck dissection Brachytherapy After macroscopic resection of the tumor, the wound bed, containing possible microscopic residual disease, is treated with brachytherapy. The aim is to deliver an adequate radiation dose in a short time span to a limited volume of tissue surrounding the wound bed. For this purpose, moulds are constructed for each individual patient to fit and to be placed into the 65

7 Chapter 2 Figure 2. Submandibular approach for a RMS of the right parapharyngeal space. After posterior retraction of the sternocleidomastoid muscle and elevation of the skin/plastysma flap, the posterior belly of the digastric muscle, nn. X, XI, XII and internal jugulary vein can be identified. By pulling the mandible anteriorly, the tumor (arrow) in the parapharyngeal space can be reached medial to the digastric muscle and the great vessels. surgical defect during the same session (Amore I). The moulds, produced of 5 mm thick layers of thermoplastic rubber (Gutta Percha) that are cut in a desired shape, are constituted of different parts, depending on the size and shape of the wound bed (fig. 5). Flexible catheters are positioned in between the Gutta Percha layers (fig. 6). To achieve a sufficient dose at the top of the mould (prevention of a decline in the isodose curves at the end of the wires) the catheters are either bent together towards the lop or placed to protrude from the mould (fig. 6). The number of catheters per part can vary from 1 to 5. The distance between the catheters is usually 5-7 mm. The catheters are numbered and the length (from entry into the mould to distal end) is measured. Surgical clips are placed at the lower edge of the mould and serve as a radiological landmark. If the mould is in close contact with vital tissues, i.e. skin, cranial nerves or major vessels, a layer of Tabotamp is added to achieve displacement, thereby reducing the radiation dose to these tissues, and to provide physical protection. Finally, the wound is closed over the mould and the catheters are left to protrude through the closed incision (fig. 7). Treatment planning is performed two days after surgery (fig. 1). Dummy sources with,m identifiable configuration are inserted into the catheters. The clinical target volume (CTV) is defined as being a 5 mm envelop of tissue starting from the surface of the mould, i.e. 10 mm from the individual sources. A CT scan is made to verify the position of the mould in relation to the CTV and the dose-limiting critical structures. Reconstruction of the implant, based on orthogonal simulation films (fig. 8A-B), and subsequent dose calculations are performed using the Plato brachytherapy treatment planning system (Nucletron-Oldelft, Veenendaal, The 66

8 Methods of the AMORE protocol Figure 5. Moulds 'in situ'. The composition of the several parts exactly fits the surgical defect, ensuring an adequate dose distribution to the target area. Figure 3. Parotidectomy-approach to a RMS in the right infratemporal fossa. In this patient a total conservative parotidectomy and partial mandibulectomy (because of destruction of cortical bone) have been performed. The two major branches of the facial nerve have been identified and the parotid gland is pulled anteriorly to reach the infratemporal fossa. Figure 6. The separate parts which together constitute the mould. Hollow flexible polyethilene cathethers are 'sandwiched' between two layers of Gutta Percha. The catheters are either bent together towards the top of the mould or protrude from the mould to ensure an adequate dose (arrows). Figure 4. Trans-antral approach for a RMS in the right pterygopalatine fossa. The mucosa and periostium are incised in the buccogingival fold and access is gained to the antrum of the maxillary sinus (above the level of the permanent teeth). After removal of the posterior sinus wall, the pterygopalatine fossa is reached. Figure 7. Situation after closure of an extended parotidectomy incision. The catheters protrude from the wound and can be afterloaded with Iridium 192 wire sources. 67

9 Chapter 2 Figure 8A Figure 8B Orthogonal X-ray films after introduction of dummy sources with identifiable configuration. The coordinates of the separate sources are given into the computer program (Plato (IMPS)). Netherlands) (fig. 9A-B). The dose is delivered according to the reference dose rate curve encompassing the CTV (prescription dose rate). The prescribed dose to the CTV is between 40 and 50 Cy, individualized depending on peroperative findings regarding tumor bed and vital structures. The radionuclide used for brachytherapy is lridium-192 (Ir 192 ). Ir 192 is formed in a nuclear reactor when stable Ir 141 absorbs a neutron. It is a photon energy source emitting a broad spectrum of gamma rays with an average energy of 0.37 MeV. Ir 192 has a half-life of 74.2 days and a half value layer in lead of 2.5 mm (Table 2). In the majority of cases, linear Ir 1 ''- 0.3 mm, platinum clad wire sources (1.8mG/cm, Amersham Laboratories, Buckinghamshire, UK) are used, cut to the desired length and afterloaded either manually or remotely with a microselectron-ldr (Nucletron-Oldelft, Veenendaal, The Netherlands) (fig. 10). Continuous low-dose rate (LDR, Table 2. Summary of decay properties of Ir 1 ' 1 -' Decay modes B (0.67 MeV eff max) to excited states of,92 Pt (95.6%) electron capture to excited states of ' c ' 2 Os (4.4%) Energy of primary gamma rays-mev (number per decayl 0.206(.034), ), 0.308(.298), ), 0.468(.476), 0.485(.032), 0.589(.044), 0.604(.081), 0.612(.052) Average gamma ray energy: 0.37 MeV Average number of gamma rays per decay: 2.2 Additional photons: Pt and Os fluorescent X-rays (Most numerous: MeV (.046)) Half-life of ground state: 74.2 days Gamma constant: 4.62 R cm 2 mci ' hr' Air kerma rate constant 4.11 cgy cm 2 mci"' hr' 68

10 Methods of the AMORE protocol Figure 9A Figure 9B Computer-aided two-dimensional calculation of the distribution of the radiation dose. Isodose curves (in cgy/h) are drawn around the sources. i.e Gy/ h) brachytherapy is given, requiring treatment in 'isolation'. Therefore, the patient is transferred the radiotherapy ward, where special shielding is provided. Adequate analgetic medication is given, but sedative medication or general anesthesia are not needed. The treatment time is determined by dividing the prescribed dose by the prescription dose rate, but in general averages 4 days (range 3-6 days), without interruption. More recently, a pulsed dose rate (PDR) stepping source technique has been applied in 5 cases. In this technique, a source with a high concentration of lr 192 (1 Ci) at the tip progresses through the catheter in 5mm-steps by remote afterloading (microselectron-pdr, Nucletron-Oldelft, Figure 10. Patient (8 years of age) at the radiotherapy ward, connected to the microselectron-ldr for afterloading low dose rate brachytherapy. 69

11 Chapter 2 Figure 11 CT scan image at PDR brachytherapy treatment planning. The residual tumor mass in the parapharyngeal space has been removed and the Gutta Percha mould is in situ. The mould is loaded with dummies and dose distribution is calculated. Reference isodose lines (cgy/h) around the moulage are depicted in color: green line 80 cgy/h, outer yellow line 100 cgy/h, inner yellow line 125 cgy/h, light blue line 1 56 cgy/h, dark blue line 250 cgy/h. Veenendaal, The Netherlands). By variation of the dwell time after introduction of the sources, a more conformal dose distribution can be obtained. Planning is based on CT scans instead of orthogonal radiographs and dose distribution can be directly related to the CTV (fig. 11). When the PDR technique is used, shielding is not needed between the pulses, facilitating nursing and visiting Reconstructive surgery Objectives Surgical reconstruction of the wound bed is performed to (1) achieve primary wound healing, (2) avoid wound breakdown and fistulae, (3) protect and support vital structures, 4) provide uncompromized tissue into the irradiated wound bed, (5) prevent communications between the upper aerodigestive tract and the intracranial space, (6) obliterate dead spaces, and (7) restore function and contour Selection of flaps Local and regional transpositional flaps or free vascularized muscle flaps can be used for reconstruction of the wound bed. The choice of the flap depends on site and size of the defect, composition of the defect, length of the pedicle needed, condition of the recipient vessels and experience of the surgeon. Local flaps of the galea, temporalis and frontalis muscle may be used to reconstruct smaller defects or to cover bone surfaces (e.g. in paranasal sinus tumors). Larger defects require large 70

12 Methods of the AMORE protocol regional flaps (e.g. latissimus dorsi, pectoralis major and sternocleidomastoid) or free flaps. A disadvantage of bulky pedicled flaps (pectoralis major and latissimus dorsi) is that they are less adaptable and often result in contour deformities as a consequence of tunnelling of the pedicle. The sternocleidomastoid regional flap has a limited arc of rotation due to its segmental vascularization, but can be used for reconstruction of the parapharyngeal space. Latissimus dorsi and rectus abdominis free flaps are pliable and deliver an adequate bulk and are therefore suitable for reconstruction of three-dimensional complex defects (neck, parapharyngeal space, infratemporal fossa). Advantages of the rectus abdominis free flap are the large vascular pedicle and the tendineous intersections, facilitating fixation to the cranial base. The gracilis free flap delivers less bulk and has a short vascular pedicle. The free radial forearm (fasciocutaneous) flap is generally used only to reconstruct mucosal (intraoral) or cutaneous defects. When morbidity at the donor site is considered, visible soft-tissue defects can result from temporal is and sternocleidomastoid transpositional flaps. Seroma formation frequently occurs at the latissimus dorsi donor site. Conventional harvesting of the gracilis muscle results in a large scar. Disadvantages of the free radial forearm flap include a possible lesion of the superficial sensory branch of the radial nerve, adhesion of the flexor tendons to the skin graft and compromized vascular supply of the hand (which entirely depends on the ulnar artery), leading to easy fatigue Surgical technique Reconstructive surgery is scheduled 7 days after tumor surgery (AMORE I) and 1-2 days postirradiation in a second surgical session, AMORE II (fig. 1). The moulds are taken out, followed by debridement and rinsing of the wound bed. In our patient population the following flaps were used: latissimus dorsi (n=9), rectus abdominis (n=6), gracilis (n=3) and radial forearm (n=1) as free revascularized flaps, and sternocleidomastoid (n=5), latissimus dorsi (n=2), galea (n=1) and fascia temporalis (n=1) as transpositional flaps. The recipient vessels for the free flaps consisted of the external carotid artery and internal jugulary vein or one of their branches (end-to-end or end-to-side). On one occasion a loop of the vena saphena magna was used. A skin graft was used for intra-oral lining to prevent granulation. All patients received Rheomacrodex (Braun NPB Medical, Oss, The Netherlands) for 5 days post-operatively. Postoperative monitoring took place by direct inspection. 71

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