The Canadian Radiosurgical Society Meeting - Abstracts

Banff, Alberta March 4-5, 2005 Can. J. Neurol. Sci. 2005; 32:378-389 Over two beautiful sunny days in Banff, framed by the majestic Rocky Mountains, the Canadian stereotactic radiosurgical community met for the first time. All radiosurgery programs from across Canada participated and over 50 registrants, from all specialties, were represented including neurosurgery, radiation oncology, medical physics, and radiation technology. The objectives of the meeting were to (i) determine if there was sufficient interest in forming a radiosurgical society, (ii) discuss present indications, protocols, and challenges in the field, and (iii) plan multi-centre collaborative trials of stereotactic radiosurgery in Canada. The meeting was a resounding success with all three objectives achieved. Thanks to sponsorship from four of the six major manufacturers of stereotactic radiosurgery equipment, the conference organizers were able to invite three distinguished keynote speakers. Dr. Michael Schwartz, a neurosurgical pioneer of radiosurgery from Toronto, started off the program by presenting the history of stereotactic radiosurgery in Canada from the first modified linear acceleratorbased program at McGill in 1985, through to the TorontoSunnybrook, Ottawa, Vancouver, Toronto-PMH, Calgary, and Halifax programs, followed most recently by the Gamma KnifeTM units in Winnipeg, Sherbrooke and, imminently, the Toronto Western Hospital. Dr. David Larson, a radiation oncologist from the University of California San Francisco, gave an excellent presentation on the controversies that exist in the field and dissected the dogma to reveal that there is much we do not know and can be learned with the appropriate clinical trials. Dr. Samuel Ryu, a radiation oncologist from Henry Ford Hospital in Detroit, Michigan, discussed his cutting-edge work on stereotactic radiosurgery for spinal disorders, including both metastatic and benign disease. The impressive results of his phase II dose escalation trial for spinal radiosurgery portend an exciting future for the field. All three keynote speakers gave outstanding talks and each was awarded a white cowboy hat, Calgary’s symbol of hospitality and respect. Thirty-three abstracts were presented and are included in these proceedings. The themes were diverse and the presentations were made by radiation oncologists, neurosurgeons, physicists, and radiation technologists. Not only was there much discussion after each talk, but a final round-table session at the conclusion of the meeting lasted 90 minutes (despite the attraction of great skiing). A major objective, and success, of the meeting was the interest in forming the Canadian Radiosurgery Society (CaRS) that, at least in the near future, will focus on neurologic disease. A formal societal structure was not finalized. However, a multidisciplinary committee comprised of Drs. Michael Schwartz (Toronto), Michael McKenzie (Vancouver) and James Robar (Halifax) was struck to organize next year’s meeting in the Toronto area. The principle of having the organizing committee always include a medical physicist, radiation oncologist, and neurosurgeon was agreed upon, so as to reflect the multidisciplinary nature and practice of this group. Key goals of CaRS were identified: to educate physicians, to establish guidelines for referral, and to facilitate Canada-wide multicentre studies. The meeting saw the beginnings of just such a collaboration, with Drs. Brian Toyota from Vancouver and Cynthia Ménard from Toronto-PMH presenting results of their own surveys of stereotactic radiosurgery across Canada from both the neurosurgical and radiation oncology perspectives. Perhaps contrary to the situation south of the border, Canada is well positioned to organize national radiosurgical clinical trials and collaborative outcome analyses. Several conditions were identified that could benefit from standardized treatment and multi-centre outcome data collection. Dr. Ian Parney (Calgary) will spearhead an initiative on brain metastases and the role of stereotactic radiosurgery vs. surgical resection. Drs. Ian Fleetwood (Halifax) and John Wong (Calgary) will focus on vascular malformations, especially inoperable cavernous malformations and those large arteriovenous malformations not amenable to “traditional” radiosurgical techniques. Dr. Elizabeth Yan (Calgary) will tackle pituitary and parasellar benign tumors, and Dr. Brian Toyota, acoustic neuromas. Dr. Normand Laperriere (Toronto) will focus on meningioma treatment, and Dr. Michael West (Winnipeg) will spearhead the functional stereotactic radiosurgery theme. Drs. Brenda Clark (Vancouver) and Chris Newcomb (Calgary) will address the medical physics components of these studies, such as dose specification, quality assurance, and treatment verification. Both radiation technologists and nurses will collaborate to develop and share patient educational materials about radiosurgery. Despite 20 years of radiosurgery in Canada, only recently has a critical mass of programs formed and matured. Whereas previous regional rivalries and debates about technology threatened to distract those involved in radiosurgery from the real goal of patient care, we have now finally come together with an ambitious plan for crosscountry collaboration. As Dr. Larson concluded, "Everyone was enthusiastic, polite, interested, engaged, and democratic. The meeting was a great success." It took a long time coming, but we’re off to a terrific start. Zelma Kiss, John Wong 2816 LE JOURNAL CANADIEN DES SCIENCES NEUROLOGIQUES Volume 32, No. 3 – August 2005 379 1. BC Cancer Agency Stereotactic Program: Our role in the team Christine Alexander RT, Lorraine Geddes RT BC Cancer Agency, Vancouver, BC B.C Cancer Agency has been involved in treating patients with stereotactic radiotherapy and radiosurgery at its Vancouver centre since 1997. During this time we have implemented and refined our treatment process and techniques. A multidisciplinary approach is adopted throughout the entire treatment process and we will primarily focus on the role of the radiation therapists. The information presented will describe the patients’ experience from their initial consultation (New Patient visit) through post treatment care and follow up. The patient group served by each treatment modality will be identified and the differences in the steps involved in the treatment planning processes with respect to the impact to the patient will be outlined. The treatment day from the perspective of the patient and the individual members of the multidisciplinary team will be shared. The educational and support resources available to the patient have evolved along with the program. The need to optimise patients’ and their family’s awareness of these services will be discussed. 2. Radiotherapy for the Management of unresectable/ recurrent benign and malignant Meningiomas Al-Ghamdi, S., Malone, S., Szanto J., Victor, G. University of Ottawa, Ottawa, Ontario Purpose/Objective: We analyzed the tumour control and toxicity obtained with radiotherapy in the treatment of meningiomas. Material and Methods: All patients with intra-cranial meningioma treated at ORCC with radiotherapy (XRT) between 1987-2003 were included. Treatment was as follows: Conventional (C) external beam radiotherapy (EBRT) 38 patients (29 with surgery), 50-75 Gy (mean: 58 Gy), 1987-2003; 3D conformal EBRT 22 patients (11 with surgery), 50-60 Gy, 1995-2003; fractionated stereotactic radiotherapy (SRT) 16 patients, 50-50.4 Gy, 19972001. MRI CT image fusion was used in patients treated with 3DCRT or SRT. SRT was performed using a relocatable frame and bite block. Planning target volume included a margin of 2-5 mm around gross tumour volume for benign and 10-20 mm for malignant tumours. SRT was planned using the X-Knife treatment planning system. Results: At the time of radiotherapy, 31 (41%) had benign and 19 (25%) had malignant tumours, 22 (29%) had unknown differentiation level (12 had previously documented benign pathology). Number of prior surgeries was: none (46%), 1 (68 %), 2 (22%), > 2 surgery (10%). Seventy percent of tumours were in the skull base. Mean XRT dose was 53-54 Gy for benign or unknown and 60 Gy for malignant tumors. Amongst those receiving combination therapy, surgery was performed prior to radiotherapy. Fifty-six percent of malignant tumours were completely resected. 2/5 year progression free survival was 93%/88% for all patients (97%/89% for benign or unknown differentiation and 86%/86% for malignant tumours). Toxicity potentially related to radiotherapy in patients treated with CEBRT/3DCRT was (#pts/#pts): overall (13/3), stroke (2/1), neurocognitive deficits (9/2), unstable gait (1/0), tinnitus (1/0). There was no recorded toxicity for SRT. Conclusion: Radiotherapy is effective management of unresectable or recurrent meningiomas of benign and malignant histology. With modern 3DCRT and SRT techniques the risk of serious morbidity is low. 3. Embolization prior to radiosurgery reduces the obliteration rate for AVMs. Yuri M. Andrade-Souza, Meera Ramani, Daryl Scora, May N. Tsao, Karel terBrugge, Michael L. Schwartz Division of Neurosurgery and Department of Radiation Oncology, Sunnybrook and Women’s College Health Sciences Centre; University of Toronto, Ontario, Canada. Objective: To analyze the impact of liquid embolization (enbucrilate) prior to radiosurgical treatment in the obliteration rate for brain AVMs. Method: Thirty-nine patients with embolization prior to radiosurgical treatment were matched according to marginal dose, volume and anatomical location with 39 other patients (control) selected randomly that did not have prior embolization. Results: The median follow-up was 42 months (range 27-118). The median age of the patients was 37 years (range 5-67, mean 35.9) and 51.3% were women and 48.7% were men. There was no difference in relation to volume (mean: 6.45cm3), marginal dose (mean: 17.3Gy) or AVM loca