Proceedings of the 49th Annual ASTRO Meeting S749

2974 Risk of Late Toxicity After Radiotherapy in Patients With Connective Tissue Disorders: Association With

Connective Tissue Disorder Severity

D. G. Gold, R. C. Miller, M. E. Pinn, I. A. Petersen, T. G. Osborn, P. D. Brown

Mayo Clinic, Rochester, MN

Purpose/Objective(s): There is no way to reliably identify which patients with connective tissue disorders (CTDs) are at greatestrisk of radiotherapy-related complications. Building on our prior experience, we have postulated that CTD severity, as measured bythe number of organ systems involved, may be predictive of chronic radiation toxicity risk.

Materials/Methods: Medical records of 43 patients with CTDs (20 patients with scleroderma and 23 patients with systemic lupuserythematosus) who received radiotherapy at Mayo Clinic were reviewed. Risk of radiotherapy-related late toxicity was analyzedfor patients as a function of CTD severity. The division of patients into high- and low-severity CTD groups was made at the 50th

percentile of the number of organ systems involved with the CTD (low-severity CTD included patients with 2 to 3 organ systemsinvolved for scleroderma and 2 to 4 organ systems for lupus; high-severity CTD included patients with 4 to 5 organ systemsinvolved for scleroderma and 5 to 6 organ systems involved for lupus).

Results: All 20 scleroderma patients, and 17 of 23 lupus patients, were evaluable for long-term complications. For patientswith low-severity CTD, the 5- and 10-year chronic toxicity rates of any grade were 41% (95% CI, 19%–67%) and 52% (95%CI, 26%–88%), respectively. For patients with high-severity CTD, 5- and 10-year chronic toxicity rates of any grade were 79%(95% CI, 52%–93%) and 79% (95% CI, 52%–93%), respectively. Univariate analysis revealed a significant difference in therisk of late toxicity of any grade for patients with high-severity CTD when compared to patients with low-severity CTD (Figure;p = 0.006). No significant difference between the two groups could be demonstrated when analyzing risk of grade 3 or higher latetoxicity (p = 0.56), possibly because relatively few patients experienced grade $3 late toxicity events (3 patients among the 20 withscleroderma, 4 patients among the 17 with lupus).

Conclusions: This study suggests that the severity of the CTD, as estimated by the number of organ systems involved, is onepiece of information the clinician may use in evaluating the risk of radiotherapy-related late toxicity in patients with sclerodermaor lupus.

Author Disclosure: D.G. Gold, None; R.C. Miller, None; M.E. Pinn, None; I.A. Petersen, None; T.G. Osborn, None; P.D. Brown,None.

2975 Outcome Following Limb Salvage Surgery and External Beam Radiotherapy for High Grade Soft Tissue

Sarcomas of the Groin and Axilla

R. P. Phimolsarnti1, A. M. Griffin1, P. C. Ferguson1, C. N. Catton2, P. W. Chung2, R. S. Bell3, J. S. Wunder1, B. O’Sullivan2

1Mount Sinai Hospital, Toronto, ON, Canada, 2Princess Margaret Hospital, University Health Network, Toronto, ON, Canada,3University Health Network, Toronto, ON, Canada

Purpose/Objective(s): High grade soft tissue sarcomas (STS) located more proximally in the limb (axilla, groin) have poorer localcontrol following combined treatment with surgery and brachytherapy (Alektiar, Ann Surg Oncol, 2002). Our goal was to reviewour experience with treating high grade STS in these locations with limb-sparing surgery and external beam radiotherapy (EBRT).

Materials/Methods: From 1989–2004, patients with primary, high grade (grade 2 or 3) extremity STS treated with limb-sal-vage surgery and pre- or postoperative EBRT were identified from our prospectively collected database. Patients who presentedwith metastatic disease, had received prior radiotherapy or were treated with adjuvant chemotherapy were excluded. Of the 560patients who met the inclusion criteria, 418 had lower extremity (28 groin) and 142 upper extremity (16 axilla and 38 shoulder)lesions.

Results: Preoperative EBRT was employed in 294 patients, preop plus a postoperative boost in 48 and postop EBRT in 218. Prior‘unplanned excision’ occurred in 210 patients and surgical margins were microscopically positive in 99 patients and grossly pos-itive in 7. At a median follow-up of 52 months, the 5-year local recurrence (LR)-free survival, metastasis-free survival and overallsurvival for the entire group was 90.9%, 64.4% and 76.9%, respectively. There was no difference in local control between a groin oraxillary tumor location and a more distal extremity lesion (5 year LR-free survival of 90.6% and 91.0%, respectively). In Cox mul-tivariate analysis, with margin status, depth, prior ‘unplanned excision’ and anatomic site in the model, a positive surgical marginwas the only statistically significant factor. The 5-year LR-free survival was 93.8% for those cases with negative margins, com-pared to 78.2% for those with positive margins (p \ 0.00001).