RESULTS:

1. Wide excision Wide excision + RT 1.0 1.0 1.0 < 50 years Wide excision 50-59 years 0.9 Mastectomy 0.9 0.9 Mastectomy 60-69 years 0.8 0.8 0.8 > 70 years Wide excision + RT 0.7 0.7 0.7 Mastectomy + RT 0.6 0.6 0.6 No. at risk Years 0 5 10 12 Mastectomy + RT 0.5 0.5 0.5 % Cause-Specific Survival • 382 220 106 86 • 207 119 47 34 • 68 42 35 • 115 49 13 9 < 50 years 50-59 years % Cause Specific Survival 0.4 0.4 60-69 years 0.4 No. at risk Years 0 5 10 12 No. at risk Years 0 5 10 12 % Cause-Specific Survival Wide excision 198 95 30 19 23 10 3 2 134 82 29 17 11 3 0 0 > 70 years Wide excision 64 26 7 6 6 2 2 1 154 78 27 16 28 11 2 2 p = 0.02 0.3 0.3 Wide excision + RT 0.3 Wide excision + RT Mastectomy Mastectomy p = 0.002 p < 0.0001 0.2 0.2 Mastectomy + RT 0.2 Mastectomy + RT 0.1 0.1 0.1 0.0 0.0 0.0 0 1 2 3 4 5 6 7 8 9 10 11 12 < 50 years 0 10 0 1 2 3 4 5 6 7 8 9 10 11 12 Years 60-69 years Years Years Malignant Phyllodes Tumor of the Female Breast: the Association of Primary Therapy with Cause-Specific Survival from the Surveillance, Epidemiology, and End Results (SEER) Program. O. Kenneth Macdonald, Christopher M. Lee, Jonathan D. Tward, Craig D. Chappel, David K. Gaffney 1Department of Radiation Oncology, Huntsman Cancer Hospital at the University of Utah, Salt Lake City, Utah RESULTS: Table 1 contains information on the patient, tumor and treatment characteristics in 821 women. With a median follow-up of 5.7 years, CSS was 91%, 89%, and 89%, at 5-, 10- and 15-years, respectively. A total of 157 deaths occurred, 72 were due to recurrent or progressive breast disease and 19 due to secondary, non-breast malignancies. Mastectomy was performed in 428 women (52%) and wide excision or lumpectomy in 393 (48%). Women undergoing mastectomy were significantly older (p = 0.004) and had higher T category disease (p <0.0001). Primary wide excision predicted for improved rates of CSS compared to mastectomy or any surgery with adjuvant RT (p <0.0001, Figure). On multivariate analysis, predictors for cause-specific mortality included older age (p = 0.01) and mastectomy or any surgery with adjuvant RT (p = 0.0001, Table 2). OBJECTIVE: Malignant phyllodes tumor is a rare and potentially aggressive subtype of fibro-epithelial neoplasm of the breast. Little information is available regarding the optimal surgical approach and rarer still are survival data following primary therapy. This analysis used a large population database to identify clinical and pathological factors that predict for cause-specific survival (CSS), evaluate the role of adjuvant radio-therapy relative to the survival end-point, and define a subgroup of women at greatest risk of cause-specific death for whom surgery alone may not be adequate initial therapy. Cause-specific survival adjusted for age Estimated cause-specific survival by tumor size, adjusted by treatment METHODS: Data were obtained from the Surveillance, Epidemiology, and End Results Program (SEER) for the years 1983-2002. Eight hundred twenty-one women who received resection for primary non-metastatic malignant phyllodes tumor of the breast were included. Analyses of patient, pathologic, and treatment characteristics were performed using univariate and multivariate Cox regression analyses for the CSS endpoint. CONCLUSIONS: As the largest reported population analysis to date, this study reveals that women undergoing wide excision have at the minimum similar cancer-specific mortality compared to women undergoing mastectomy for malignant phyllodes tumor of the breast. Breast conservation surgery should be considered on a case-by-case basis and should not be considered inferior therapy relating to the cause-specific survival endpoint. The role of adjuvant radiotherapy is uncertain and requires further investigation. Tumor < 5 cm Tumor > 5 cm ● Huntsman Cancer Institute University of Utah