NONBREAST SECOND MALIGNANCIES AFTER TREATMENT OF PRIMARY BREAST CANCER

Purpose: To determine the incidence and risk factors for nonbreast second malignancies (NBSMs) in women after treatment for primary breast cancer. Methods and Materials: Between January 1985 and December 1995, a total of 1,084 breast cancer patients were analyzed. for NBSMs. Detailed analysis was carried out for age, family history, disease stage, radiation therapy, chemotherapy, hormone therapy, other clinical/pathologic characteristics, and site of NBSMs. The Cox proportional hazard regression model was used to estimate the relative risk of NBSMs. Results: Median follow-up was 12 years. In total, 33 cases of NBSMs were noted in 29 patients. The overall incidence of NBSM was 3%, and the median time for NBSMs was 7 years. The most common NBSMs were gynecologic (22 patients), gastrointestinal (4 patients), head and neck (3 patients), hematologic (2 patients), lung (1 patient), and thyroid 0 patient). The NBSMs rate at 12 years was 2.4% for both mastectomy and radiation therapy groups. In the subset of patients less than 45 years of age at the time of treatment, the NBSMs rate was 0.7% as compared with 4.6% in patients more than 45 years of age (p = 0.001). Statistically significant higher incidences of endometrial and ovarian cancer were seen in patients with hormonal therapy (5.2%) as compared with patients without hormonal therapy (1.8%,p = 0.002). Women with a family history of breast cancer had a higher incidence (6%) of endometrial and ovarian malignancy compared with women without such a history (2.1%,p = 0.003). Chemotherapy did not affect the risk of second malignancy. Conclusion: The most common NBSMs in this study were gynecologic. Family history of breast cancer was a high risk factor for NBSMs. No risk of NBSMs with radiotherapy was observed. (C) 2009 Elsevier Inc.