The co-occurrence of breast cancer and soft tissue sarcoma in a single cohort series

Background: The incidence of breast cancer (BC) and soft tissue sarcoma (STS) in the Israeli general population is 97/10 ⁵ women and 1.5/10 ⁵ persons. It is expected that 1.5/10 ⁵ × 49/10 ⁵ of the women in the general population will have both BC and STS. Methods: A retrospective search of 1350 adult STS patient files that were recorded between 1995 and 2005. Results: One hundred thirty-four patients with STS had multiple primary malignancies. BC was observed in 27/64 patients (42%) before/after the STS: BC-first in 19/27, BC-later in 8/27. Of 19 with BC-first the STS was related to radiotherapy in 2, and to lymphedema in 1. Of 8 STS-first, only 1 got chemotherapy before BC. Median interval between first to second malignancies was 6.9 years for BC-first, and 3.8 for BC-later. The incidence of BC among all patients with STS-first followed by a second malignancy is 8/58 (14%), or 27/890 (3%) of all women STS-patients in the registry. The incidence of STS among the BC patients was low, and most of our cases were therapy unrelated. Median survival for BC-first was 305 months, versus 213 for STS-first. Conclusions: BC and STS may naturally occur in the same individual. The etiology for this phenomenon is unclear. Practically, BC screening in patients with STS is warranted.