Secondary Bone Marrow Malignancies after Adjuvant Chemotherapy for Breast Cancer: A Report of 2 Cases and a Review of the Literature

Purpose Secondary malignancies are new cancers occurring in patients previously treated with radiation or chemotherapy for a primary tumor. Secondary cancers are not related to the primary tumor, and may develop months or years after cancer treatment: they are usually a result of the first cancer therapy. Chemotherapy and radiotherapy may increase the risk of second cancers, such as skin tumors (basal or squamous cell carcinoma) or acute leukemia. Methods A patient with B-lymphoma and a patient with multiple myeloma, previously treated for breast cancer, are presented. Results We report the cases of 2 patients treated with adjuvant therapy for breast cancer who developed secondary bone marrow malignancies 15 years after primary treatment. Conclusions By literature review, these 2 cases do not support the relationship between primary tumor treatment and secondary cancer, but strongly suggest the need for histologic samples when bone metastasis occurred after years from diagnosis of breast cancer. In this setting, the oncologist should take into account a secondary bone marrow tumor before starting treatment for breast cancer.