Characteristics and outcomes of therapy-related second malignant neoplasms in our hospital

Abstract

BACKGROUND: Although therapy-related second malignant neoplasms (SMNs) have been elucidated, their course and prognoses remain unknown. METHODS: We retrospectively investigated 603 cases of children who were treated at our hospital between 1980 and 2010. RESULTS: Eighteen patients developed SMNs. The most common primary malignant neoplasm (PMN) was acute leukemia (n=11). SMNs were hematopoietic tumors (n=5), thyroid cancer (n=3), breast cancer (n=3), digestive cancer (n=3), bone and soft tissue tumors (n=2), renal cancer (n=1), and pleural tumor (n=1). The median time from diagnosis of PMNs to diagnosis of treatment-related hematopoietic tumor was 6.5 years (range, 3.25–15.3 years), and that to diagnosis of treatment-related solid tumor was 13.9 years (range, 4.3–26.6 years). SMNs were detected during routine medical examination (n=9), from subjective symptoms (n=8), and by autopsy (n=1). Four of the patients with treatment-related hematopoietic tumors received hematopoietic cell transplantation, and twelve of the patients with treatment-related solid tumors received standard treatment. Two patients died before a definitive diagnosis was made. Five patients died of causes, namely, treatment-related hematopoietic tumor (n=2), treatment-related solid tumor (n=2), and recurrence of the PMN (n=1). Despite early detection and standard treatment, one patient with breast cancer developed brain metastasis two years later. CONCLUSIONS: Although early detection is necessary to improve the prognoses of SMNs, it is not enough. Further elucidation of SMN etiology, development of new treatments for SMNs, and development of PMN treatments with reduced risk of SMNs are necessary.