Risk of Gynecologic Cancer as Second versus First Primary Cancer in Japan

This study aimed to determine whether the risk conferred by gynecologic cancer (GC) as second primary cancer (SPC) differs from that associated with GC as first primary cancer (FPC). We investigated the correlations between FPC/SPC and the characteristics and prognoses of 1,645 GC patients (701 with cervical cancer [CC], 641 with endometrial cancer [EM], and 303 with ovarian cancer [OV]). The χ2 test and the Kaplan–Meier method were used to determine whether FPC/SPC and the characteristics and prognoses of GC patients. Of the SPC patients, 26 (3.7%) had CC, 53 (8.3%) had EM, and 31 (10.2%) had OV. The most common previous cancer type in SPC of GC patients was breast cancer, which was observed in 13 patients (50.0%) with CC, 23 (43.4%) with EM, and 16 (51.6%) with OV. In all patients with CC, EM, and OV as SPC, the stage was significantly associated with recurrence. There were no significant differences in the morbidity or mortality of CC, EM, or OV patients between those with FPC and those with SPC. The risk of SPC development in GC patients varied, ranging from 3.5% (CC) to 10.3% (OV) of patients.