985PThe effects of primary testicular tumour localization on prognosis in patients with nonseminomatous testis cancer

Abstract Background 5-year survival with platinum-based combination chemotherapies in testicular cancer is 95%. Existing prognostic scoring scales may be insufficient to predict which patient will benefit from treatment. Additional prognostic factors should be determined. Unlike left testicular vein, right testicular vein drains to vena cava. Therefore, the systemic spread of the testicular cancers of each side considered to be different due to the difference of vascular structures of the right and left testis. In this study, we aimed to investigate the effects of tumor localization on survival in patients with nonseminomatous testicular cancer. Methods We enrolled 321 non-seminomatous testicular cancer patients who followed up at Gulhane Research and Training Hospital in between January 1981, and December 2015. We retrospectively obtained data of demographic features, histopathological results, information of surgical operations and chemo-radiotherapy protocols, history of autologous stem cell transplantation from patients’ files. Results We enrolled 321 non-seminomatous testicular carcinoma patients and summarized demographic information and treatment methods in the table. Median age was 34 (18-77) years. The primary tumor was in left testis in 152 (47.2%) patients and in right testis in 170 (52.8%) patients. The most common histopathological diagnosis was mixed non-seminomatous germ cell tumor (39.4%). One hundred forty-six (44.3%) cases were metastatic at the time of diagnosis. Median follow-up period was 88.3 months (1-386). Median 10-year survival rate was 74.1%, and the 20-year survival rate was 70.7%. We examined the effect of primary tumor localization and found that primary tumor localization was significantly different regarding survival between left and right testis (337.6 months vs. NR, p = 0.001). In patients with a right testicular tumor the recurrence rate was significantly higher (84.7% vs. 68.2%; p = 0.002). Conclusions The localization of primary testicular tumor (left or right) was statistically significant regarding survival. The effect of tumor localization on survival was independent of the presence of metastasis at the time of diagnosis, histopathological type, site of metastasis, and disease stage. Legal entity responsible for the study Gulhane Education and Research Hospital. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.