The impact of laterality on the incidence and prognosis of epithelial ovarian cancer.

ABSTRACT

INTRODUCTION: Epithelial ovarian cancer (EOC) is the most prevalent type of ovarian cancer, yet the impact of ovarian laterality has received limited attention. MATERIALS AND METHODS: We conducted a comprehensive investigation into the impact of laterality (left-right and bilateral-unilateral) on EOC incidence and prognosis, focusing on distinct subtypes. Binomial tests and Pearson's χ2 tests were employed to compare occurrence rates among laterality groups. Cox regression analyses were used to create a proportional hazards model for tumor prognosis. Nomograms were developed and validated, including internal validation via bootstrapping. RESULTS: Our study encompassed 20,790 EOC patients, revealing disparities in incidence and prognosis between unilateral and bilateral cases. Unilateral tumor development was notably predominant in clear cell, endometrioid, brenner, and mucinous subtypes, while bilateral involvement was more frequent in serous ovarian cancer. Laterality differences, reflecting disparities between the left and right sides, were chiefly evident in the incidence rates across various stages and in the prognosis of specific subtypes. Notably, mucinous ovarian cancer exhibited significantly better prognosis on the right side compared to the left (right tumors HR = 0.745, p = 0.015, CI 0.587-0.945). CONCLUSION: These findings emphasize the importance of considering ovarian laterality -both left-right and bilateral-unilateral aspects -as a critical factor influencing EOC incidence and prognosis, necessitating attention in clinical practice.