Impact of adjuvant chemotherapy on the overall survival of patients with advanced stage low-grade serous ovarian carcinoma (130)

Abstract

<b>Objectives:</b> Low-grade serous ovarian carcinoma (LGSOC) is a rare, relatively chemo-resistant histologic subtype of ovarian carcinoma. The impact of adjuvant chemotherapy on the survival of patients with the advanced-stage disease is not well defined. We aimed to utilize a large hospital-based database and investigate the survival of patients who did and did not receive adjuvant chemotherapy. <b>Methods:</b> Patients diagnosed between 2010-2015 with FIGO stage II-IV low-grade serous ovarian carcinoma who underwent primary debulking surgery with known residual disease status and had at least one month of follow-up were identified. Adjuvant chemotherapy or hormonal treatment was defined as receipt of chemotherapy or hormonal treatment within six months from surgery. Clinical-pathologic and demographic characteristics were compared with the Chi-square test. Overall survival was evaluated following the generation of Kaplan-Meier curves and compared with the log-rank test. A Cox model was constructed to control for a priori selected confounders. <b>Results:</b> A total of 618 patients with stage II-IV LGSOC were identified; 501 (81.1%) patients received adjuvant chemotherapy while 117 (18.9%) patients did not. In the present cohort, hormonal therapy was rarely administered (<i>n</i>=22, 3.6%). There were no differences between the two treatment groups in terms of age, presence of comorbid conditions, type of treatment facility, and insurance status. In the present cohort, the rate of CGR was 67.8%; 66.1%, and 75.2% among patients who did and did not receive adjuvant chemotherapy (p=0.057). The rate of adjuvant chemotherapy use was 67.4% for patients with stage II disease compared to 83.2% and 86.5% for those with stage III and IV disease, respectively. The median follow-up duration of the present cohort was 47.97 months. There was no difference in OS between patients who did and did not receive adjuvant chemotherapy (p=0.78); 4-year OS were 77.5% and 76.1%, respectively. Following stratification by residual disease status, adjuvant chemotherapy was not associated with a survival benefit for patients who achieved CGR (p=0.60; 4-year OS rates 85.5% and 79.5%, respectively) or had the gross residual disease (p=0.85; 4-year OS rates 63.1% and 66.3%, respectively). After controlling for patient age, presence of medical comorbid conditions, disease stage, and residual disease status, administration of adjuvant chemotherapy was not associated with better overall survival (HR: 0.87, 95% CI: 0.55-1.38). On the contrary, the presence of gross residual disease (HR: 2.25, 95% CI: 1.58, 3.21) was associated with worse overall survival. <b>Conclusions:</b> Adjuvant chemotherapy may not be associated with an overall survival benefit for patients with advanced-stage LGSOC.