Adjuvant chemotherapy vs. observation in stage I clear cell ovarian carcinoma: a systematic review and meta-analysis

The role of adjuvant chemotherapy in surgically staged stage I clear cell ovarian cancer (OCCC) is unclear. Here, we performed a systematic review and meta-analysis in order to evaluate the role of chemotherapy vs. observation in stage I OCCC. This systematic review was registered in the International Prospective Register of Systematic Reviews (PROSPERO; ID: #129628). A protocol was defined prior to the search include the population criteria, description of interventions, comparisons, and the outcomes of interest, according to the PRIMA guidelines. Overall, the study population included 5073 women. Stage I OCCC experienced a 5-year disease-free survival and a 5-year overall survival of 83.7% and 86.9%, respectively. Pooled data suggested that in the overall population adjuvant chemotherapy did not impact on 5-year disease free survival (test for overall effect, Z = 0.18; p = 0.86) and 5-year overall survival (test for overall effect, Z = 0.62; p = 0.53). Focusing on 2264 stage IC OCCC we observed that adjuvant correlated with an improvement in overall survival (OR: 0.70 (95%CI: 0.52 to 0.93); Z = 2.44; p = 0.01). In conclusion our study underlines that adjuvant chemotherapy could be reserved for patients with stage IC OCCC; while in stage IA and IB it could be safely omitted. Owing to the inherent biases of the studies included in the meta-analysis further prospective evidences are needed.