Mesenchymal molecular subtype is an independent predictor of severe postoperative complications after primary debulking surgery for advanced ovarian cancer.

OBJECTIVE: To evaluate the contribution of molecular subtype to 30-day postoperative complications and 90-day mortality after primary debulking surgery (PDS) in advanced stage high-grade serous ovarian cancer (HGSOC).

METHODS: Patients with stages III-IV HGSOC undergoing PDS from 1994 to 2011 with available molecular subtyping were included. Residual disease (RD) status was categorized as 0, 0.1-0.5, 0.6-1.0, or >1 cm. Surgical complexity scores were calculated as high, intermediate, or low as previously published. Postoperative complications were graded according to the modified Accordion classification 0-4 scale; severe was defined as grade ≥3. Molecular subtypes were derived from Agilent 4 × 44k tumor mRNA expression profiles and categorized as mesenchymal (MES) or non-mesenchymal (non-MES). Logistic regression modeling was used to assess associations.

RESULTS: Of 329 patients, 68.7% were stage IIIC, 80.5% had RD ≤1 cm, 28.0% had MES subtype, and 19.5% had a grade 3-4 complication; 90-day mortality was 5.8%. In univariate analysis, patients with MES subtype were more likely to have severe complications compared to non-MES (31.5 vs. 14.8%; OR 2.66, 95% CI 1.51-4.69; p < 0.001). MES subtype remained an independent predictor of complications (adjusted OR 2.14, 95% CI 1.17-3.92; p = 0.01) in a multivariable model which included ASA score, preoperative albumin, and surgical complexity. There was no statistical difference in 90-day mortality in patients with MES compared to non-MES subtype (7.6 vs. 5.1%; OR 1.54, 95% CI 0.59-4.05; p = 0.38).

CONCLUSIONS: MES subtype is an independent predictor of severe postoperative morbidity and adds to the potential use of pre-operative molecular testing in planning primary treatment of patients with advanced ovarian cancer.