Surgical extent and its association with major postoperative complications in advanced ovarian cancer: initial validation of the Karolinska Surgical Extent and Complexity Score (K-SECS)

AbstractBackground Cytoreductive surgery is central to the management of advanced ovarian cancer. As the extent of surgery varies widely, assessment of postoperative risk is challenging. The Karolinska Surgical Extent and Complexity Score (K-SECS) was developed to quantify surgical extent and has previously been associated with survival. This study evaluated whether K-SECS is also associated with major postoperative complications (MPC). Methods We conducted an observational study using two Swedish databases (2009–2023) including women with FIGO stage III–IV ovarian cancer undergoing cytoreductive surgery. K-SECS was classified as Intermediate (0–9), High (10–18), or Very High (≥19). The primary outcome was MPC (Clavien–Dindo grade ≥ III). Multivariable logistic regression adjusted for relevant covariates was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs). Results A total of 399 patients were included; 25% experienced an MPC. The risk of MPC increased with increasing surgical extent: 15% (Intermediate), 33% (High), and 52% (Very High). Compared with Intermediate scores, High (OR 2.69, 95% CI 1.62–4.52) and Very High K-SECS (OR 5.92, 95% CI 2.03–18.3) were associated with higher odds of MPC. Absolute adjusted risk differences confirmed a clinically meaningful stepwise increase in morbidity across K-SECS categories, with a 34% higher risk in the Very High versus Intermediate group (95% CI 11–57). Conclusion K-SECS is associated with MPC. When considered alongside its previously demonstrated association with survival, K-SECS may support a more structured assessment of the balance between oncologic benefit and surgical risk in advanced ovarian cancer.