Objectives: To assess the prognostic significance of pathologic tumour response to neoadjuvant chemotherapy.
Methods: Retrospective chart reviews were carried out from 1997 to 2005 to identify ovarian cancer cases treated with neoadjuvant chemotherapy. Pathologic assessments of the extent of: tumour necrosis, fibrosis, macrophage infiltration, and tumour induced inflammation were graded on an ordinal scale of 0 to 2 (none/minimal, moderate, extensive). All pathology slides were reviewed and graded by one gynecologic pathologist. A composite pathologic tumour response score was calculated by summing all above pathologic assessments for each sample. Cox proportional hazard models were built to model time to clinical progression and death using predictor variables of: age, tumour grade, residual disease, and pathologic tumour response score. All p values less than 0.05 were considered to be statistically significant.
Results: Sixty-two cases with available slides for reviews were identified retrospectively. Optimal debulking was achieved in 46 cases (74%). Significant predictors for prolonged progression free survival included: younger age (p=0.05), optimal tumour residual status (p=0.016), and higher composite pathologic tumour response score (HR 0.848, 95% CI 0.742-0.970, p=0.0016). Cox regression modeling revealed only one significant predictive variable of time to disease related death being the composite pathologic tumour response score (HR 0.695, 95% CI=0.515-0.938, p=0.017).
Conclusion: Pathologic assessments of tumour response to chemotherapy are helpful in determining prognosis and could be used to guide subsequent therapeutic decisions. The proposed composite pathologic tumour response score warrants further studies and validation.