ASO Author Reflections: Potential Therapeutic Implications and Prediction of Pathological Complete Response to Systemic Chemotherapy in Colorectal Peritoneal Metastases

Cytoreductive surgery with or without hyperthermic intraperitoneal chemotherapy (HIPEC) is a potentially curative treatment for selected patients with colorectal peritoneal metastases (CPM). Although the exact role of systemic chemotherapy has been questioned, a recent study showed the benefit of adjuvant systemic therapy for isolated, resectable CPM, and the role of neoadjuvant chemotherapy (NACT) is being evaluated in a randomized trial.1,2 Systemic chemotherapy is undoubtedly an important component of the multimodality management of these patients. The pathological response to systemic chemotherapy has prognostic value, as shown in one retrospective study.3 It is likely that many patients who are “cured” are those who have pathological complete response (pCR) or near-complete response to NACT, and that these patients have a marginal or no benefit from HIPEC. pCR, however, remains a largely ignored factor, though systemic therapies are increasingly being used to treat these patients. The main disadvantage is that the response is known only at time of surgery, which precludes use of pCR to select patients for surgery. …