Introduction: Immune checkpoint inhibitors (ICI) can result in a durable response in patients with deficient DNA mismatch repair colorectal cancer (dMMR). Oligoprogressive disease is increasingly becoming a clinical dilemma encountered by surgical oncologists and it is unclear if there is a role for resection.
Methods: We retrospectively report a series of patients with metastatic colorectal cancer and dMMR treated with ICI who developed oligoprogression and underwent resection. We evaluated clinical factors, radiographic findings, patient outcomes, and change in circulating tumor DNA (ctDNA) post resection.
Results: Four female patients, with a median age of 67.5 years underwent resection of oligoprogressive disease. All of the patients received a median of 8 cycles of oxaliplatin-based adjuvant therapy. Following initial resection, patients developed metastatic disease at a median of 8 months from initial diagnosis. Median time to development of oligoprogression after ICI initiation was 4-5 months. A positron emission tomography (PET) scan in three patients demonstrated PET avid oligoprogressive disease and non-avid, non-progressive residual disease. Surgical intervention included abdominal wall resections in two patients and multi-visceral resection in the other two patients. All patients had viable disease on pathological evaluation. Three patients had a negative ctDNA following resection.
Conclusion: In well selected patients resection of oligoprogressive disease in dMMR colorectal cancer patients treated with ICI can result in durable disease control. Postoperative ctDNA levels suggest that in some patients oligoprogression represents local failure. Preoperative PET/CT scan should be considered in all patients to assess for tumor viability.
