Prophylactic hyperthermic ıntraperitoneal chemotherapy for radiologic T4 colorectal cancer: impact on locoregional control

OBJECTIVE: In T4 colorectal cancer, the risk of peritoneal carcinomatosis is high, and the prognosis is poor. The aim of this study was to assess recurrence risk factors, peritoneal recurrence rates, and survival outcomes in patients radiologically diagnosed with T4 tumors who underwent curative surgery with prophylactic hyperthermic intraperitoneal chemotherapy. METHODS: Between January 2018 and December 2022, 38 radiologically diagnosed T4 colorectal cancer patients who underwent prophylactic hyperthermic intraperitoneal chemotherapy were retrospectively analyzed. All patients had R0 resection; those with intraoperative macroscopic peritoneal or distant metastases were excluded. Demographic data, tumor location, histopathology, and pathological T/N stages were recorded. During follow-up, local/distant recurrence, peritoneal carcinomatosis, metastatic sites, and mortality were assessed. RESULTS: The median age was 57 years, and 57.9% were male. The primary tumor originated mainly from the colon (81.6%), with moderately differentiated adenocarcinoma being the most common histology (57.8%). Recurrence occurred in four patients (10.5%): 2 hepatic, 1 pulmonary, and 1 peritoneal, with no local recurrence. One patient (2.6%) died within 90 days; no additional mortality was observed. Median overall survival was 55 months (95%CI 49.82-60.90). Univariate analysis showed no significant association between recurrence and tumor location, differentiation, pT or pN stage, or histologic subtype. CONCLUSION: In cT4 colorectal cancer patients treated with prophylactic hyperthermic intraperitoneal chemotherapy, recurrence was infrequent, peritoneal recurrence was rare, and radiological staging frequently overestimated tumor depth, supporting a potential benefit of prophylactic hyperthermic intraperitoneal chemotherapy in this setting.