Long-term survival outcomes of pseudoadjuvant chemotherapy for resectable metastatic colon cancer: A 14-year single-center experience from King Fahad Medical City, Saudi Arabia.

e15511 Background: Standard treatment for resectable Stage II-III colon cancer typically involves surgery followed by adjuvant chemotherapy for 3-6 months. However, some patients with oligometastatic disease may benefit from pseudoadjuvant chemotherapy, where chemotherapy is administered after curative-intent surgery to metastatic sites to potentially improve outcomes. Methods: This retrospective study analyzed data from 122 consecutive patients with resectable metastatic colon cancer who received pseudoadjuvant chemotherapy at King Fahad Medical City, Saudi Arabia between January 2008 and December 2022. Progression-free survival (PFS) and overall survival (OS) were the primary endpoints. Results: The median age of the patients was 54 years (range: 27-78 years), with 60 (49%) being male. The most common TNM stage at initial diagnosis was IV ( n = 81, 66.4%). The mean follow-up time for patients was 45 months. The most frequent pseudoadjuvant chemotherapy regimen was CapOx ( n = 56, 46%), followed by FOLFOX ( n = 34, 28%). Liver metastasectomy was the most common local treatment for metastatic disease ( n = 77, 63%). Recurrence occurred in 67 patients (54.9%) after pseudoadjuvant chemotherapy. The median PFS was 20 months (95% CI: 12.44-27.56 months). There was no statistically significant difference in PFS between patients who received preoperative chemotherapy and those who did not (p = 0.480). The median OS was 86 months (95% CI: 58.93-113.07 months). No statistically significant associations were found between recurrence and patient gender, initial TNM stage, primary tumor site, or metastatic site (all p-values > 0.05). Conclusions: Our study demonstrated that pseudoadjuvant chemotherapy was associated with improved long-term PFS and OS in patients with resectable metastatic colon cancer. Further prospective studies are warranted to rigorously evaluate the effectiveness of pseudoadjuvant chemotherapy in this patient population.