Oxaliplatin Increases Disease-Free Survival In Rectal Cancer: A Single-Institution Experience

The role of oxaliplatin in the management of rectal cancer remains controversial. The PETACC-6, ACCORD, and NSABP R-04 trials did not demonstrate any improvement in disease-free survival (DFS) with the addition of oxaliplatin. However, the recently completed German CAO/ARO/AIO-04 trial showed a significant benefit in DFS with oxaliplatin. We sought to determine whether the addition of oxaliplatin increased DFS for patients with rectal cancer treated at our institution. Seven hundred six patients with cT1-4, any N, M0 biopsy-proven rectal adenocarcinoma who received neoadjuvant radiation therapy (RT) followed by surgical resection at our institution from 2000 to 2015 were included in this retrospective analysis. Data on race, insurance type, clinical/pathological staging, chemotherapy regimen, disease recurrence, last follow-up, and death were collected. Kaplan-Meier methodology was used to calculate DFS and OS. The Wilcoxon rank sum test was used to compare DFS and OS. Cox regression was used for univariate and multivariate analysis Eighty-six percent of patients had locally advanced disease (cT3-4 and/or cN+). One hundred twenty-seven (18%) received no chemotherapy, 264 (37%) received any oxaliplatin-based chemotherapy and 315 (45%) received non-oxaliplatin based chemotherapy. Oxaliplatin regimens included FOLFOX, XELOX, and oxaliplatin with 5-FU. The racial demographics for the oxaliplatin versus non-oxaliplatin chemotherapy groups were comparable (85% white and 15% non-white versus 86% white and 14% non-white, respectively). Insurance type (self-pay, private, or Medicare/Medicaid) was also similar between the two groups. Median follow-up for the cohort was 37.6 months. Overall, 109 patients developed recurrent disease (20 local, 87 distant, 2 local and distant). Patients who received oxaliplatin had a DFS of 71% and 63% at 3 and 5 years, respectively, compared to 61% and 52% for patients who received non-oxaliplatin based chemotherapy (P < 0.0004). Patients who received oxaliplatin had an OS of 92% and 80% at 3 and 5 years, respectively, compared to 82% and 70% for patients who received non-oxaliplatin based chemotherapy (P < 0.007). On univariate and multivariate analysis, oxaliplatin was associated with significant longer DFS (P < 0.0001) but was not found to be associated with increased OS (P = 0.16). In addition, there was no significant association between race or insurance type and DFS. Our study demonstrates that the addition of oxaliplatin increased DFS in rectal cancer patients treated at our institution. Furthermore, our results illustrate that socioeconomic factors such as race and insurance status did not significantly affect whether patients received oxaliplatin or achieved longer DFS. Our results support the German CAO/ARO/AIO-04 trial and suggest that oxaliplatin should be incorporated in the multimodal management of rectal cancer.