Adjuvant Chemotherapy After Preoperative Chemoradiation Improves Survival in Patients With Locally Advanced Rectal Cancer.

BACKGROUND

Practice guidelines differ in their support of adjuvant chemotherapy use in patients who received preoperative chemoradiation for rectal cancer.

OBJECTIVE

The purpose of this study was to evaluate the impact of adjuvant chemotherapy among patients with locally advanced rectal cancer who received neoadjuvant chemoradiation and surgery.

DESIGN

This was a retrospective study. Multivariable Cox proportional hazard modeling was used to evaluate the adjusted survival differences.

SETTINGS

Data were collected from the National Cancer Database.

PATIENTS

Adults with pathologic stage II and III rectal adenocarcinoma who received neoadjuvant chemoradiation and surgery were included.

MAIN OUTCOME MEASURES

Overall survival was measured.

RESULTS

Among 12,696 patients included, 4023 (32%) received adjuvant chemotherapy. The use of adjuvant chemotherapy increased over the study period from 23% to 36%. Although older age and black race were associated with a lower likelihood of receiving adjuvant chemotherapy, patients with higher education level and stage III disease were more likely to receive adjuvant chemotherapy (all p < 0.05). At 7 years, overall survival was improved among patients who received adjuvant chemotherapy (60% vs. 55%; p < 0.001). After risk adjustment, the use of adjuvant chemotherapy was associated with improved survival (HR = 0.81 (95% CI, 0.72-0.91); p < 0.001). In the subgroup of patients with stage II disease, survival was also improved among patients who received adjuvant chemotherapy (68% vs 58% at 7 y; p < 0.001; HR = 0.70 (95% CI, 0.57-0.87); p = 0.002). Among patients with stage III disease, the use of adjuvant chemotherapy was associated with a smaller but persistent survival benefit (56% vs 51% at 7 y; p = 0.017; HR = 0.85 (95% CI, 0.74-0.98); p = 0.026).

LIMITATIONS

The study was limited by its potential for selection bias and inability to compare specific chemotherapy regimens.

CONCLUSIONS

The use of adjuvant chemotherapy among patients with rectal cancer who received preoperative chemoradiation conferred a survival benefit. This study emphasizes the importance of adjuvant chemotherapy in the management of rectal cancer and advocates for its increased use in the setting of neoadjuvant therapy. See Video Abstract at http://link.lww.com/DCR/A428.