Feasibility of modified short-course radiotherapy combined with a chemoradiosensitizer for T3 rectal cancer.

BACKGROUND

5-Fluorouracil-based chemotherapy is considered to be a radiosensitizer; however, conventional short-course radiotherapy combined with chemotherapy is generally thought to not be feasible because of the prevalence of side effects.

OBJECTIVE

The aim of this study was to evaluate the feasibility of modified short-course radiotherapy combined with a chemoradiosensitizer for T3 rectal cancer.

DESIGN AND SETTINGS: This study was retrospective in nature and used a prospectively collected database.

PATIENTS: Patients with T3 rectal cancer located below the peritoneum reflection were selected.

INTERVENTIONS: A total dose of 25 Gy of radiotherapy was administered in 10 fractions of 2.5 Gy each for 5 days. Radiotherapy was performed with S-1 as a radiosensitizer from day 1 to day 10. Surgery was targeted to be performed 4 weeks after radiotherapy.

MAIN OUTCOME MEASUREMENTS: The morbidity, sphincter-preserving rate, anal function, and long-term outcomes were assessed.

RESULTS

All patients (n = 170) completed the radiotherapy regimen and 166 (97.6%) completed the combination regimen with chemotherapy. A total of 149 patients (87.6%) had sphincter-preserving surgery (double stapling technique (DST), 58 patients; intersphincteric resection (ISR), 91 patients), and postoperative complications were relatively mild (anastomotic leakage, 15.4%; intra-abdominal infection, 8.2%). Among those undergoing sphincter preserving surgery, the 5-year local relapse-free survival rate was 94.3% in the DST group, and 89.8% in the ISR group. With respect to the anal function, the Wexner score the first year after stoma closure for the double-stapling technique group was 6 and that for intersphincteric resection was 15; however, the score for the intersphincteric resection group was improved to 8 at 4 years after stoma closure.

LIMITATIONS: This study had limitations because it was an uncontrolled, 1-arm, retrospective review with a small sample size.

CONCLUSIONS

Modified short-course radiotherapy combined with chemoradiosensitizer is a feasible approach for treating T3 rectal cancer. With the use of the short-course approach, efforts to reduce the incidence of side effects by appropriately prolonging the waiting period enable the administration of combination treatment with short-course radiotherapy and chemotherapy.