A phase II study of cetuximab, capecitabine and radiotherapy in neoadjuvant treatment of patients with locally advanced resectable rectal cancer.

BACKGROUND

Neoadjuvant chemoradiotherapy (CRT) reduces local tumor recurrence in locally advanced rectal cancer (LARC). This phase II study assessed neoadjuvant cetuximab with capecitabine-based CRT in LARC.

METHODS

Patients with stage II/III LARC received capecitabine 1250 mg/m(2) twice daily for 2 weeks followed by intravenous cetuximab 400 mg/m(2) at week 3, then weekly intravenous 250 mg/m(2) cetuximab plus CRT including capecitabine 825 mg/m(2) twice daily (including weekends during radiotherapy) with radiotherapy of 45 Gy (25 x 1.8 Gy), 5 days a week for 5 weeks. Total mesorectal excision was scheduled 4-6 weeks following completion of CRT. The primary endpoint was pathological complete response (pCR).

RESULTS

Thirty-seven patients were eligible for safety and efficacy. TMN staging at baseline was: T4N2, 11%; T3N2, 40%; T2N2, 3%; T3N1, 35%; T2N1, 3% and T3N0 8%. The most common adverse events included, grade 1/2 acneiform skin rash (86%), and grade 3 radiodermatitis, (16%), diarrhea (11%) and hypersensitivity (5%). pCR was achieved in 3 patients (8%). Overall-, T- and N-downstaging rates were 73%, 57% and 81% respectively. Total sphincter preservation rate was 76%, and 53% in 17 patients whose tumors were located within 5 cm from the anal verge. Non-fatal perioperative complications occurred in 13 patients (35%) with delayed wound healing occurring in 6 patients (16%). One death was recorded due to sepsis following colonic necrosis.

CONCLUSION

Neoadjuvant cetuximab with capecitabine-based CRT is tolerable in patients with resectable LARC. Whilst the pCR rate was similar to recent reports, a high pathological downstaging rate was achieved.