Long-term results of a phase 2 study of neoadjuvant chemotherapy with molecularly targeted agents for locally advanced rectal cancer

• Published in: International journal of clinical oncology 2023-03, Vol.28 (3), p.392-399
• Main Authors: Aoyama, Ryuhei, Hida, Koya, Hasegawa, Suguru, Yamaguchi, Takashi, Manaka, Dai, Kato, Shigeru, Yamada, Masahiro, Yamanokuchi, Satoshi, Kyogoku, Takahisa, Kanazawa, Akiyoshi, Kawada, Kenji, Sakamoto, Takashi, Goto, Saori, Sakai, Yoshiharu, Obama, Kazutaka
• Format: Article
• Language: English
• Subjects: Antineoplastic Agents - therapeutic use; Antineoplastic Combined Chemotherapy Protocols - therapeutic use; Bevacizumab; Cancer; Cancer Research; Chemotherapy; Colorectal cancer; Fluorouracil - therapeutic use; Follow-Up Studies; Humans; K-Ras protein; Medical prognosis; Medicine; Medicine & Public Health; Neoadjuvant Therapy; Neoplasm Recurrence, Local - drug therapy; Neoplasm Recurrence, Local - genetics; Neoplasm Recurrence, Local - pathology; Neoplasm Staging; Oncology; Original Article; Prospective Studies; Proto-Oncogene Proteins p21(ras) - genetics; Radiation therapy; Rectal Neoplasms - pathology; Rectum; Surgical Oncology; Survival
• ISSN: 1341-9625; 1437-7772
• DOI: 10.1007/s10147-023-02291-4

Background We previously reported the feasibility and efficacy of neoadjuvant chemotherapy without radiotherapy for locally advanced rectal cancer. Here, we report the results of a long-term follow-up study. Methods This was a multi-institutional, prospective phase 2 study of patients with locally advanced rectal cancer. Patients received neoadjuvant chemotherapy with molecularly targeted agents before undergoing total mesorectal excision. Six cycles of modified FOLFOX (mFOLFOX6) with bevacizumab were administered to KRAS-mutant patients, and mFOLFOX6 with cetuximab was administered to KRAS-wild-type patients. Here, we report the secondary end points of overall survival, relapse-free survival, and local recurrence rate. Results Sixty patients were enrolled in this study. R0 resection was achieved in 98.3% (59/60) patients, and pathological complete response was achieved in 16.7% (10/60) patients. After a median follow-up of 5.4 years, the 5 year overall survival was 81.6%, the 5 year relapse-free survival was 71.7%, and the 5 year local recurrence rate was 12.6%. None of the patients who achieved pathological complete response developed recurrence within 5 years. Conclusions The use of molecularly targeted agents in the neoadjuvant setting for locally advanced rectal cancer has an acceptable prognosis.