Survival Impact of Adjuvant Chemotherapy for Resected Locally Advanced Rectal Adenocarcinoma.
Recent data has created uncertainty regarding the benefit of adjuvant fluoropyrimidine-containing chemotherapy following preoperative chemoradiotherapy and surgical resection for locally advanced rectal cancer (LARC). In particular, patients with a pathologic complete response (pCR) may derive no benefit from adjuvant chemotherapy.



This is a retrospective analysis of patients with LARC, diagnosed between January 1, 2003 and December 31, 2014 at 3 Melbourne health services. Patients were identified from the Australian Comprehensive Cancer Outcomes and Research Database, where a defined data set is prospectively collected on consecutive patients. Patient demographics, pCR rates, postoperative treatment, recurrence, and survival were analyzed.



A total of 717 patients with LARC were identified, of whom 555 (77%) had received preoperative long-course chemoradiation followed by surgery. Four hundred fifty-two of 555 patients (81%) subsequently received adjuvant fluoropyrimidine-based chemotherapy. At a median follow-up of 45.9 months, 95 (21%) patients in the adjuvant chemotherapy group and 20 (19%) in the surveillance group had relapsed. Five-year relapse-free survival was 77% in the adjuvant chemotherapy group and 71% in the surveillance group with no significant difference on univariate analysis (hazard ratio [HR], 0.93; 95% confidence interval [CI], 0.58-1.51; P = .780). No significant impact on relapse-free survival was seen for either pCR or non-pCR patients. Five-year overall survival (OS) was 85% in the adjuvant chemotherapy group and 74% in the surveillance group with a nonsignificant trend towards OS benefit (HR, 0.62; 95% CI, 0.37-1.05; P = .074). A significant OS benefit favoring adjuvant chemotherapy was seen in the non-pCR subset of patients (HR, 0.49; 95% CI, 0.28-0.86; P = .014).



A high proportion of patients in this routine practice cohort received adjuvant chemotherapy following preoperative treatment and surgery for LARC. Adjuvant chemotherapy administration was associated with a significant improvement in 5-year OS only in the patients with a non-pCR.
Department of Medical Oncology, Eastern Health, Box Hill, Australia.
Rebecca Y
RY
Tay
Department of Surgery, Eastern Health, Box Hill, Australia.
Murtaza
M
Jamnagerwalla
Department of Surgery, Eastern Health, Box Hill, Australia.
Malcolm
M
Steel
Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia; University of Melbourne, Melbourne, Australia.
Hui-Li
HL
Wong
Department of Medical Oncology, Eastern Health, Box Hill, Australia; Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia.
Joseph J
JJ
McKendrick
Western Health, Footscray, Australia.
Ian
I
Faragher
Western Health, Footscray, Australia.
Suzanne
S
Kosmider
The Royal Melbourne Hospital, Parkville, Australia.
Ian
I
Hastie
The Royal Melbourne Hospital, Parkville, Australia.
Jayesh
J
Desai
The Royal Melbourne Hospital, Parkville, Australia.
Mark
M
Tacey
Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia; University of Melbourne, Melbourne, Australia; Western Health, Footscray, Australia; The Royal Melbourne Hospital, Parkville, Australia.
Peter
P
Gibbs
Department of Medical Oncology, Eastern Health, Box Hill, Australia; Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia; Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia. Electronic address: Rachel.Wong@monash.edu.
Rachel
R
Wong
D000230:Adenocarcinoma / Q000473:pathology / Q000628:therapy*; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage*; D001315:Australia; D017024:Chemotherapy, Adjuvant / Q000379:methods; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009364:Neoplasm Recurrence, Local; D016016:Proportional Hazards Models; D012004:Rectal Neoplasms / Q000473:pathology / Q000628:therapy*; D012189:Retrospective Studies; D015996:Survival Rate
Overall survival; Pathologic complete response; Postoperative chemotherapy; Preoperative chemoradiotherapy; Surgery