title: The survival impact of delayed surgery and adjuvant chemotherapy on stage II/III rectal cancer with pathological complete response after neoadjuvant chemoradiation.
abstract: Neoadjuvant concurrent chemoradiation (CCRT) is standard treatment for clinical stage II/III rectal cancers. However, whether patients with pathological complete response (pT0N0, pCR) should receive adjuvant chemotherapy and whether delayed surgery will influence the pCR rate remains controversial. A nationwide population study was conducted using the Taiwan Cancer Registry Database from January 2007 to December 2013. Kaplan-Meier survival analysis was performed. Cox proportional hazards models were used to estimate multivariate adjusted hazard ratios (HR) and 95% confidence intervals (95% CI). Of the 1,914 patients who received neoadjuvant CCRT, 259 (13.6%) achieved pCR and had better survival (adjusted HR: 0.37, 95% CI: 0.24-0.58; p < 0.001). The cumulative rate of pCR rose up to 83.4% in the 9th week and slowly reached a plateau after the 11th week. Among the patients with pCR, those who received adjuvant chemotherapy had no survival benefits compared to those without adjuvant chemotherapy (adjusted HR: 0.72, 95 CI: 0.27-1.93; p = 0.52). By subgroup analysis, those younger than 70-year old and received adjuvant chemotherapy had better survival benefit than those without adjuvant chemotherapy (adjusted HR: 0.19, 95% CI: 0.04-0.97; p = 0.046). Delayed surgery by 9-12 weeks after the end of neoadjuvant CCRT can maximize the pCR rate, which is correlated with better survival. Adjuvant chemotherapy may be considered in patients with pCR and aged <70-year old, but further prospectively randomized controlled trials are warranted to validate these findings.
authors.affiliation: Department of Hematology and Oncology, Chang-Gung Memorial Hospital, Chia-Yi, 61363, Taiwan.|Graduate Institute of Clinical Medical Sciences, Chang-Gung University, Tao-Yuan, 33302, Taiwan.
authors.forename: Feng-Che
authors.initials: FC
authors.lastname: Kuan
authors.affiliation: Department of Radiation Oncology, Chang-Gung Memorial Hospital, Chia-Yi, 61363, Taiwan.
authors.forename: Chia-Hsuan
authors.initials: CH
authors.lastname: Lai
authors.affiliation: National Institute of Cancer Research, National Health Research Institutes, Miaoli, Taiwan (R.O.C).
authors.forename: Hsiu-Ying
authors.initials: HY
authors.lastname: Ku
authors.affiliation: Department of Hematology and Oncology, Chang-Gung Memorial Hospital, Chia-Yi, 61363, Taiwan.
authors.forename: Chun-Feng
authors.initials: CF
authors.lastname: Wu
authors.affiliation: Division of Colon and Rectal Surgery, Chang-Gung Memorial Hospital, Chia-Yi, 61363, Taiwan.
authors.forename: Meng-Chiao
authors.initials: MC
authors.lastname: Hsieh
authors.affiliation: National Institute of Cancer Research, National Health Research Institutes, Miaoli, Taiwan (R.O.C).
authors.forename: Tsang-Wu
authors.initials: TW
authors.lastname: Liu
authors.affiliation: Division of Colon and Rectal Surgery, Department of Surgery, Chang-Gung Memorial Hospital, Lin-Kou, Taiwan.|Department of Clinical Medical Sciences, Chang-Gung University, Tao-Yuan, 33302, Taiwan.
authors.forename: Chien-Yuh
authors.initials: CY
authors.lastname: Yeh
authors.affiliation: Department of Hematology and Oncology, Chang-Gung Memorial Hospital, Chia-Yi, 61363, Taiwan.|Department of Medicine, Chang-Gung University, Tao-Yuan, 33302, Taiwan.
authors.forename: Kuan-Der
authors.initials: KD
authors.lastname: Lee
mesh_terms: D000368:Aged; D059248:Chemoradiotherapy / Q000379:methods*; D017024:Chemotherapy, Adjuvant / Q000379:methods*; D003710:Demography; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020360:Neoadjuvant Therapy / Q000379:methods*; D016016:Proportional Hazards Models; D012004:Rectal Neoplasms / Q000150:complications / Q000188:drug therapy* / Q000532:radiotherapy* / Q000601:surgery; D012074:Remission Induction; D013624:Taiwan; D013997:Time Factors; D061665:Time-to-Treatment; D016896:Treatment Outcome
keywords: adjuvant chemotherapy; neoadjuvant chemo-radiation; pathological complete response; rectal cancer; survival