Adjuvant treatment for resected rectal cancer: impact of standard and intensified postoperative chemotherapy on disease-free survival in patients undergoing preoperative chemoradiation-a propensity score-matched analysis of an observational database.
OBJECTIVE
Adjuvant chemotherapy for resected rectal cancer is widely used. However, studies on adjuvant treatment following neoadjuvant chemoradiotherapy (CRT) and total mesorectal excision (TME) have yielded conflicting results. Recent studies have focused on adding oxaliplatin to both preoperative and postoperative therapy, making it difficult to assess the impact of adjuvant oxaliplatin alone. This study was aimed at determining the impact of (i) any adjuvant treatment and (ii) oxaliplatin-containing adjuvant treatment on disease-free survival in CRT-pretreated, R0-resected rectal cancer patients.


METHODS
Patients undergoing R0 TME following 5-fluorouracil (5FU)-only-based CRT between January 1, 2008, and December 31, 2010, were selected from a nationwide registry. After propensity score matching (PSM), comparison of disease-free survival (DFS) using Kaplan-Meier analysis and log-rank test was performed in (i) patients receiving no vs. any adjuvant treatment and (ii) patients treated with adjuvant 5FU/capecitabine without vs. with oxaliplatin.


RESULTS
Out of 1497 patients, 520 matched pairs were generated for analysis of no vs. any adjuvant treatment. Mean DFS was significantly prolonged with adjuvant treatment (81.8 ± 2.06 vs. 70.1 ± 3.02 months, p < 0.001). One hundred forty-eight matched pairs were available for analysis of adjuvant therapy with or without oxaliplatin, showing no improvement in DFS in patients receiving oxaliplatin (76.9 ± 4.12 vs. 79.3 ± 4.44 months, p = 0.254). Local recurrence rate was not significantly different between groups in either analysis.


CONCLUSIONS
In this cohort of rectal cancer patients treated with neoadjuvant CRT and TME surgery under routine conditions, adjuvant chemotherapy significantly improved DFS. No benefit was observed for the addition of oxaliplatin to adjuvant chemotherapy in this setting.
Department of Surgery, Otto von Guericke University Hospital, Leipziger Str. 44, 39120, Magdeburg, Germany. Benjamin.garlipp@med.ovgu.de.
Benjamin
B
Garlipp
Department of Surgery, Otto von Guericke University Hospital, Leipziger Str. 44, 39120, Magdeburg, Germany.|Institute for Quality Assurance in Surgery, Otto von Guericke University, Leipziger Str. 44, 39120, Magdeburg, Germany.
Henry
H
Ptok
Department of Surgery, Otto von Guericke University Hospital, Leipziger Str. 44, 39120, Magdeburg, Germany.
Frank
F
Benedix
Institute for Quality Assurance in Surgery, Otto von Guericke University, Leipziger Str. 44, 39120, Magdeburg, Germany.
Ronny
R
Otto
Department of Surgery, Otto von Guericke University Hospital, Leipziger Str. 44, 39120, Magdeburg, Germany.
Felix
F
Popp
Institute for Quality Assurance in Surgery, Otto von Guericke University, Leipziger Str. 44, 39120, Magdeburg, Germany.|Department of Surgery, Magdeburg City Hospital, Birkenallee 34, 39130, Magdeburg, Germany.
Karsten
K
Ridwelski
Institute for Quality Assurance in Surgery, Otto von Guericke University, Leipziger Str. 44, 39120, Magdeburg, Germany.
Ingo
I
Gastinger
Department of Surgery, Otto von Guericke University Hospital, Leipziger Str. 44, 39120, Magdeburg, Germany.
Christoph
C
Benckert
Institute for Quality Assurance in Surgery, Otto von Guericke University, Leipziger Str. 44, 39120, Magdeburg, Germany.
Hans
H
Lippert
Department of Surgery, Otto von Guericke University Hospital, Leipziger Str. 44, 39120, Magdeburg, Germany.|Institute for Quality Assurance in Surgery, Otto von Guericke University, Leipziger Str. 44, 39120, Magdeburg, Germany.
Christiane
C
Bruns
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D000069287:Capecitabine / Q000008:administration & dosage; D059186:Chemoradiotherapy, Adjuvant; D016208:Databases, Factual; D018572:Disease-Free Survival; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009944:Organoplatinum Compounds / Q000008:administration & dosage; D000077150:Oxaliplatin; D057216:Propensity Score; D012004:Rectal Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy*; D012189:Retrospective Studies; D055815:Young Adult
D000970:Antineoplastic Agents; D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D000069287:Capecitabine; D005472:Fluorouracil
Adjuvant chemotherapy; Combined modality treatment; Propensity score matching; Rectal cancer; TME surgery