Effect of adjuvant chemotherapy on survival of patients with stage III colon cancer diagnosed after age 75 years.
OBJECTIVE
Few patients 75 years of age and older participate in clinical trials, thus whether adjuvant chemotherapy for stage III colon cancer (CC) benefits this group is unknown.


METHODS
A total of 5,489 patients ≥ 75 years of age with resected stage III CC, diagnosed between 2004 and 2007, were selected from four data sets containing demographic, stage, treatment, and survival information. These data sets included SEER-Medicare, a linkage between the New York State Cancer Registry (NYSCR) and its Medicare programs, and prospective cohort studies Cancer Care Outcomes Research and Surveillance Consortium (CanCORS) and the National Comprehensive Cancer Network. Data sets were analyzed in parallel using covariate adjusted and propensity score (PS) matched proportional hazards models to evaluate the effect of treatment on survival. PS trimming was used to mitigate the effects of selection bias.


RESULTS
Use of adjuvant therapy declined with age and comorbidity. Chemotherapy receipt was associated with a survival benefit of comparable magnitude to clinical trials results (SEER-Medicare PS-matched mortality, hazard ratio [HR], 0.60; 95% CI, 0.53 to 0.68). The incremental benefit of oxaliplatin over non-oxaliplatin-containing regimens was also of similar magnitude to clinical trial results (SEER-Medicare, HR, 0.84; 95% CI, 0.69 to 1.04; NYSCR-Medicare, HR, 0.82, 95% CI, 0.51 to 1.33) in two of three examined data sources. However, statistical significance was inconsistent. The beneficial effect of chemotherapy and oxaliplatin did not seem solely attributable to confounding.


CONCLUSIONS
The noninvestigational experience suggests patients with stage III CC ≥ 75 years of age may anticipate a survival benefit from adjuvant chemotherapy. Oxaliplatin offers no more than a small incremental benefit. Use of adjuvant chemotherapy after the age of 75 years merits consideration in discussions that weigh individual risks and preferences.
Dana-Farber Cancer Institute, 44 Binney St, Boston, MA 02115, USA.
Hanna K
HK
Sanoff
William R
WR
Carpenter
Til
T
Stürmer
Richard M
RM
Goldberg
Christopher F
CF
Martin
Jason P
JP
Fine
Nadine Jackson
NJ
McCleary
Jeffrey A
JA
Meyerhardt
Joyce
J
Niland
Katherine L
KL
Kahn
Maria J
MJ
Schymura
Deborah
D
Schrag
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D017024:Chemotherapy, Adjuvant; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000401:mortality* / Q000473:pathology; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008498:Medical Record Linkage; D006278:Medicare; D009367:Neoplasm Staging; D016017:Odds Ratio; D009944:Organoplatinum Compounds / Q000008:administration & dosage; D000077150:Oxaliplatin; D010818:Practice Patterns, Physicians'; D016016:Proportional Hazards Models; D018426:SEER Program; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology
D009944:Organoplatinum Compounds; D000077150:Oxaliplatin