Effect of Adjuvant Chemotherapy on Survival of Patients With Stage III Colon Cancer Diagnosed After Age 75 Years

Abstract

A B S T R A C T PurposeFew 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. MethodsA total of 5,489 patients Ն 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. ResultsUse 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 PSmatched 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. ConclusionThe noninvestigational experience suggests patients with stage III CC Ն 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.

Characteristics Affecting Survival after Locally Advanced Colorectal Cancer in Quebec

“…Because no statistical adjustment was made for the underlying health and functional status of the patients, that finding should be interpreted to reflect both the effect of guideline adherence and the effect of the underlying general health and functioning in those patients, such that those receiving guideline-adherent treatment were also more likely to be in better overall health than patients not so treated 21,24,25 . Furthermore, some overestimation of the effect of guideline adherence could result from the intrinsic nature of the rer measure, in which the population-matched mortality rates used to estimate the expected-hazard death rates do not account for differences in general health and functioning because the rates are matched solely on age, sex, and calendar year.…”

“…Furthermore, some overestimation of the effect of guideline adherence could result from the intrinsic nature of the rer measure, in which the population-matched mortality rates used to estimate the expected-hazard death rates do not account for differences in general health and functioning because the rates are matched solely on age, sex, and calendar year. The cancer-specific mortality reduction associated with guideline adherence in lacrc patients generally ranges from 30% to 40% in observational studies, and most of those studies are also affected by some degree of confounding by underlying health status 2,21,[25][26][27][28] . A landmark pooled analysis of trials of fluorouracil-based adjuvant chemotherapy in stage iii colon cancer patients published in 2001 reported a 24% overall mortality reduction across all age groups 29 .…”

VATE: VAlidation of high TEchnology based on large database analysis by learning machine

“…Given the differences between patients recruited to trials and those seen in routine practice, increased toxicity might also be expected when the results of RCTs are applied to routine practice. Considering that, observational studies are essential to identify whether practice has changed appropriately, to document harms of therapy in a wider population, in patients of different age and with different comorbidities and to determine whether patients in routine practice are reaching the expected outcomes [17][18][19] with future science group www.futuremedicine.com the expected toxicity. However, when multiples RCTs within one tumor type and comparing over decades and worldwide different treatment agents, classes and subpopulations, are observed in a pooled analysis [20][21][22], the best of both research regimens is reached: high amount of patient's variability with high data quality.…”

Adjuvant and Neoadjuvant Treatment for Rectal Cancer, Colon Cancer, and Non-Small-Cell Lung Cancer in Older Patients

“…Notably, studies examining adjuvant chemotherapy for colon cancer demonstrated survival benefits for patients 75 years of age and older 5 , and studies examining non-small-cell lung cancer showed that patients 65 years of age and older receiving chemotherapy can experience improved survival with acceptable toxicity 6 . Similarly, older patients with stage ii or iii rectal cancer who are fit enough for surgery are generally fit enough for preoperative neoadjuvant radiation therapy, and studies have demonstrated tolerability and response rates similar to those seen in younger patients 7 .…”