Characteristics affecting survival after locally advanced colorectal cancer in Quebec

Abstract

Background: We estimated the relations of sociodemographic, organizational, disease, and treatment variables with the risk of death from colorectal cancer (crc) in a Quebec population-based sample of patients with locally advanced crc (lacrc) who underwent tumour resection with curative intent.

Methods: Information from medical records and administrative databases was obtained for a random sample of 633 patients surgically treated for stages ii-iii rectal and stage iii colon cancer and declared to the Quebec cancer registry in 1998 and 2003. We measured personal, disease, and clinical management characteristics, relative survival, and through multivariate modelling, relative excess rate (rer) of death.

Results: The relative 5- and 10-year survivals in this cohort were 67.7% [95% confidence interval (ci): 65.8% to 69.6%] and 61.2% (95% ci: 58.3% to 64.0%) respectively. Stage T4, stage N2, and emergency rather than elective surgery affected 18%, 24% and 10% of patients respectively. Those disease progression characteristics each independently increased the rer of death by factors of 2 to almost 5. Grade, vascular invasion, and tumour location were also significantly associated with the rer for death. Receiving guideline-adherent treatment was associated with a 60% reduction in the rer for death (0.41; 95% ci: 0.28 to 0.61), an effect that was consistent across age groups. Clear margins (proximal-distal, radial) and clinical trial enrolment were each associated with a nonsignificant 50% reduction in the rer. Of patients less than 70 years of age and 70 years of age and older, 81.3% and 42.0% respectively received guideline-adherent treatment.

Conclusions: This study is the first Quebec population-based examination of patients with lacrc and their management, outcomes, and outcome determinants. The results can help in planning crc control strategies at a population level.

Keywords: Colorectal neoplasms; medical records; multivariate analyses; population-based studies; registries; relative excess hazard rate for death; relative survival; treatment outcomes.

FIGURE 1

Study cohort ascertainment. CRC = colorectal cancer.

FIGURE 2

Relative survival of patients with locally advanced colorectal cancer (rectum stages II–III, colon stage III) who underwent tumour resection with curative intent: (A) all patients diagnosed in 1998 or 2003, (B) all patients according to age at diagnosis, and (C) all patients according to age at diagnosis and adherence to treatment guidelines.

FIGURE 3

Multivariate analysis of the relative excess hazard rate for death during the 60-month period after surgery for patients with locally advanced colorectal cancer [LACRC (rectum stages II–III, colon stage III)] who underwent tumour resection with curative intent. * Difference between the “exposed” and reference categories. ** Overall difference between categories for characteristics classified into 3 or more categories without a category for missing values. RER = relative excess hazard rate for death; CI = confidence interval; PLNR = ratio of the number of invaded to examined nodes; pctl = percentile; NOS = not otherwise specified.