Aim: To compare clinicopathological variables, management, and outcome of two cohorts of unselected patients treated for colorectal cancer (CRC) at Christchurch Hospital, New Zealand in 1993-94 and 1998-99.
Methods: Retrospective review from hospital discharge codes, oncology referral database, and histology database. Data was stored in a Microsoft Access database.
Results: 356 patients in 1993-94 and 317 patients in 1998-99 had a confirmed diagnosis of adenocarcinoma of the colon or rectum. At the minimum follow-up time of 42 months, 54% (40% of CRC) of the 356 patients in the first cohort, and 36% (26% of CRC) of the 317 patients in the second cohort had died. The Kaplan-Meier survival curves showed significant improvement in 1998-99 overall, as well as for Dukes stages A plus B, stage C, and stage D disease. Computed tomography (CT) scan-staging increased from 11.3% to 62.8%. On multivariate analysis, cohort, stage, vascular/lymphatic invasion, and elective surgery were independent prognostic factors for disease-specific mortality. Over the 5 years (1993-94 to 1998-99), surgery by consultant increased from 44% to 82%, adjuvant chemotherapy for Dukes stage C increased from 21% to 45%, and chemotherapy for metastatic disease increased from 2.4% to 23% of stage D and from 2.5% to 36.5% of those patients who developed metastases.
Conclusion: The improvement in outcome is attributed to more specialised surgery, more frequent CT scan staging, and greater use of chemotherapy.