Metastatic Colorectal Cancer Treatment and Survival: the Experience of Major Public Hospitals in South Australia Over Three Decades

Background: Registry data from four major public hospitals indicate trends over three decades from 1980to 2010 in treatment and survival from colorectal cancer with distant metastases at diagnosis (TNM stageIV). Materials and
Methods: Kaplan-Meier product-limit estimates and Cox proportional hazards modelsfor investigating disease-specific survival and multiple logistic regression analyses for indicating first-roundtreatment trends.
Results: Two-year survivals increased from 10% for 1980-84 to 35% for 2005-10 diagnoses.Corresponding increases in five-year survivals were from 3% to 16%. Time-to-event risk of colorectal cancerdeath approximately halved (hazards ratio: 0.48 (0.40, 0.59) after adjusting for demographic factors, tumourdifferentiation, and primary sub-site. Survivals were not found to differ by place of residence, suggestingreasonable equity in service provision. About 74% of cases were treated surgically and this proportion increasedover time. Proportions having systemic therapy and/or radiotherapy increased from 12% in 1980-84 to 61%for 2005-10. Radiotherapy was more common for rectal than colonic cases (39% vs 7% in 2005-10). Of thecases diagnosed in 2005-10 when less than 70 years of age, the percentage having radiotherapy and/or systemictherapy was 79% for colorectal, 74% for colon and 86% for rectum (&RS)) cancers. Corresponding proportionshaving: systemic therapies were 75%, 71% and 81% respectively; radiotherapy were 24%, 10% and 46%respectively; and surgery were 75%, 78% and 71% respectively. Based on survey data on uptake of offeredtherapies, it is likely that of these younger cases, 85% would have been offered systemic treatment and amongrectum (&RS) cases, about 63% would have been offered radiotherapy.
Conclusions: Pronounced increases insurvivals from metastatic colorectal cancer have occurred, in keeping with improved systemic therapies andsurgical interventions. Use of radiotherapy and/or systemic therapy has increased markedly and patterns ofchange accord with clinical guideline recommendations.