Improving colorectal cancer care: treatment and outcomes of patients with colorectal cancer

Abstract

Survival of patients with colorectal cancer improved markedly over the past decades, as a result of advances in screening, staging procedures, treatment, and surveillance. However, still about 20% of patients with colorectal cancer develop metachronous metastases and 20% of all patients with colorectal cancer have metastatic disease at diagnosis. Several treatment modalities, such as total mesorectal excision (TME) and preoperative (chemo)radiotherapy for rectal cancer, as well as adjuvant chemotherapy for stage III colon cancer, have been studied extensively and showed to improve cancer-related outcomes. On the contrary, the effectiveness of other treatment modalities including adjuvant chemotherapy for rectal cancer and for stage II colon cancer, and surgery of the primary tumour in incurable metastatic colorectal cancer are still subject of debate. Moreover, there is considerable short-term and long-term morbidity after (chemo)radiotherapy or surgery which should be taken into account. Further defining optimal treatment strategies is therefore of great importance. This thesis focused on improving evidence for treatment modalities that are currently subject of debate for patients with colorectal cancer. This was done using data from randomised controlled trials as well as cancer registry data.