Colorectal cancer is the third most common malignancy in the developed countries, and about a quarter of people present with intestinal obstruction or perforation. Risk factors for colorectal cancer are mainly dietary and genetic. Overall 5-year survival is about 50%, with half of people having surgery experiencing recurrence of the disease.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments for colorectal cancer? We searched: Medline, Embase, The Cochrane Library, and other important databases up to August 2008 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
We found 57 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
In this systematic review we present information relating to the effectiveness and safety of the following interventions: adjuvant systemic chemotherapy, preoperative radiotherapy, and routine intensive follow-up.
Colorectal cancer is the third most common malignancy in the developed world, and about a fifth of people present with intestinal obstruction or perforation.
Risk factors for colorectal cancer are mainly dietary and genetic.Overall 5-year survival is about 50%, with half of people having surgery experiencing recurrence of the disease.
Adjuvant systemic chemotherapy reduces mortality compared with surgery alone in people who have Dukes' C colorectal cancer. We don't know whether adjuvant systemic chemotherapy improves mortality compared with surgery alone in people with Dukes' B colorectal cancer.
It has been suggested that people with high-risk Dukes' B may derive some benefit with adjuvant systemic chemotherapy compared with surgery alone. However, we found no direct evidence on this group.We found some evidence that oral fluoropyrimidines (with or without leucovorin) may be as effective as intravenous fluorouracil (with or without leucovorin) regimens at reducing mortality. The addition of oxaliplatin to fluorouracil plus leucovorin improves disease-free survival at 3 and 4 years compared with fluorouracil plus leucovorin alone in people with Dukes' B or C colon cancer.Adding irinotecan to fluorouracil plus leucovorin does not reduce mortality any more than fluorouracil plus leucovorin alone in people with Dukes' C colorectal cancer and increases toxic effects.
Preoperative radiotherapy may modestly reduce local tumour recurrence and mortality compared with surgery alone in people with rectal cancer.
Preoperative radiotherapy may reduce local recurrence compared with postoperative radiotherapy. There may be no difference in overall survival between preoperative and postoperative radiotherapy.
Routine intensive follow-up may reduce the time to detection of recurrence and may increase survival compared with less-intensive follow-up in people with colorectal cancer.