Radiation therapy and combined modality treatment of gastrointestinal carcinomas

Ionizing radiation (IR) is a potent agent in enhancing tumor control of locally advanced cancer and has been shown to improve disease-free and overall survival in several entities. However, the role of radiotherapy (RT) in the treatment of gastrointestinal tumors remains controversial because of the marked radiation sensitivity of neighboring organs frequently compromising application of high doses of ionizing radiation.

The Medline and the Cochrane Library from 1980 until 2005 were searched using subject heading (MeSH) terms including "esophageal neoplasm", "gastric neoplasm", "pancreatic neoplasm" and "rectal neoplasm", in combination with the subheadings "radiotherapy", "chemotherapy". The term, "randomized controlled trial", was used to identify randomized trials. The proceedings of the annual meeting of the American Society for Therapeutic Radiology and Oncology from 1999 to 2004 and the annual meeting of the American Society of Clinical Oncology from 1999 until 2005 were searched. Ongoing trials were identified through the Physician Data Query database (www.cancer.gov/search/clinical_trials).

RT in combination with surgery enhances tumor control of locally advanced cancer disease and has been shown to improve disease-free and overall survival in rectal cancer. In esophageal adenocarcinoma, survival was prolonged with pre-operative chemo-radiation in a meta-analysis. In gastric cancer, post-operative chemo-radiation can be considered after limited lymphadenectomy. Evidence for improving survival remains to be shown for pancreatic cancer and hepatobiliary carcinoma. In colon cancer, post-operative chemotherapy has proven to prolong survival. The impact of RT seems to be most prominent in the pre-operative setting in patients treated with curative intent.

Pre-operative RT or pre-operative chemo-radiation may be considered in individual cases, but should not be used routinely for gastro-intestinal carcinoma, except for rectal carcinoma. In many studies, pre-operative radiotherapy/chemo-radiation yielded promising results and merits validation in large controlled trials.