Therapy of gastrointestinal cancer.

Cancer of the gastrointestinal tract represents a major international health problem. At the present time surgical resection for limited stages of disease represents the only treatment which can consistently provide long-term disease-free survival. Unfortunately, the majority of patients present with either microscopic metastatic disease in distant sites or advanced tumour growth which exceeds the limits of surgical resection. Relatively little progress has been made in the development of effective forms of non-surgical therapy. Gastric cancer, however, has been demonstrated to have greater sensitivity to forms of chemotherapy and radiation therapy than was previously appreciated. During the past decade, more effective forms of palliative therapy have been developed for patients with advanced disease, and approximately 15% of the cases with locally unresectable gastric cancer can now achieve long-term disease-free survival with combined forms of treatment. Unfortunately, similar progress has not been made in the management of pancreatic cancer or advanced colon cancer. The recent experience of the Gastrointestinal Tumor Study Group with the use of combined radiotherapy and chemotherapy for rectal cancer has demonstrated that improved disease-free survival can be achieved for patients with Dukes B and C disease. Overall, the current limited efficacy and considerable toxicity of conventional therapies strongly support the development of new approaches to the management of gastrointestinal cancer; this includes the exploitation of the recent progress that has been made in our understanding of cell proliferation and cell cycle control, and the importance of oncogenes and growth factors for regulation of these processes. Ultimately, our understanding of the molecular genetics of gastrointestinal cancer might allow for development of more effective means for both prevention and treatment at the molecular level.