Gastric cancer in Asia: progress and controversies in surgical management.

Considerable controversy surrounds the management of gastric cancer and this has largely overshadowed recent progress in our understanding of the epidemiology and molecular pathogenesis of the disease, and improvements in diagnostic and staging techniques. Differences identifiable in the molecular pathogenesis of the 'intestinal' and 'diffuse' types of gastric cancer may help to unravel the biological behaviour of variants and ultimately influence therapeutic strategies. Endoscopic ultrasound is well established as being accurate for T staging and the introduction of laparoscopy, with or without ultrasound, is obviating unnecessary laparotomy in non-bleeding, non-obstructed patients. Controversies in surgery encompass the role of laparoscopic surgery in early gastric cancer, the extent of lymphadenectomy including para-aortic nodal dissection, resection of en bloc contiguous organ involvement, pancreatosplenectomy, left upper abdominal evisceration, and modes of reconstruction (pylorus-preserving gastrectomy, pouch formation) to enhance quality of life. Whereas adjuvant chemotherapy does not impact favourably on survival, emphasis has now shifted to neoadjuvant (induction) chemotherapy to downstage the disease. Preoperative regional chemotherapy and intra-operative hyperthermic chemotherapy or irradiation may prove to be of benefit in patients with resectable disease, but some scepticism still exists as to the usefulness of biological response modifiers (e.g. OK432, PSK) for adjuvant treatment. Ethical issues relating to cultural differences in Asia sometimes mitigate against adequate trial design (e.g. a surgery-alone control group or a no adjuvant therapy treatment group may be considered inappropriate) and this has understandably hindered acceptance in Western countries of the value of current management practices in Asia. These issues and the need for ongoing well-conducted randomized trials with prospective subset analysis are now being addressed.