Studies of the effects of total parenteral nutrition or enteral nutrition on indicators of tumour growth in cancer patients were eligible for inclusion. The primary outcome of interest was the effect of parenteral or enteral nutrition on tumour growth. Papers that focused on tumour protein metabolism, rather than markers of tumour cell replication, were excluded.
The included studies were conducted in Italy, USA, UK, and China and in most of them the patients had gastrointestinal tumours; in the remaining studies the tumours were located in the head and neck. In most of the studies the patients were malnourished or losing weight and various criteria were used to define malnourished patients. Both the control and parenteral or enteral nutrition regimens varied between studies and the study duration ranged from one to 18 days. A variety of indicators of tumour growth were reported: the deoxyribonucleic acid (DNA) index, ornithine decarboxylase activity, and flow-cytometry DNA distribution; labelling index with tritiated thymidine incorporation and flow cytometry; labelling index with tritiated thymidine or bromodeoxyuridine; and the DNA index, DNA content, and the percentage of cells in S phase.
The authors did not state how many reviewers selected papers for the review.