Does parenteral nutrition increase tumor growth? A review

Total parenteral nutrition (TPN) is a supportive therapy commonly used in clinical oncology, in spite of its possible interference on tumor growth. In fact, studies performed on animals have demonstrated that TPN increases tumor growth and that load and quality of amino acids are probably the main factors involved. In contrast, some authors obtained a decrease in tumor growth using a special amino acids mixture or a TPN formula rich in lipids. However, data collected on animals are not transferable to humans owing to the large difference between tumor-host weight ratio and tumor doubling time. Analysis of the studies on effect of TPN on tumor growth in humans has not demonstrated a bad effect, but the results reported in the literature are limited by the small number of patients, the lack of a sure and reproducible method to analyze tumor growth, and some methodologic defects. In conclusion, it is not evident that TPN is dangerous for cancer patients. However, it may be possible in the future to employ different formulas to improve the host nutritional status and inhibit tumor growth.