In the nutritional support of patients with cancer, which of the following statements is/are true?
A. Nutritional support benefits the patient s lean body mass but does not enable the tumor to grow B. In experimental animals, the growth of implanted tumors is directly proportional to the amount of calories and protein supplied. C. Prospective randomized trials of nutritional support utilizing chemotherapy and radiation therapy have revealed benefits to patients receiving total parenteral nutrition D. Studies of nutritional support for patients with cancer about to undergo surgery revealed decreased morbidity and mortality, especially morbidity from sepsis.
In experimental animals, the growth of implanted tumors is directly proportional to the amount of calories and protein supplied.-the problem with the patient with cancer is a very vexing one. clearly, one of the metabolic effects of cancer, cachexia, affects patients in the last quartile of their disease and makes such patients intolerant of chemotherapy, radiation therapy, and, in many cases, operative procedures. total parenteral nutrition (tpn) has been proposed as a means of reversing cachexia and enabling patients to better tolerate surgery, chemotherapy, and radiation therapy. in experimental animals, it is clear that the provision of calories and protein, especially in excessive amounts, is associated with the more rapid growth of tumors and decreased survival, especially in the group that is overfed in the extreme. there is also evidence suggesting that overfeeding, or at least tpn, may result in increased growth (or at least change cell kinetics) in patients who are overnourished with tpn. of the randomized prospective trials that have been carried out, no trial utilizing chemotherapy or radiation therapy has revealed a survival advantage for patients receiving tpn. indeed, in shambergers study, there is a suggestion that the tumor-free interval following treatment of lymphoma may be shorter in patients receiving tpn. in patients undergoing surgery, however, especially those who are severely malnourished (as recently revealed in the va study) or in patients with major procedures such as esophagogastrectomy (as in mullers study), evidence suggests that tpn is beneficial. in a late follow-up in mullers study, there was no apparent increase in recurrence, and the survival rate was the same, despite much higher mortality in the non-tpn group. this suggests that any improved survival following operation may have been offset by an increased late recurrence rate, although it is difficult to reach this conclusion. in summary, for patients with cancer tpn probably nourishes the tumor as well as the host. nonetheless, in severely malnourished patients provision of tpn from 5 to 10 days preoperatively may increase survival and decrease morbidity. overfeeding must be avoided. future studies will undoubtedly reveal that there are certain nutrients that tumors require, which probably should be best avoided.