Glucose metabolism and colorectal carcinoma

We evaluated nine patients with colorectal cancer and six control patients in a postabsorptive state in an attempt to define the effect of cancer on glucose turnover, oxidation, recycling, and resting metabolic expenditures (RME). The glucose kinetics were determined using a double-labeled [U-14C] glucose and [6-3H] glucose, and energy expenditures were measured by indirect calorimetry. In addition, we also measured the same parameters in the cancer patient group on a total parenteral nutrition (TPN)-glucose system on the fourth day before and on the fifth day after removal of tumor. In the postabsorptive state, glucose turnover and oxidation rates were similar in the cancer and control group; however, the mean glucose pool size of the cancer group was 47% larger than the control group and was statistically significant (P = .05). Glucose recycling was also two times the control group and was statistically significant (P = .05). The recycling of glucose, both preoperatively and postoperatively, continued in the face of infused glucose; however, the rate was suppressed compared with the fasting cancer group. Postabsorptive RME of the cancer group did not differ from those predicted by the Harris-Benedict equation. Following a 4-day infusion of TPN-glucose that supplied a mean of two times the patients' energy needs, the preoperative cancer group showed a mean increase in RME of 25.6% and a 31.58% increase on the fifth postoperative day of TPN-glucose, presumably due to increased lipogenesis and to a much lesser extent from the increased protein synthesis (4 g positive N balance).(ABSTRACT TRUNCATED AT 250 WORDS)