Colorectal cancer: intrinsic characteristics modulate cancer energy expenditure and the risk of cachexia.
OBJECTIVE
To conduct a prospective longitudinal study in colorectal cancer (CRC) patients: 1) to evaluate resting energy expenditure (REE), weight/dietary intake changes, and response to treatment, taking into consideration cancer stage and histology; 2) to determine their potential interrelations; and 3) to quantify the relative contributions to REE of cancer/nutrition/treatment.


METHODS
101 CRC patients proposed for neoadjuvant radiotherapy (RT) were evaluated before and after RT: REE (indirect calorimetry measurements), percentage of weight loss, usual diet (diet history), current diet (24 hour recall), and treatment response.


RESULTS
REE was higher in Stages III/IV versus I/II, at the RT onset (p < 0.002) and end (p = 0.02), and in moderately/poorly/undifferentiated cancers vs well differentiated (onset, p < 0.001) and (RT end, p = 0.01); weight/intake reductions were also greater in Stages III/IV versus I/II (p < 0.01) and in moderately/poorly/undifferentiated cancers versus well differentiated (p < 0.02). According to patients' response to treatment, REE was increased in Stage III/IV (p < 0.005) and Grade 2/3 histology (p < 0.003). In nonresponders, REE increased 7.2 +/- 1.3 kcal/kg/day and decreased 2.8 +/- 0.4 kcal/kg/day in responders. REE changes were not-significantly influenced by weight/intake. Relative contributions to baseline REE were determined in 25 percent by stage, in 25 percent by histology, in 3 percent by intake and in 4 percent by weight loss. At the end of RT, higher REE was attributed in 26 percent to stage, in 27 percent to histology, in 30 percent to nontreatment response, in 9 percent to intake, and in 8 percent to weight loss.


CONCLUSIONS
In this CRC patient population, higher metabolic rates were mainly determined by the tumor burden and aggressiveness in association with response to treatment clearly disclaiming the effect of weight loss and/or dietary intake reductions.
Instituto de Medicina Molecular, Unidade de Nutrição e Metabolismo, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal. p.ravasco@fm.ul.pt
Paula
P
Ravasco
Isabel
I
Monteiro-Grillo
Maria
M
Camilo
D001481:Basal Metabolism; D002100:Cachexia / Q000453:epidemiology*; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology* / Q000628:therapy; D004734:Energy Metabolism; D006801:Humans; D008137:Longitudinal Studies; D009367:Neoplasm Staging; D009752:Nutritional Status; D011446:Prospective Studies; D016896:Treatment Outcome