Obesity in Childhood Spells Cancer Risks In Adulthood
Rising rates of childhood obesity could spell worse cancer outcomes for the next generation of adults.
Experts at the 2010 Digestive Disease Week, held in New Orleans, presented several studies linking childhood obesity to higher cancer rates, as well as worse outcomes for obese adult patients with cancer.
“This is part of the more complicated story about the epidemic of obesity,” said Craig P. Fischer, MD, MPH, assistant professor of surgery of Methodist Hospital in Houston, as he moderated a press conference where the studies were presented.
In a study of more than 1,800 average-risk patients who underwent a standard screening colonoscopy, obese adults who were overweight or obese in childhood and/or early adulthood were found to be at twice the risk for developing colon cancer compared with adults with consistently normal weight.
A second study showed that pancreatic cancer patients who had more intra-abdominal fat had between 30% and 400% increase in mortality, based on computed tomography scan assessments of 61 patients. Another similar study showed that patients with intra-abdominal fat were twice as likely to experience complications from surgery for rectal cancer than patients with small waists (see article on page 18).
Obesity’s effect on cancer risk and outcomes is so profound that screening recommendations could require tightening if childhood obesity continues unchecked, said experts.
“Given the continued rise in early-onset obesity, especially in minority populations, there is a need for interventions and lifestyle modifications earlier in life to help lessen this serious health risk later in life,” said Fritz Francois, MD, assistant professor of medicine at NYU’s Langone Medical Center in New York City, and author of one of the studies.
The study by Dr. Francois and his colleagues showed a clear link between a high body mass index (BMI) in childhood and colon cancer in adulthood. In a study of 1,865 adults referred for screening colonoscopy, investigators found a significant prevalence of polyps in patients who had been consistently overweight or obese (27%), especially compared with patients with consistently normal BMI (13%) and overweight BMIs at present (19%).
The increase in BMI from early adulthood remained a significant predictor of colon pathology after controlling for age, sex, current BMI, birth in the United States and red meat consumption (odds ratio, 1.8; 95% confidence interval [CI], 1.02-3.23; P=0.04).
“Our findings suggest that the chronicity of obesity is a significant risk factor for developing colon cancer,” said Dr. Francois.
The study cohort had a mean age of 57(±9) years and was 57% female. They were considered of average risk for colon cancer. At the time of colonoscopy, BMI was normal in 33% of patients, whereas 39% were overweight and 23% were obese. Past BMIs were estimated from patients’ recollections of body type and clothing size at ages 10 and 20.
The report also found ethnic minorities to be particularly at risk for weight gain. Hispanics had the highest rate of prevalence of increased BMI from normal at age 20 to abnormal at screening colonoscopy (61%), followed by blacks (50%), whites (46%) and Asians (7%)(P=0.004).
Other studies found that although obesity negatively impacts cancer outcomes, the location of the extra fat, rather than the amount, is a critical factor. Investigators from Baylor College of Medicine in Houston, showed that the more intra-abdominal fat that pancreatic cancer patients had, the worse their prognosis, although BMI itself did not significantly predict survival.
The finding suggests that visceral fat may be a useful tool to risk-stratify patients, said study co-author Courtney Balentine, MD, a research fellow in the Department of Surgery at Baylor.
“BMI isn’t a very good definition of what it actually means to be obese,” she said, citing the example of Arnold Schwarzenegger as a person with a high BMI but not overweight. “When you look at survival in terms of the amount of intra-abdominal fat, however, we found that the more fat there is, the worse patients do.”
The findings were based on a retrospective review of 61 patients who had a Whipple procedure for exocrine pancreatic adenocarcinoma between 2000 and 2009.
After adjusting for age and perineural invasion status, preoperative BMI was not a significant predictor of overall survival. Intra-abdominal fat, however, had a marked association with survival. Relative to patients with the lowest quantity of intra-abdominal fat, those in the second quartile had a fourfold increase in the likelihood of death (hazard ratio [HR], 4.018; 95% CI, 1.099-14.687; P<0.035).
Patients in the third and fourth quartiles also had higher mortality rates, although neither was statistically significant (HR, 2.12; 95% CI, 0.278-16.222; P<0.468 for the third quartile; and HR, 1.354; 95% CI, 0.296-6.190; P<0.696 for the fourth).
The investigators are unsure exactly why the visceral fat increases mortality risks. Based on results of previous studies, they believe the reason is biologic rather than a technical issue related to surgery.
Another study from the same group of investigators showed that patients with a waist circumference of 45 inches or more were three times more likely to experience surgical site infections and twice as likely to require reoperation for rectal cancer.
The study findings may lead to more individualized approaches for chemotherapy, surgery and medications, Dr. Balentine said. “Maybe we can do something different about the surgery or develop specific weight-loss programs for specific medications targeting intra-abdominal fat to cut down on the risk and help patients live longer after surgery,” she said.
The original article appeared in General Surgery News
ISSUE: SEPTEMBER 2010 | VOLUME: 37:09