By Molly Brewer, DVM, MD, MS

Professor and Chair, Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, University of Connecticut Health Center, Farmington

Dr. Brewer reports no financial relationships relevant to this field of study.

SYNOPSIS: This study investigated gastric surgery as a prevention for female-associated cancers. Women with a body mass index of 38 kg/m2 who had surgery had an average of 28 kg of weight loss compared to the control group. This resulted in a statistically significant decrease in endometrial cancer.

SOURCE: Anveden A, Taube M, Peltonen M, et al. Long-term incidence of female-specific cancer after bariatric surgery or usual care in the Swedish Obese Subjects Study. Gynecol Oncol 2017;145:224-229.

In the March issue of Gynecologic Oncology, a team from Sweden reported on the long-term incidence of female specific-cancer in women undergoing bariatric surgery. The Swedish Obese Subjects study was a prospective, matched, cohort trial comparing bariatric surgery to the standard of care, which was either medical counseling or no additional treatment. Criteria for inclusion in the study included women between the ages of 37-60 years with a body mass index (BMI) > 38 kg/m2. Several different types of bariatric procedures were performed including gastric banding (18%), vertical banded gastroplasty (68%), and gastric bypass (13%). Women in the gastric surgery group lost a mean of 28 kg at one year, 21 kg at five years, and 21.5 kg at 10 years compared to women in the nonsurgical group, who did not lose weight. Overall, the associated cancer risk was reduced in the surgery group (hazard ratio [HR], 0.71; P < 0.001), and the female-associated cancer risk was 0.68 (P = 0.004). Breast and endometrial cancer were the most common female-associated cancers in this study, but the HR indicating protection from gastric surgery was significant only for endometrial cancer (HR, 0.56; P = 0.014). Although breast cancer incidence was reduced in the surgery group as well, it did not reach statistical significance. In an accompanying editorial, Peter Argenta suggested that current weight loss approaches are ineffective, given that the women did not lose weight in the nonsurgical group. He also suggested that “bariatric surgery remains, at present, the single best option for rapid, significant, and prolonged weight loss,” although he did express the caveat that the morbidity and cost of surgery are high and must be balanced against benefit.1

Obesity is a chronic, relapsing disease that is poorly understood. Genetics, epigenetics, response to food, and environmental conditions are all causative agents of obesity.2 Given that the current epidemic is starting at younger ages and often occurring in utero, intervention needs to be started earlier. A healthy lifestyle with a healthy weight should be introduced at an early age, and regular exercise should be incorporated into basic health recommendations. Food often satisfies the same pleasure centers as those activated by substance abuse, and food provides pleasurable rewards from eating, which is one reason weight loss and lifestyle changes are so difficult to achieve.2-4 The availability of relatively low-cost fast foods, which are high in carbohydrates, salt, and fat, increases the appeal of these foods and is one of the major drivers of obesity.2 In addition, heritable factors account for 40-80% of the difference in BMI in adult life.5 Body composition, distribution of fat, and visceral fat deposition after periods of overeating share a similar genetic component.5

COMMENTARY

Given that obesity is multifactorial, gastric surgery is a more immediate approach to weight loss than the more difficult approach of lifestyle change. There are a number of obstacles and misconceptions about nutrition and healthy eating in many cultures, as well as an overall decrease in physical activity among both adults and children. Obese parents influence similar patterns of eating and exercise in their children, leading to obese children. Common misconceptions, such as babies are healthier if they are heavier or the sensation of hunger needs immediate satisfaction, perpetuate habits that lead to obesity. Epigenetic factors, such as methylation markers that track with future obesity (ANK3, CDKN2B, CACNA1G, IGDCC4, P4HA3, ZNF423 and MIRLET7BHG) from in utero exposure, increase the probability that their children will become obese.6 Although bariatric surgery is associated with cancer-reducing benefits, it comes with a cost. Many believe that gastric surgery is a panacea for lifestyle change, yet it is associated with significant cost in terms of morbidity and sometimes mortality. We have developed into a society that wants an operation or a pill to fix disease rather than taking personal responsibility for our health. We need to develop comprehensive approaches to addressing this epidemic rather than relying on surgical means, which often fail in the end. Increasing the physical activity of our children and young adults, teaching healthy eating with moderation, and understanding the psychological dependence on food will be necessary to alter this epidemic that is increasing at such a rapid rate. As healthcare providers, it is up to us to challenge our patients to improve their health.

REFERENCES

  1. Argenta PA. Attacking obesity-related diseases at the source — Is bariatric surgery the next wave in cancer prevention? Gynecol Oncol 2017;145:219-220.
  2. Bray GA, Kim KK, Wilding JPH, World Obesity Federation. Obesity: A chronic relapsing progressive disease process. A position statement of the World Obesity Federation. Obes Rev 2017;18:715-723.
  3. Pandit R, Mercer JG, Overduin J, et al. Dietary factors affect food reward and motivation to eat. Obes Facts 2012;5:221-242.
  4. Bray GA. Is sugar addictive? Diabetes 2016;65:1797-1799.
  5. Zillikens MC, Yazdanpanah M, Pardo LM, et al. Sex-specific genetic effects influence variation in body composition. Diabetologia 2008;51:2233-2241.
  6. Lin X, Lim IY, Wu Y, et al; GUSTO study group. Developmental pathways to adiposity begin before birth and are influenced by genotype, prenatal environment and epigenome. BMC Med 2017;15:50. doi: 10.1186/s12916-017-0800-1.