Obesity, Bariatric Surgery, and Cancer
Surgeons with our national Society, the American Society for Metabolic and Bariatric Surgery (ASMBS) have recently published a summary of the known medical literature about the relationship of obesity and cancer, and the likely benefits of bariatric surgery in cancer reduction. They report surprising increases in cancer rates caused by the Obesity Disease, and in particular the fact that cancer tends to show up at a younger age in those with Obesity. There is some good news in the report: the researchers outline multiple studies that have shown that weight reduction (especially the dramatic weight reduction of bariatric surgery) can dramatically reduce the risk of cancer occurrence and the risk of cancer recurrence.
Obesity Leads to Increased Risk of Cancer
The first key piece of knowledge is that the Obesity Disease leads to significant increases in the risk of several types of cancer. The cancers with increased risk include cancer of the breast, endometrium, cervix, prostate, thyroid, stomach, liver, kidney, pancreas, gallbladder and some ovarian sub-types. The Obesity Disease also leads to higher rates of esophageal adenocarcinoma, colon and rectal cancer, multiple myeloma, non-Hodgkin’s lymphoma, and melanoma. The data indicates that 9.5% of new cancers in women are attributable to the increased risk caused by obesity, and that number is 3.5% for new cancers in men. It was separately estimated that obesity has recently contributed to 20% of all cancer deaths in women and to 14% of cancer deaths in men.
Patients With Obesity May Get Cancer at Younger Ages
The researchers identified a new concern, which is that cancers typically seen in older individuals are now showing up in obese individuals who are still less than 50 years old. In other words, the Obesity Disease seems to accelerate the onset of certain cancers, which include breast, colorectal, kidney, endometrial, thyroid, liver, gastric, meningioma (brain cancer), ovarian, and esophageal adenocarcinoma.
The researchers believe that obesity promotes the development of cancer through multiple synergistic mechanisms, including proinflammatory cytokines, elevated reactive oxygen species, abnormally elevated growth factors, increased conversion of androgen hormones to estrogens, reduced growth-controlling adipokines, distortion of the gut microbiota with increase in tumor-promoting species, and increased reflux leading to greater likelihood of esophageal cancer.
Cancer Mortality Increased in Patients With Obesity
A study from Canada, where the average wait time from referral for bariatric surgery to the actual operation is reported to be 5.2 years, the most common cause of death in patients awaiting bariatric surgery was cancer. The mortality for patients on the waiting list was 1.57%, which was three times higher than for the overall Canadian population in the same time-frame.
Cancer Screening Limitations
In addition to the biologic factors noted above, the researchers point out that screening for cancer can be more difficult in those with the Obesity Disease. One good example of this is the difficulty of mammography in women with the Obesity Disease, along with the difficulty of conducting thorough pelvic exams. Physicians who care for those with the Obesity Disease are called on to be particularly vigilant about cancer screening.
Bariatric Surgery Reduces Cancer Risk
As we would hope, it has been shown that weight loss reduces cancer rates toward the expected rates for the population as a whole. It has also been shown in multiple studies that bariatric surgery is particularly effective in risk reduction as it leads to massive weight reduction. Cancers that have specifically been shown to benefit from weight loss and bariatric surgery include breast, endometrial, renal, prostate, and colorectal cancer.
More information is developing in this area, and there are a number of clinical trials underway that hope to confirm and to quantify the benefits of intentional weight loss. Most of these trials are in breast cancer patients, and they include the ENERGY trial, the BWEL trial, the SUCCESS-C trial, and the DIANA-5 trial. All these studies pursue weight loss through lifestyle intervention, which is unfortunately not as effective as bariatric surgery.
Bariatric Surgery Safety in Cancer Patients
Since about 38.4% of individuals in the U.S. will be diagnosed with cancer at some point in their life, many who seek bariatric surgery have already undergone cancer treatment. Oncology physicians are generally supportive of bariatric surgery interventions in patients who are otherwise good candidates, once cancer treatment reaches an appropriate stage.
There are even some types of cancer, such as renal cell cancer, where bariatric surgery may be appropriate as part of the cancer treatment. This is a slow-growing cancer, which can sometimes be removed while leaving most of the kidney intact. Urology surgeons may find the delicate “partial” resection to be impractical in the context of serious obesity, but much safer and more practical after 50+ pounds of weight loss.
For More Information
For more information on obesity, bariatric surgery, and cancer and how weight loss can help you, make an appointment at an experienced weight loss program with doctors who are trained in Obesity Medicine and Bariatric Surgery, such as Sage Bariatric Institute in San Antonio. Addressing obesity affects so much more than how you look and feel. Call Sage Bariatric at (210) 651-0303 or go to the website at SageBariatric.com.