By Louis Kuritzky, MD, Clinical Assistant Professor, University of Florida, Gainesville
Dr. Kuritzky is a retained consultant for Boehringer Ingelheim, Daiichi Sankyo, Forest Pharmaceuticals, Janssen, Lilly, Novo Nordisk, Pfizer, and Sanofi.
Colorectal Cancer Screening Through Stool DNA
Source: Imperiale TF, et al. Multitarget stool DNA testing for colorectal-cancer screening. N Engl J Med 2014;370: 1287-1297.
In their most recent guidance on colon cancer screening (CCS), the American Cancer Society indicated that although a diversity of testing methods are available, since numerous patients are declining to be screened, "the best screening test is the one you can get done." This posture is an effort to reduce the number of unscreened persons, since when discovered early, most colon cancer is curable.
Stool DNA testing is not new. However, head-to-head clinical trials in the past decade have indicated that when compared to colonoscopy, sensitivity for detection of colon cancers and adenomas by older methods of stool DNA testing is lower. Stool DNA CCS is predicated on the fact that mutated and cancerous colonic epithelial cells are consistently excreted daily in the stool, even more commonly than blood is found. DNA panels for CCS, in theory, should be comparable to invasive screening methods, since abnormal DNA should be readily identifiable, and confirmatory colonoscopy and resection should follow. The tepid reception provided to CCS by the public is understandable: Many are put off by the preparation, expense, and inconvenience of colonoscopy. Additionally, in recently published clinical trials of persons undergoing screening colonoscopy, only a small percent actually harbor a cancer or advanced neoplasia (approximately 100 out of 3000 screenees), so it is easy to see why most folks will be correct when they think "it’s probably not me."
Over the last decade, screening panels for stool DNA have been improved. Imperiale et al compared screening by fecal immunochemical testing (FIT) with stool DNA testing, based on a single stool sample for each, followed by colonoscopy in all patients, regardless of screening results.
Sensitivity for colon cancer was superior by DNA stool testing (92.3% vs 73.8%); similarly, sensitivity for high-grade dysplasia favored stool DNA testing (69.2% vs 46.2% sensitivity).
A positive FIT should lead to diagnostic colonoscopy; incorpration of stool DNA testing, when positive, might rightfully provide even further motivation.
Weight-Loss Surgery: Matching Expectations with Realities
Source: Li Z, Heber D. Managing weight loss expectations: The challenge and the opportunity. JAMA 2014;311: 1348-1349.
The degree of success of weight-loss surgery (WLS) for improvement in metabolic derangements such as type 2 diabetes is impressive. Bariatric surgery has even been associated with improved mortality in morbidly obese individuals. Not everyone, however, enjoys the same degree of weight loss, and even though the endpoint of WLS in the minds of clinicians may be improvements in metabolic status and cardiovascular risk, in the minds of patients, the primary endpoint may be more cosmetically oriented. That is, just how much weight am I going to lose?
To better understand the expectations of WLS patients, Li and Heber interviewed patients seeking WLS and asked them (preoperatively) questions to better understand how much weight they expected to lose, the minimum weight loss with which they would not be disappointed, and how much risk they were willing to bear as part of WLS.
On average, patients expected to lose 38% of their weight; the Swedish Obesity Study found that 75% of gastric banding patients lost < 20% of their weight. Even though almost all (84.8%) of the WLS patients understood and accepted that there was a risk of dying from surgery, about one-third of these would no longer be willing to shoulder that risk if the weight loss was only 20%.
WLS has confirmed sustained metabolic and even mortality benefits. However, clinicians must confirm that patients concretely understand these parameters before embarking on such procedures, since some patients may no longer be willing to undertake risk if personally disappointing weight loss results were to occur.