Lung-Cancer Screening

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Nov 17, 2005 - for the National Lung Screening Trial. These reports involved clinical trials not designed to evaluate instances of overdiagnosis. Regarding Dr.
The new england journal of medicine

ings suggest that factors beyond GLP-1 stimulate David E. Cummings, M.D. beta cells after Roux-en-Y gastric-bypass surgery. Michael H. Shannon, M.D. For example, decreased ghrelin levels could con- Molly J. Carlson, M.D. tribute, and animal studies implicate an unknown University of Washington factor from the proximal intestine.5 This physi- Seattle, WA 98195 ology, it is important to note, benefits most pa1. Patti ME, McMahon G, Mun EC, et al. Severe hypoglycaemia tients with diabetes who undergo gastric bypass, post-gastric bypass requiring partial pancreatectomy: evidence and overshoot is exceedingly rare. Even if GLP-1 for inappropriate insulin secretion and pancreatic islet hyperoccasionally contributes to beta-cell hypertrophy plasia. Diabetologia (in print). 2. Suzuki S, Ramos EJ, Goncalves CG, Chen C, Meguid MM. in persons with a predisposition — as suggested Changes in GI hormones and their effect on gastric emptying by extremely high levels in two cases of nesidio- and transit times after Roux-en-Y gastric bypass in rat model. blastosis after gastric bypass1 — the risk associ- Surgery 2005;138:283-90. 3. Valverde I, Puente J, Martin-Duce A, et al. Changes in glucaated with pharmacologic stimulation of only the gon-like peptide-1 (GLP-1) secretion after biliopancreatic diverGLP-1 pathway is substantially less than that due sion or vertical banded gastroplasty in obese subjects. Obes Surg to the multifactorial effects of Roux-en-Y gastric- 2005;15:387-97. 4. Clements RH, Gonzalez QH, Long CI, Wittert G, Laws HL. bypass surgery. Beta-cell overgrowth caused by Hormonal changes after Roux-en Y gastric bypass for morbid GLP-1–receptor agonists has never been reported, obesity and the control of type-II diabetes mellitus. Am Surg and if it ever occurs, it should resolve with dis- 2004;70:1-4. 5. Rubino F, Marescaux J. Effect of duodenal-jejunal exclusion continuation of the drug, which is far easier than in a non-obese animal model of type 2 diabetes: a new perspeca reversal of Roux-en-Y gastric-bypass surgery. tive for an old disease. Ann Surg 2004;239:1-11.

Lung-Cancer Screening to the editor: Mulshine and Sullivan (June 30 issue)1 note the high proportion of cancers detected by screening at stage 1. As they acknowledge, however, this proportion cannot be used to indicate the efficacy of screening, which requires a corresponding reduction in the absolute number of advanced lung cancers. Earlier controlled trials, using standard radiography,2,3 failed to achieve this effect. Preliminary analyses of trials that used low-dose computed tomography (CT),4,5 although inconclusive, show no diminution in advanced cancers in the incidence screens as compared with controls. This failure may reflect the proximal endobronchial origin of many cancers (for which CT scanning is relatively insensitive) or the rapid growth of advanced lung cancers. Contrary to the suggestion of the authors, overdiagnosis of clinically insignificant lung cancers remains a concern with screening. Overdiagnosed lung cancers need not differ biologically from lethal cancers: a tumor of 0.5 g with a diameter of 1 cm and a volume-doubling time of 300 days (the mean value for malignant nodules