2 new articles on colorectal cancer screening in NEJM last month.<\/p>\n
1. retrospective review of the nurses’ health study and the health professionals follow-up study (not a randomized controlled trial), of 90K people followed 22 years (see\u00a0<\/b>\u00a0DOI: 10.1056\/NEJMoa1301969). \u00a0results:<\/p>\n
—\u00a0total of 1815 incident cancers and 474 colorectal cancer deaths<\/p>\n
–with any lower endoscopy done, 43% fewer colorectal cancers in those who had a polypectomy for adenoma, 40% fewer in those with negative sigmoidoscopy, and 56% fewer in those with negative colonoscopy. data consistent for men and women.<\/p>\n
–for proximal lesions (prior data suggested less efficacy of screening on proximal lesions), 27% fewer cancers<\/p>\n
–for death from colorectal cancers: 41% fewer with screening sigmoidoscopy and 68% fewer with colonosc<\/p>\n
–reduced mortality from proximal cancers by 53% with colonoscopy and no difference with sigmoidoscopy<\/p>\n
–(not surprisingly) those with cancer diagnosed within 5 years of colonoscopy had more aggressive cancers (CpG island methylator phenotype — CIMP — and microsatellite instability)<\/p>\n
–benefit of colonoscopy extended 15 years for both proximal and distal tumors. \u00a0the numbers of individuals are significantly smaller in the group getting screening in the 10-15 year range (and it appears that they do even better), though the group with screening >15 years was worse (but still 31% lower than the controls) — so these authors suggest sticking with 10 years as the appropriate screening interval in those with normal initial colonoscopy.<\/p>\n
–also, aspirin had no benefit beyond colonoscopy alone<\/p>\n
so, this study did show significant benefit of colonoscopy for proximal tumors (there were articles a couple of years ago suggesting that we only do sigmoidoscopy because it is safer\/cheaper\/easier on the patient and the data on efficacy for proximal tumors was pretty questionable) and a clear\/persistent benefit to screening, even if not repeated for more than 15 years<\/p>\n
2. 30 year followup of the minnesota colon cancer control study (see\u00a0DOI: 10.1056\/NEJMoa1300720). 47K people studied, randomized to usual care vs annual or biennial fecal occult blood testing (this was a pretty profound study at the time, though 82.5% of the FOBT slides were rehydrated, which creates 4 times as many false positive results — 9.8% per screening in those with rehydrated slides vs 2.4% in those without rehydration — and then leading to 38%\u00a0of those in the annual and 28% in those in the biennial groups getting colonoscopy (12,246 colonoscopies!!!). in some ways, this perhaps ended up being more of a colonoscopy study, since so many were done…..). the initial study results reported in 1993 (see\u00a0Mandel J, NEJM 1993; 328: 1365-71) found a 33% decrease in colorectal cancer mortality, leading to the generalized recommendations to screen for colon ca.\u00a0results of the longterm followup:<\/p>\n
–732 deaths from colorectal cancer (by death certificates)<\/p>\n
–screening led to 32% decreased colorectal cancer mortality in the annual screening group and 22% in the biennial group through the 30 years of followup. no diff in all-cause mortality. men benefited more than women in the biennial screening group<\/p>\n
–no diff in total mortality<\/p>\n
so, pretty clear that colon cancer screening is important, has durable benefit over the longterm, and (i think) both studies ultimately reinforce colonoscopy as the most effective tool.<\/p>\n
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geoff<\/p>\n","protected":false},"excerpt":{"rendered":"
Colon cancer screening effective, colonoscopy most effective […]<\/p>\n