NEJM Teaching Topics

Flex Sigmoidoscopy and Colorectal Cancer

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Teaching Topic
Flexible Sigmoidoscopy and Colorectal Cancer
Original Article

R.E. Schoen and Others

CME Exam  Comments

Colorectal cancer is the second leading cause of cancer-related deaths in the United States. Colorectal-cancer mortality and incidence are reduced with screening by means of fecal occult-blood testing. Endoscopic screening with flexible sigmoidoscopy or colonoscopy is more sensitive than fecal testing for the detection of adenomatous polyps, the precursor lesions of colorectal cancer.

Clinical Pearls
Clinical Pearl  What were the results of this randomized trial comparing flexible sigmoidoscopy to usual care for screening of colorectal cancer?

In this randomized study, flexible sigmoidoscopy, as compared with usual care, was associated with a 26% reduction in overall colorectal-cancer mortality and a 21% reduction in the incidence of colorectal cancer. Mortality related to distal colorectal cancer was reduced by 50%, and the incidence was reduced by 29%. A significant 14% reduction in the incidence of proximal colorectal cancer was observed, but there was no significant reduction in mortality related to proximal cancer.

Clinical Pearl  According to the authors, what were the numbers needed to invite for screening via flexible sigmoidoscopy to prevent one diagnosis of colorectal cancer and one colorectal-cancer death?

In this study, the number needed to invite for screening in order to prevent 1 case of colorectal cancer was 282 (95% CI, 210 to 427). The number needed to invite for screening to prevent 1 colorectal-cancer death was 871 (95% CI, 567 to 1874).

Morning Report Questions
Q. How did study participants differ from the usual-care group?

A. Participants in the intervention group were offered two screenings with flexible sigmoidoscopy, 3 to 5 years apart. Median follow up was 11.9 years. In the intervention group, 86.6% of participants (67,071) underwent at least one flexible sigmoidoscopic screening, and 50.9% (39,440) underwent two screenings. The estimated rate of endoscopy in the usual-care group during the screening phase was 25.8% (95% CI, 23.6 to 28.0) for flexible sigmoidoscopy, 34.4% (95% CI, 32.0 to 36.8) for colonoscopy, and 46.5% (95% CI, 43.9 to 49.1) for either flexible sigmoidoscopy or colonoscopy.

Q. How did screening-detected cancers differ from those diagnosed among participants who were never screened in terms of location and stage?

A. Screening-detected cancers accounted for 24.1% of colorectal cancers (244 of 1012) in the intervention group. Among participants with screening-detected cancers, 82.8% of the cancers were distal, whereas among participants who were never screened, 52.8% were distal, and among participants with cancers not detected by screening, 31.6% were distal (P<0.001). Participants with screening-detected cancers were more likely to have early-stage cancer (stage I or II) than participants who were never screened or those whose tumors were not detected by screening (75.4% vs. 50.9% and 50.7%, respectively; P<0.001).

Table 3. Colorectal-Cancer Incidence and Stage According to Means of Detection.

NEJM Resident eBulletin – Elevated PSA

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Teaching Topic

Elevated PSA

Case Records of the Massachusetts General Hospital

Case 9-2012: A 67-Year-Old Man with a Persistently Elevated PSA Level

D.S. Kaufman and Others

CME Exam

At least 30% of clinically important prostate cancers may be missed during transrectal ultrasound-guided biopsy, and the results are not improved if more than 12 cores are taken (so-called “saturation biopsies”).

Clinical Pearls

Clinical Pearl  What is a Gleason score?

The Gleason score is the sum of the two most common histologic grades in a prostate-gland tumor, each of which is rated on a scale of 1 to 5, with 5 being the most cytologically aggressive. It correlates with prognosis. A higher score is more likely to be seen with disease that is not confined to the prostate, and is also correlated with poorer response to treatment of localized disease.

Clinical Pearl  What are the criteria for active surveillance in prostate cancer?

The authors report that criteria for active surveillance for prostate cancer include a PSA level less than 10 ng per milliliter. While the decision to carry out active surveillance is one that must be individualized, in general, in addition to having a relatively low PSA, patients with early clinical disease stage and a Gleason score indicating well or moderately differentiated tumor may be considered for active surveillance.

Morning Report Questions

Q. What is transperineal template-guided mapping biopsy (TTMB) of the prostate?

A. Traditional transrectal ultrasound-guided needle biopsy of the prostate allows excellent and convenient sampling of the posterior aspect of the prostate gland, where prostate cancers most commonly originate. On occasion, however, the cancer may arise either centrally or anteriorly and may be beyond the reach of a biopsy needle inserted through the rectum. However, the anterior gland can be reached through a perineal approach, a technique that is used to insert radioactive seeds into the prostate gland for the purpose of treatment (brachytherapy). Precision is needed to ensure that the needles are placed correctly. To achieve this, transrectal ultrasonography is used to visualize the needles, and the needles themselves are passed through holes in a template (grid) that is secured against the perineum. The perforations ensure that the needles are inserted in parallel and with a known relationship to one another. The “repurposing” of this brachytherapy technique for prostate biopsy is known as TTMB, or “grid” biopsy, and the template may be used to insert biopsy needles precisely to any location in the prostate gland.

Figure 3. Transperineal Template-Guided Mapping Biopsy of the Prostate.

Q. What are the indications for consideration of TTMB?

A. A PSA level higher than expected for the size of the gland should prompt consideration of TTMB for better sampling of the prostate. Biopsies performed with the use of templates are important for carefully selected patients in whom there is an unexplained discordance between PSA readings and findings on examination of biopsy specimens obtained via transrectal approach. One quarter of patients who undergo TTMB after at least one negative specimen obtained by transrectal ultrasound-guided biopsy will have positive results on TTMB. Up to half of these patients have cancers with a Gleason score of 7 or higher. In patients with two or more negative specimens from transrectal ultrasound-guided biopsies, the most common finding in specimens obtained by TTMB was cancer in the anterior lobes. The morbidity associated with TTMB is greater than that associated with transrectal ultrasound-guided biopsies; there is a higher incidence of acute urinary obstruction. Overall, the costs associated with TTMB (e.g., the costs of general anesthesia, the operating room, and the processing of a large number of tissue cores) render it far more expensive than transrectal ultrasound-guided biopsies.

NEJM Resident e-Bulletin Teaching Topics 11.03.11

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The next time you get asked by a sales professional why you rated her client for ulcerative colitis pull out this cheat sheet for talking points.

Q. What is the risk of cancer in patients with ulcerative colitis?

A. On the basis of data from referral centers, the cumulative risk of colorectal cancer among patients with chronic ulcerative colitis may reach 20 to 30% at 30 years, but the incidence rate is much lower in population-based series (approximately 2%). Risk factors for cancer include a long duration of disease, regardless of clinical activity; extensive involvement; a young age at onset; severe inflammation; the presence of primary sclerosing cholangitis; and a family history of colorectal cancer.