Dietary Calcium Cuts Polyp Risk
Calcium obtained from dietary sources, but not calcium supplements, may protect against the development of colon polyps, Janet A. Tooze, Ph.D., reported in a poster presentation at the annual meeting of the American Society of Preventive Oncology.
In a retrospective study, 598 participants aged 40–69 years completed a food frequency questionnaire in 1992–1994 when they were participating in the Insulin Resistance Arteriosclerosis Study. They later underwent colonoscopy during 2002–2004.
Overall, people in the three highest quartiles of dietary calcium intake were about two to almost three times more likely to be free of colon polyps than were people in the lowest quartile. Supplemental calcium use did not significantly affect the risk for colon polyps. The cutoff for the lowest quartile of calcium intake was about 500 mg per day, said Dr. Tooze of Wake Forest University, Winston-Salem, N.C.
One or more polyps were found in 49% of the participants, including 32% with an adenoma or hyperplastic polyp, 23% with any adenoma, and 6% with an advanced adenoma.
The prevalence of supplemental calcium use was not high—only 15%, according to the researchers. “The source of calcium may be related to the protective effect for polyp development and adenoma development,” the researchers wrote.
Americans Avoid Colon Ca Screening
Aversion to colonoscopy and lack of physician communication are major reasons Americans avoid colon cancer screening, according to a survey of 1,200 people aged 50 to 70 years.
The survey, conducted in February by Harris Interactive, suggests that three out of four eligible Americans are not being screened regularly for this second leading cause of cancer death, a screening rate far lower than rates reported for breast, cervical, and prostate cancers. Only one-third of respondents said they had been screened at least once for colon cancer.
The primary reasons for not being screened included, “don't want to have a colonoscopy” (28%), “doctor did not discuss screening with them” (26%), “did not have any symptoms” (24%), “did not feel they were at risk” (17%), “did not follow through on MD [doctor] recommendations” (9%), “did not know they should be screened” (8%), “did not have time” (5%), and “embarrassed to discuss screening with MD” (4%). Respondents were able to select from more than one category.
Screening rates were highest among those who claimed to be the most knowledgeable about colon cancer. Only 35% of those who considered themselves lacking knowledge about colon cancer had ever been screened, but 79% of respondents who felt they were “knowledgeable” or “very knowledgeable” had been screened.
However, only half of respondents considered themselves knowledgeable about the disease, and far fewer understood the need for, and benefits of, screening.
A personal or family history of the disease was reported by one in five people. Over a third of adults said they were in “excellent” or “very good” health, and three-quarters felt they were doing a good job of managing their own health.
Entecavir vs. Lamivudine for HBV
Two head-to-head phase III trials have shown that the new drug entecavir may be superior to lamivudine for treating chronic hepatitis B.
The two nucleoside drugs were pitted against each other in double-blind trials that involved more than 1,300 patients with HBeAg-positive and HBeAg-negative chronic hepatitis B.
At 48 weeks into the antigen-positive study, histologic improvement was seen in 72% of the entecavir group and 62% of the lamivudine group. Target DNA levels were measured in 21% of patients in the entecavir group and 19% of those taking lamivudine. Significant virologic response occurred in 70% and 46%, respectively. There was no evidence of emerging resistant variants to entecavir, and the frequency of adverse events was similar for the two drugs (N. Engl. J. Med. 2006;354:1001–10).
Of the entecavir patients, 67% had undetectable levels of HBV DNA at 48 weeks. “The efficacy of entecavir appears to result from its potent suppression of HBV replication,” the authors explained.
In the study of HBeAg-negative patients, entecavir produced histologic improvement in 70% of patients, while lamivudine came in at 61%. Among patients not previously treated with a nucleoside analogue, the rates of histologic improvement, serologic response, and normalization of alanine aminotransferase levels were significantly higher at 48 weeks with entecavir than with lamivudine.
Again, the safety profiles of the two drugs were similar, and there was no evidence of viral resistance to entecavir, the investigators reported (N. Engl. J. Med. 2006;354:1011–20).