DNA content of rectal scrapings from individuals at low and high risk for the development of colorectal cancer: a feasibility study

Article Abstract:

Early detection is an extremely important factor contributing to the reduction of cancer deaths. Towards this end, attempts were made to devise a screening procedure for colorectal cancer, which would be analogous to the Pap smear used in the early detection of cervical cancer. Scrapings from rectal mucosa were taken from high- and low-risk patients; the high-risk group consisted of 31 patients with colorectal carcinoma and 66 patients with sporadic adenoma. Fifty-three control subjects had no family history of colorectal cancer. Flow cytometry, in which the DNA content of stained cells is automatically quantified, was used to determine if there were any cell cycle characteristics which might distinguish between the high- and low-risk populations. The DNA index, an estimation of the amount of DNA compared with a normal diploid cell, was calculated, as were the percentages of cells in the G1, S, G2, and M phases of the cell cycle. (In practice, the G2 and M phases are lumped together.) The GMS index, which is the ratio of cells in the G2 and M phases to those in the S phase was also calculated. Five, or 15.6 percent, of 32 scrapings with colorectal carcinoma had DNA profiles indicating an abnormal aneuploid chromosome complement. Only 3.8 percent of the controls had aneuploid profiles. Patients with adenomas and a family history of adenoma had 5.9 percent rate of aneuploidy, while patients with adenoma but without a family history had a 10.2 percent rate. When the GMS index was considered, 15.4 percent of the colorectal carcinoma patients had values outside normal limits, in contrast with 12.5 percent for adenoma patients with family history, 4.9 percent for adenoma patients without family history, and 5.9 percent for low-risk control patients. The authors believe their results indicate that there is promise for developing a mass screening program for colorectal cancer risk. (Consumer Summary produced by Reliance Medical Information, Inc.)

Usage, Colorectal cancer, Flow cytometry, Ploidy

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Factors delaying the diagnosis of oral and oropharyngeal carcinomas

Article Abstract:

Delayed diagnosis of oral and oropharyngeal (mouth and throat) cancer occurs in 67 to 77 percent of patients. The late diagnosis of these tumors should not occur because distinct symptoms are present in the early stages of the disease, including slow growth on the mucosal membranes, the front of the tongue, floor of the mouth, palate and gingiva (gum surrounding the teeth). The failure to diagnose this cancer in its early stages contributes to the continued poor prognosis for patient with oral and oropharyngeal cancer. A study was conducted to identify the reasons for delayed diagnosis on the part of both professionals (dentists in this study) and dental patients. The study found that patients did not recognize early signs these cancers: none of the patients seemed alarmed by the early warning signs and did not associate them with cancer. Another factor delaying the recognition of a tumor may be the long interval between the asymptomatic and symptomatic stages of development. These tumors grow slowly and may not arouse suspicion until they become painful, infected, or encroach on other structures in the mouth. The delayed diagnostic response by dental professionals remains frustrating. Probable causes for the failure of dental professionals to act quickly are: failure to do a thorough examination, misinterpretation of signs and symptoms, low suspicion, lack of experience or unfamiliarity with oral and oropharyngeal cancer. The dental profession must develop new strategies to attract and encourage the patients to undergo periodic oral examination as a preventive diagnostic measure against oral cancer and focus on high risk populations such as persons over 50 years of age with a history of tobacco use.

Mouth cancer, Medical examination, Periodic health examinations, Throat cancer, Pharyngeal cancer

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Association between smoking and leukemia in two American Cancer Society prospective studies

Article Abstract:

Tobacco smoke contains the radioactive compounds urethane, nitrosamines, and benzene, all of which have been shown to cause cancer in laboratory animals. While the role of cigarette smoking in lung cancer has been widely publicized, the relationship between smoking and leukemia is still a matter for scientific research. Data gathered from two massive prospective studies, involving 2,200,000 individuals over more than 30 years, were analyzed for correlations between smoking and leukemia. The risk of lymphatic leukemia was found to be unrelated to smoking. However, the risk of myeloid leukemia was found to be higher among men who smoke, but not among smoking women. Such a sex difference has been observed in experimental animals. In fact, a study of the development of leukemia in mice indicated that not only does cigarette smoke actively increase the risk of leukemia among the male mice, but the risk is actually decreased by cigarette smoke among the female mice. That is, the combination of cigarette smoke and being female actually protects against leukemia, at least in the C57DL strain of mice. Further epidemiologic research will be necessary to determine if a similar phenomenon might be at work in humans. (Consumer Summary produced by Reliance Medical Information, Inc.)

Demographic aspects, Smoking, Leukemia, Cigarettes

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