Cutaneous malignant melanoma

Case report of primary rectal melanoma and review of the etiology of melanoma

BACKGROUND

Primary rectal melanoma is a very rare and aggressive malignancy. It is defined as melanoma arising in the rectal mucosa, more than 4 cm from the anal verge.

OBJECTIVE

A case of primary rectal melanoma is reported, and the theories of the etiology of melanoma are reviewed.

METHODS AND RESULTS

This article reports a case of a 75-year-old woman who presented with lower gastrointestinal bleeding and abdominal discomfort. A polyp was removed from the low-lying rectum during colonoscopy. After immunohistochemical staining and microscopic examination, it was diagnosed as melanoma.

CONCLUSION

In light of primary melanoma in sun-shielded regions such as the rectum, theories of causation other than sun exposure merit consideration. Factors such as genetics, immunosuppression, and virus infections, as well as ultraviolet radiation, may play a role in the etiology of melanoma.

Incidence of cancer among female flight attendants: a meta-analysis

BACKGROUND

Airline flight personnel work in a unique environment with exposure to known or suspected carcinogens and mutagens including ionizing cosmic radiation. A meta-analysis was conducted to study whether the occupational exposure of female flight attendants (FA) increased their relative risk of cancer incidence.

METHODS

A bibliographical computer search from 1966 to 2005 of cancer incidence cohort studies of female FA was performed. Combined relative risks (RRc) in cancer incidence were calculated by means of meta-analysis.

RESULTS

RRc and 95% confidence interval (CI) for malignant melanoma and breast cancer in female FA were 2.13 (95% CI: 1.58-2.88) and 1.41 (1.22-1.62) (p < 0.0001). Excess risk was not significant for all-site cancer with RRc of 1.10 (0.99-1.21).

CONCLUSIONS

The meta-analysis confirmed the significantly increased risks for malignant melanoma and breast cancer in female FA. Increased exposure to cosmic radiation during flight has been suggested as a potential occupational risk factor. Ultraviolet radiation exposure on board seems an unlikely occupational risk, but nonoccupational leisure time sun exposure is a possible risk factor. The etiology of the observed increase in incidence of some cancers remains controversial because assessment of possible confounders, especially nonoccupational exposure factors, has thus far been limited.

Skin cancer identification using multifrequency electrical impedance--a potential screening tool

Electrical bio-impedance can be used to assess skin cancers and other cutaneous lesions. The aim of this study was to distinguish skin cancer from benign nevi using multifrequency impedance spectra. Electrical impedance spectra of about 100 skin cancers and 511 benign nevi were measured. Impedance of reference skin was measured ipsi-laterally to the lesions. The impedance relation between lesion and reference skin was used to distinguish the cancers from the nevi. It was found that it is possible to separate malignant melanoma from benign nevi with 75% specificity at 100% sensitivity, and to distinguish nonmelanoma skin cancer from benign nevi with 87% specificity at 100% sensitivity. The power of skin cancer detection using electrical impedance is as good as, or better than, conventional visual screening made by general practitioners.

Diet and Melanoma in a Case-Control Study

Background: Malignant melanoma has been one of the most rapidly increasing cancers within the United States with few modifiable risk factors. This study investigates risk related to dietary factors, which are potentially modifiable. Methods: Newly diagnosed patients with melanoma (n = 502) were recruited from pigment lesion clinics and controls (n = 565) were recruited from outpatient clinics. To investigate the relationship between melanoma and dietary factors in this case-control study, study subjects were requested to complete a food frequency questionnaire, which assessed diet over the previous year. Using logistic regression, odds ratios (ORs) for melanoma were computed for nutrient and alcohol intake. Results: Persons in high versus low quintiles of energy-adjusted vitamin D, α-carotene, β-carotene, cryptoxanthin, lutein, and lycopene had significantly reduced risk for melanoma (ORs ≤ 0.67), which remained after adjustment for presence of dysplastic nevi, education, and skin response to repeated sun exposure. Addition of micronutrients from supplements did not add an additional reduction in risk. High alcohol consumption was associated with an increased risk for melanoma, which remained after adjustment for confounders [OR (95% confidence interval) in highest versus lowest quintiles, 1.65 (1.09-2.49)]. Conclusions: Diets consisting of foods rich in vitamin D and carotenoids and low in alcohol may be associated with a reduction in risk for melanoma. These analyses should be repeated in large, prospective studies.