Discerning individuals at elevated risk for cutaneous melanoma

Dysplastic Nevi are a Risk Factor for Uveal Melanoma

Many studies have characterized the phenotypic features of individuals who are likely to develop cutaneous melanoma. One of the major items included in melanoma risk assessment has been the presence of clinically atypical nevi (dysplastic nevi). This study assessed the number of subjects with dysplastic nevi in groups of patients with uveal melanoma or cutaneous melanoma and in a group of volunteer controls. The SPSS program was used to calculate the odds ratios (hereafter called relative risks; RR) and 95% confidence intervals (C) in melanoma patients and controls. The RR was 4.36 for uveal melanoma (95% Cl 1.84-10.36) and 4.22 for cutaneous melanoma (95% Cl 1.81-9.84). These results suggest that cutaneous dysplastic nevi are a significant risk factor for uveal melanoma.

Family physicians' knowledge of malignant melanoma

BACKGROUND

The incidence and mortality of melanoma have been increasing during the past two decades. Melanoma is relatively easy to detect and, when diagnosed early, is curable.

OBJECTIVE

Our purpose was to assess the baseline knowledge of malignant melanoma among family practitioners and to identify their preferred method of learning new information about the skin.

METHODS

The design was a randomized survey by mailed questionnaire.

RESULTS

More than 50% of physicians stated they lacked confidence in being able to recognize melanoma. Family physicians were well informed on factors affecting prognosis, but knowledge deficits were identified on history, physical examination, and risk factors. The most effective method of learning new information about the skin was hands-on teaching demonstration.

CONCLUSION

Many family physicians are not confident in their ability to recognize melanoma, and knowledge deficits were identified. In addition, some important risk factors were not well recognized. Thus, those at highest risk may not be receiving education on early detection that may help decrease the incidence and mortality of melanoma.

Relationship between skin color and sun exposure history: a statistical classification approach

In this study our aim was to determine the biophysical values of constitutive skin color in Caucasians and to define the correlation between skin color and phototype assessed according to the Fitzpatrick method. Constitutive skin color was measured on the buttock, with a Minolta CR-200 colorimeter, in a population-of 557 consecutive subjects belonging to phototype categories I, II, III and IV. The colorimeter expresses the results in five different color systems. We used the "Yxy" and L*a*b* systems, which are the most widespread in dermatology. Statistical analysis of the data showed that the "Yxy" system is even more discriminant than the L*a*b* system when the Fitzpatrick classification scheme is adopted as the reference and shows a poor ability to correctly classify the intermediate phototypes (II and III). On the contrary the "Yxy" system performs well in distinguishing phototypes I and IV. To establish whether this low discriminating capacity for phototypes II and III is related to a low discriminating capacity of the method suggested by Fitzpatrick or by our procedure, an objective technique (minimal erythemal dose) should be used to evaluate the percentage errors of classification of both the Fitzpatrick method and instrumental measurement of skin color. The results of such a study are extremely important because the evaluation of skin color is objective, simple and has potential applications in dermatology and cosmetology.

Epidemiology of malignant melanoma

Descriptive epidemiology of melanoma indicates increases in both incidence and mortality over the past two to three decades. A moderation in both rates began to emerge in several regions after the 1980s, especially in younger age groups. Recent improvement in survival rates is more likely due to earlier diagnosis than to real improvement in treatment. This suggests the potential effectiveness of secondary prevention. Continued health education efforts to improve awareness about signs and symptoms of melanoma should lead to earlier diagnosis and may increase incidence for a certain period of time. However, reduction in mortality will eventually be achieved owing to thinner melanoma at time of diagnosis. Etiologic studies indicate that the most important environmental risk factor for melanoma is extensive exposure to the sun. Primary prevention efforts should target public education about the risk of sun exposure and the benefit of wearing hats and adequate clothing. Specific prevention and control programs should be implemented among high-risk groups, such as those with light complexions and those sensitive to sunburn. In view of the long latency of melanoma, as much as 10 years, past exposure to the risk factors continues to cause melanoma, and any benefits of preventive efforts do not appear for some time. Although a dramatic decline is not expected in melanoma rates immediately, continuous preventive efforts ultimately should lead to a reduction in incidence and mortality.

Practical applications of cutaneous colorimetry

Dermatologists have long tried to quantify skin color and had few results until the advent of tristimulus colorimetry. With the Minolta colorimeter, quantification of skin color has become a simple matter: skin color can be measured rapidly, noninvasively, and reproducibly. The instrument, which can be used by paramedical staff, provides data that lend themselves for comparison, irrespective of where they are collected. The instrument has enabled definition of the range of physiologic values of skin color, and has revealed marked variations between exposed and nonexposed skin. Constitutional skin color characterizes an individual's phenotype better than facultative skin color and is highly indicative of vulnerability to sunlight. It is therefore a parameter for predicting the immediate and delayed response to light stimulation. On the practical level, colorimetric skin color values can be used to study pigmentation capacity, to program photochemotherapy, and to predict the risk of, and prevent, actinic cancer. Colorimetry can be used to quantify the intensity of erythema of spontaneous and experimental lesions. It has been used to monitor the efficacy of anti-inflammatory treatment of psoriasis and atopic dermatitis. It has also been used in the study of reactions induced by physical and allergic stimuli. Finally, colorimetry is useful in cosmetology for choosing appropriate sunscreens, for studying the effect of depigmentation products, and for determining the delicacy of detergents, and in any other situation that requires the measurement of parameters correlated with skin color that cannot be appreciated by visual observation.

Familial cutaneous melanoma and two-mutational-event modeling

BACKGROUND

According to the Knudson two-mutational-event theory, two mutations at a genetic locus may be required for the development of some cancers. Persons who have inherited a defect in one chromosome and therefore require only one more mutation for cancer development are at a higher risk of manifesting cancer at a younger age than persons without an inherited mutation, who need two acquired "hits." This difference allows one to distinguish familial and sporadic types of the same malignancy by evaluating age of disease onset.

METHODS

To study the role of inheritance in the etiology of familial cutaneous melanoma, characteristics of patients with familial versus nonfamilial melanoma were analyzed according to the Knudson two-mutational-event model.

RESULTS

The familial versus nonfamilial graphs, based on age of diagnosis, did not support this model. However, there was a statistically significant earlier age of diagnosis for patients with familial melanoma. Melanoma thickness was less (i.e., earlier cancer at possibly younger age) for patients with a positive versus a negative family history. Conversely, linear regression, after adjusting for tumor thickness, showed that patients with hereditary melanoma still manifested earlier ages of diagnosis of melanoma compared with sporadic patients.

CONCLUSIONS

Genetic patterns other than the two-step model, additional family-related factors, patient-physician sensitization due to a family history, or a combination of these factors might explain this age difference. More complex multistep modeling of the data may be helpful in better characterizing the genetic patterns of cutaneous melanoma.