The CancerWeb Report, What's New In Cancer: November, 1996
Skin Cancer

• Skin cancer and sun freckles (solar keratoses) - Solar keratoses (SKs), like malignant melanoma (MM) and non-melanoma skin cancer (NMSC), develop in response to sun exposure, specifically to the UV portions of the spectrum. Although SKs are markers for increased risk for all types of skin cancer, epidemiological data regarding the relationship of SKs and NMSC is sparse; any association may reflect only their mutual dependence on sun exposure. NMSC has been much less intensively studied than MM even though it is 8 times more common. Two articles from the Universities of Bristol and Wales in the UK, published in the October, 1996 issue of the British Journal of Cancer, detail the results of a study performed in a random sample of 1,034 subjects aged 60 years and over in South Wales. SKs had an overall prevalence of 23% compared with 2% for NMSC, with a strong trend towards increase with age, and a higher prevalence among men. Over a 1-2-year follow-up, 21% of the SKs regressed, while none became malignant. In the second part of the study, a specific class of NMSC, squamous cell carcinoma (SCC) was examined. Prevalence of SKs and SCC combined was nearly 3.7 times more frequent at 80+ than at 60-64, twice as common in males as in females, over 3 times more common in those with the highest compared with the lowest fifth of sun exposure, and 12 times more frequent in those whose skin never tans and always burns than in those who tan and never burn. After allowing for age (the young have few keratoses and are more likely to use sunscreens), it appeared that use of sunscreens or protective clothing did not provide protection. (Harvey, Br J Cancer 74:1302 and 1308, 1996)

  Editor's Comment: - This topic area is of increasing importance. The incidence of both MM and NMSC has been increasing, and loss of the high-altitude ozone layer is expected to exacerbate this trend, even if the resulting increase in UV is mitigated to some extent by pollution at lower levels. Several interesting facts emerge from the present study. SKs are surprisingly common in South Wales, a region not known for major sun exposure, and these skin lesions had both a high rate of regression and a very low rate of becoming malignant. High regression and low malignant transformation rates also have been described in the much sunnier climate of Australia. This raises questions about the currently accepted wisdom of treating SKs. The lack of effect of sunscreens and protective clothing is troubling. Information gathered in this study did not include SPF values of sunscreens used and there may be other interfering factors at work. Could confidence in protection by screens and clothing lead individuals to increase their sun exposure to a greater extent than they realize, making them underestimate this when recalling it for the study. This subject needs to be explored further, especially since two reports have described an increase in melanoma with increased use of sunscreens.

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• Combined chemotherapy and biotherapy for metastatic melanoma - Melanoma is frequently treated with chemotherapy and/or biological agents used separately, once it has metastasized. A study carried out at the M.D. Anderson Cancer Center in Texas, reported in the October, 1996 issue of Annals of Oncology, described the results of integrating these two types of therapy. Chemotherapy with cisplatin, vinblastine, and DTIC (the CVD regimen) was given with biotherapy that included interleukin-2 and interferon-alpha in an alternating manner at 6-week intervals to 40 patients, and in a sequential manner of CVD followed immediately with biotherapy, or the reverse sequence, to 62 patients. Overall response rates were 33% for alternating (2 complete responses included) and 60% (including 14 complete responses) for the sequential regimen. The sequence CVD to biotherapy gave a higher response rate than the reverse, 69% versus 50%. Median survival was 13 months for sequential treatment versus 9 months for CVD alone. Toxicity was severe, including bone marrow suppression, infections, interleukin-2 effects, and hypotension, but was manageable in all but 15% of patients who required stays in the intensive care unit. (Legha, Ann Oncol 7:827, 1996)