The relationship of malignant melanoma, basal and squamous skin cancers to indoor and outdoor work.

An analysis of occupational incidence data for malignant melanomas and squamous-and basal-self carcinomas of the skin in England and Wales from 1970 to 1975 is reported. The occupational pattern for melanomas of the trunk and limbs differed markedly from the pattern for melanomas of the head, face and neck. Office work was associated with a large excess of melanomas of the trunk and limbs. In contrast, outdoor work was associated with an excess of melanomas of the head, face and neck; and was also associated with an excess of squamous-and basal-cell carcinomas of the skin. This suggests that prolonged occupational exposure to sunlight is an important cause of squamous-and basal-cell carcinomas and of melanomas of the head, face and neck, but not of melanomas on other parts of the body. The high rate of lesions on the trunk and limbs in office workers may reflect their sunbathing or other recreational habits; but it contrasts clearly with other indoor work, where there is a generally low rate of all forms of skin cancer

Breast cancer mortality rates are levelling off or beginning to decline in many western countries: analysis of time trends, age-cohort and age-period models of breast cancer mortality in 20 countries.

Age-standardised mortality rates for breast cancer were examined for 20 countries in Europe, North America, Australia and New Zealand from 1950 to 1992 and age-birth cohort and age-period of death models were fitted to the data. Breast cancer mortality rates generally increased in the earlier decades, but more recently rates have levelled off or begun to decline in most countries. Only in 4 of the 20 countries studied, Belgium, Hungary, Poland and Spain, was there no evidence of a decline or leveling off or mortality in recent birth cohorts or in recent years. In the other countries the decline in mortality appeared to be in part due to birth cohort effects and in part due to period effects. The birth cohort effects were suggestive of a decline in breast cancer rates among women born after about 1920 and were evident in many countries especially Canada, The Netherlands, The United Kingdom and the United States. The decline in mortality in women born after 1920 appeared to be in part related to a reduction in childlessness and a reduction in age at first birth in those generations. As well as the birth cohort effects, there was some evidence of a recent overall decline in mortality rates in several countries, e.g. Austria, FRG, Greece and the UK, and this may be due to an increase in survival resulting from improved management and treatment of women with breast cancer

Malignant melanoma and oral contraceptive use among women in California.

Women who had used oral contraceptives, particularly long-term users, were found to have higher rates of malignant melanoma and of a past history of skin cancer than those who had never used oral contraceptives. This excess was confined to lesions of the lower limb. The association between oral contraceptive use and melanoma was noted in 3 separate sets of data, although it was statistically significant only in one. The possibility that this relationship is indirect because, for example, oral contraceptive users are more likely than never-users to be exposed to sunlight and thus to develop malignant melanoma, cannot be excluded

Risk factors for ovarian cancer: a case-control study.

A hospital-based case-control study of ovarian cancer was conducted in London and Oxford between October 1978 and February 1983. Menstrual characteristics, reproductive and contraceptive history and history of exposure to various environmental factors were compared between 235 women with histologically diagnosed epithelial ovarian cancer and 451 controls. High gravidity, hysterectomy, female sterilisation and oral contraceptive use were associated with a reduced risk of ovarian cancer. Infertility and late age at menopause were associated with an increase in risk. While these factors were related, they were each found to be independently associated with ovarian cancer risk after adjusting for the effect of the other factors

Oral contraceptive use and malignant melanoma in Australia.

In a case control study of 287 women aged 15-24 years with malignant melanoma and 574 matched controls, findings relating to oral contraceptive use and other hormone use are reported. Ever having used oral contraceptives was not associated with an increased risk of melanoma (relative risk for ever use of the pill = 1.0). Women with melanoma were, however, more likely to have taken oral contraceptives for long periods of time in the past, the relative risk associated with oral contraceptive use for a total duration of 5 years or longer which had begun at least 10 years before the melanoma was diagnosed being 1.5 (95% confidence interval 1.03 to 2.14) This elevated risk persisted after controlling for the reported hair and skin colour, frequency of moles on the body, place of birth, and measures of sunlight and fluorescent light exposure. Cases were more likely than controls to have used hormones to regulate their periods, hormonal replacement therapy and be given hormone injections to suppress lactation, the respective relative risks being 1.9, 1.4 and 1.4, but none differed significantly from 1.0. These findings suggest that prolonged oral contraceptive use may, after a lag of 10 years or so, increase the risk of malignant melanoma

Paraplegia and squamous cell carcinoma of the bladder in young women: findings from a case-control study.

A death certificate-based case-control study was conducted on 207 women aged 25-44 who died of bladder cancer in England and Wales in the period 1971-89 and 411 controls matched on sex, year of death and age at death. An odds ratio of 12.0 (95% CI 1.5-99.7) was found for women with a history of paraplegia. Four of the six paraplegic women were reported to have had squamous cell carcinoma of the bladder compared with only 19 of the 201 non-paraplegic women. These findings suggest that squamous cell carcinomas of the bladder, especially in paraplegics, may be the result of chronic urinary tract infection