Dental x-rays and the risk of thyroid cancer: a case-control study.

Unlabelled: The thyroid gland is highly susceptible to radiation carcinogenesis and exposure to high-dose ionising radiation is the only established cause of thyroid cancer. Dental radiography, a common source of low-dose diagnostic radiation exposure in the general population, is often overlooked as a radiation hazard to the gland and may be associated with the risk of thyroid cancer. An increased risk of thyroid cancer has been reported in dentists, dental assistants, and x-ray workers; and exposure to dental x-rays has been associated with an increased risk of meningiomas and salivary tumours.

Socio-economic disparities in access to treatment and their impact on colorectal cancer survival.

Background: Significant socio-economic disparities have been reported in survival from colorectal cancer in a number of countries, which remain largely unexplained. We assessed whether possible differences in access to treatment among socio-economic groups may contribute to those disparities, using a population-based approach.

Methods: We retrospectively studied 71 917 records of colorectal cancer patients, diagnosed between 1997 and 2000, linked to area-level socio-economic information (Townsend index), from three cancer registries in UK.

Some issues in screening for breast and other cancers.

Background: There are some issues in screening for cancer, especially breast cancer, which are worthy of further study.

Methods: We reviewed some approaches to the following issues in breast cancer screening: absolute benefit, overdiagnosis, separation of effects of screening from effects of others on deaths from breast cancer over time and determination of which tumours benefit most from early detection. For separation of screening effects from other effects, we developed a simple analysis of survival by tumour size.

Impact of false-positive mammography on subsequent screening attendance and risk of cancer.

Background: One area of concern within the largely successful UK National Health Service breast screening programme is the relatively high proportion of women showing mammographic abnormalities who undergo further diagnostic tests that prove negative. Previous studies suggest that, in addition to increasing anxiety, such false-positive mammography is associated with increased risk of subsequent interval cancer. In the present article, we quantify this increased risk, investigate whether it extends to cancers detected at rescreening, and determine whether cancers differ between women who have, and have not, experienced false-positive mammography.