Diagnostic radiation procedures and risk of prostate cancer.

Exposure to ionising radiation is an established risk factor for many cancers. We conducted a case-control study to investigate whether exposure to low dose ionisation radiation from diagnostic x-ray procedures could be established as a risk factor for prostate cancer. In all 431 young-onset prostate cancer cases and 409 controls frequency matched by age were included. Exposures to barium meal, barium enema, hip x-rays, leg x-rays and intravenous pyelogram (IVP) were considered. Exposures to barium enema (adjusted odds ratio (OR) 2.06, 95% confidence interval (CI) 1.01-4.20) and hip x-rays (adjusted OR 2.23, 95% CI 1.42-3.49) at least 5 years before diagnosis were significantly associated with increased prostate cancer. For those with a family history of cancer, exposures to hip x-rays dating 10 or 20 years before diagnosis were associated with a significantly increased risk of prostate cancer: adjusted OR 5.01, 95% CI 1.64-15.31 and adjusted OR 14.23, 95% CI 1.83-110.74, respectively. Our findings show that exposure of the prostate gland to diagnostic radiological procedures may be associated with increased cancer risk. This effect seems to be modified by a positive family history of cancer suggesting that genetic factors may play a role in this risk association.

Delivery of cancer genetics services: The Royal Marsden telephone clinic model.

We have conducted a telelink telephone-led cancer genetic counselling model at The Royal Marsden NHS Foundation Trust. The study commenced in March 2004 and evaluation of the clinic was conducted over 17 months from March 2005 to the end of July 2006. A total of 612 patients had telephone consultations during this time, 228 of whom were referred from primary care with a median of 30 patients counselled per month (range of 19-63, depending on staff availability with average of two staff per clinic). Waiting times were measured for General Practitioner referrals and all 228 were counselled within the national target-stipulated 13 weeks (median 6 weeks, range 1-12). An additional 132 patients who were sent appointment letters after receipt of their family history questionnaires did not attend their appointments (18% of all potential referrals) and required recontacting by letter. After telephone counselling, 42% of patients were able to be discharged from the telephone clinic without a subsequent face-to-face appointment, thereby saving resources. The telephone clinic also had a short set-up time with flexibility on timing and day of administration, which would be an advantage in centres where outreach clinic facilities are scarce. The telelink telephone counselling model is highly efficient in triaging high risk individuals for face-to-face counselling as per the Kenilworth model, in effecting concentration of resources and in providing a flexible individual-centred approach to cancer genetic counselling delivery.

Association between the GCG polymorphism of the selenium dependent GPX1 gene and the risk of young onset prostate cancer.

Epidemiological studies have suggested an association between low selenium levels and the development of prostate cancer. Human cellular glutathione peroxidase I (hGPX1) is a selenium-dependent enzyme that protects against oxidative damage and its peroxidase activity is a plausible mechanism for cancer prevention by selenium. The GPX1 gene has a GCG repeat polymorphism in exon 1, coding for a polyalanine tract of five to seven alanine residues. To test if the GPX1 GCG repeat polymorphism associates with the risk of young-onset prostate cancer we conducted a case-control study. The GPX1Ala genotypes were determined for 267 prostate cancer cases and 260 control individuals using polymerase chain reaction (PCR) amplification with fluorescently labelled primers and an ABI 377 automated genotyper. Associations between specific genotypes and the risk of prostate cancer were examined by logistic regression. We found no significant association between the GPX1 genotypes and prostate cancer. There was however an increased frequency of the GPX1Ala6/Ala6 genotype in the prostate cancer cases compared to controls (OR: 1.67; 95% CI: 0.97-2.87). The result of this study suggests that the GPX1 genotype is unlikely to be associated with the risk of developing prostate cancer.