Biomedical subjects

Andrew Shenton

Publications and source records attributed to Andrew Shenton.

5 recordsLinked to original sources

PubMed2006

BRCA1, BRCA2 and TP53 mutations in very early-onset breast cancer with associated risks to relatives.

Pathological mutations in BRCA1, BRCA2 and TP53 are associated with an increased risk of breast cancer. This study evaluated mutation frequency of these genes in early-onset breast cancer patients, and correlated this with family history and determined relative risks to family members. Patients with breast adenocarcinoma diagnosed 30 years were ascertained between 1980 and 1997. Family history was established and mutation screening of BRCA1, BRCA2 and TP53 genes was performed. Estimates of penetrance and relative risk were undertaken. DNA was obtained from 100/139 women. 17/36 familial cases had a BRCA1, BRCA2 or TP53 mutation. Of 64 non-familial cases, one BRCA2, two BRCA1 and two TP53 mutations were detected. Penetrance estimates (by age 70) for breast cancer were 84% for BRCA1 mutations and 91% for BRCA2 mutations and for ovarian cancer, 60% and 26%, respectively. Relative risks associated with mutations were consistent with previous studies. BRCA1 and BRCA2 mutations in patients with breast cancer 30 years are predicted strongly by family history. The majority of families with ovarian cancer were due to mutations in BRCA1/2 whereas these mutations only accounted for 30-50% of the excess breast cancers.

Adenocarcinoma↗

PubMed2006

Parity and breast cancer risk among BRCA1 and BRCA2 mutation carriers.

INTRODUCTION: Increasing parity and age at first full-term pregnancy are established risk factors for breast cancer in the general population. However, their effects among BRCA1 and BRCA2 mutation carriers is still under debate. We used retrospective data on BRCA1 and BRCA2 mutation carriers from the UK to assess the effects of parity-related variables on breast cancer risk. METHODS: The data set included 457 mutation carriers who developed breast cancer (cases) and 332 healthy mutation carriers (controls), ascertained through families seen in genetic clinics. Hazard ratios were estimated by using a weighted cohort approach. RESULTS: Parous BRCA1 and BRCA2 mutation carriers were at a significantly lower risk of developing breast cancer (hazard ratio 0.54, 95% confidence interval 0.37 to 0.81; p = 0.002). The protective effect was observed only among carriers who were older than 40 years. Increasing age at first live birth was associated with an increased breast cancer risk among BRCA2 mutation carriers (p trend = 0.002) but not BRCA1 carriers. However, the analysis by age at first live birth was based on small numbers. CONCLUSION: The results suggest that the relative risks of breast cancer associated with parity among BRCA1 and BRCA2 mutation carriers may be similar to those in the general population and that reproductive history may be used to improve risk prediction in carriers.

Adult↗

PubMed2005

Screening for familial ovarian cancer: failure of current protocols to detect ovarian cancer at an early stage according to the international Federation of gynecology and obstetrics system.

PURPOSE: To assess the effectiveness of annual ovarian cancer screening (transvaginal ultrasound and serum CA-125 estimation) in detecting presymptomatic ovarian cancer in women at increased genetic risk. PATIENTS AND METHODS: A cohort of 1,110 women at increased risk of ovarian cancer were screened between January 1991 and March 2004; 553 were moderate-risk individuals (4% to 10% lifetime risk) and 557 were high-risk individuals (> 10% lifetime risk). Outcome measurements include the number and stage of screen-detected cancers, the number and stage of cancers not detected at screening, the number of equivocal screening results requiring recall/repetition, and the number of women undergoing surgery for benign disease. RESULTS: Thirteen epithelial ovarian malignancies (12 invasive and one borderline), developed in the cohort. Ten tumors were detected at screening: three International Federation of Gynecology and Obstetrics (FIGO) stage I (including borderline), two stage II, four stage III, and one stage IV. Of the three cancers not detected by screening, two were stage III and one was stage IV; 29 women underwent diagnostic surgery but were found not to have ovarian cancer. CONCLUSION: Annual surveillance by transvaginal ultrasound scanning and serum CA-125 measurement in women at increased familial risk of ovarian cancer is ineffective in detecting tumors at a sufficiently early stage to influence prognosis. With a positive predictive value of 17% and a sensitivity of less than 50%, the performance of ultrasound does not satisfy the WHO screening standards. In addition, the combined protocol has a particularly high false-positive rate in premenopausal women, leading to unnecessary surgical intervention.

Adult↗

PubMed2004

BRCA1/2 predictive testing: a study of uptake in two centres.

Differences in reported uptake of genetic testing for mutations in BRCA1 and BRCA2 can largely be accounted for by different methodologies and by studying research vs nonresearch families. In our joint study of 75 nonresearch families from two UK centres in which at least 3 years had elapsed since the initial proband had been informed of the availability of testing, only 45 and 34% of eligible individuals from Manchester and London, respectively, had come forward for counselling. Final uptake rates using a non-proactive approach were 53 and 29% for women and 11-12% for men, but the figure among those attending clinic was 73 and 62%, respectively. Unlike previous studies, we did not find that uptake had stabilised after a year with 25% of those being tested more than 2 years after the family was informed, and several delaying a considerable time between genetics appointments. We believe that the particularly low uptake even of counselling in men may need to be addressed by improving family communication or providing information sheets for family members to disseminate.

Female↗

PubMed2003

Bayesian evaluation of breast cancer screening using data from two studies.

The mean sojourn time (the duration of the period during which a cancer is symptom free but potentially detectable by screening) and the screening sensitivity (the probability that a screen applied to a cancer in the preclinical screen detectable period will result in a positive diagnosis) are two important features of a cancer screening programme. Little data from any single study are available on the potential effectiveness of mammographic screening for breast cancer in women with a family history of the disease, despite this being an important public health issue. We develop a method of estimation, from two separate studies, of the two parameters, assuming that transition from no disease to preclinical screen detectable disease, and from preclinical disease to clinical disease, are Poisson processes. Estimation is performed by a Markov chain Monte Carlo algorithm. The method is applied to the synthesis of two studies of mammographic screening in women with a family history of breast cancer, one in Manchester and one in Kopparberg, Sweden.

Adult↗