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Peter Ainsworth

Publications and source records attributed to Peter Ainsworth.

13 recordsLinked to original sources
PubMed2006

Salpingo-oophorectomy and the risk of ovarian, fallopian tube, and peritoneal cancers in women with a BRCA1 or BRCA2 Mutation.

CONTEXT: Women with BRCA1 or BRCA2 mutation are often advised to undergo preventive oophorectomy. The effectiveness of this intervention has not been prospectively evaluated in a large cohort. OBJECTIVES: To estimate the incidence of ovarian, fallopian tube, and primary peritoneal cancer in women who carry a deleterious mutation in BRCA1 or BRCA2. To estimate the reduction in risk of these cancers associated with a bilateral prophylactic salpingo-oophorectomy. DESIGN, SETTING, AND PARTICIPANTS: Women known to carry a BRCA1 or BRCA2 mutation were identified from an international registry between 1992 and 2003. A total of 1828 carriers at 1 of 32 centers in Canada, the United States, Europe, and Israel completed questionnaires at baseline and follow-up. Participants were observed from the date of study entry until: diagnosis of ovarian, fallopian tube, or peritoneal cancer; death; or the date of the most recent follow-up. INTERVENTION: Participants were divided into women who had undergone bilateral prophylactic oophorectomy and those who had not. MAIN OUTCOME MEASURE: The incidence of ovarian, peritoneal, and fallopian tube cancer was determined by survival analysis. The risk reduction associated with prophylactic salpingo-oophorectomy was evaluated by a time-dependent survival analysis, adjusting for covariates. RESULTS: After a mean follow-up of 3.5 years, 50 incident ovarian, fallopian tube, and peritoneal cancer cases were reported in the cohort. Of the 1828 women, 555 (30%) underwent a bilateral prophylactic salpingo-oophorectomy prior to study entry, 490 (27%) underwent the procedure after entering the study, and 783 (43%) did not undergo the procedure. There were 32 incident cancers diagnosed in women with intact ovaries (1015/100,000 per year). Eleven cancer cases were identified at the time of prophylactic oophorectomy and 7 were diagnosed following prophylactic oophorectomy (217/100,000 per year). The estimated cumulative incidence of peritoneal cancer is 4.3% at 20 years after oophorectomy. The overall (adjusted) reduction in cancer risk associated with bilateral oophorectomy is 80% (multivariate hazard ratio = 0.20; 95% confidence interval, 0.07-0.58; P = .003). CONCLUSION: Oophorectomy is associated with reduced risk of ovarian and fallopian tube cancer in high-risk women, although there is a substantial residual risk for peritoneal cancer in BRCA1 and BRCA2 mutation carriers following prophylactic salpingo-oophorectomy.

Adult↗
PubMed2006

Tamoxifen and contralateral breast cancer in BRCA1 and BRCA2 carriers: an update.

Women with a mutation in BRCA1 or BRCA2 face a lifetime risk of breast cancer of approximately 80%, and following the first diagnosis the 10-year risk of contralateral breast cancer is approximately 30%. It has been shown that both tamoxifen and oophorectomy prevent contralateral breast cancer, but it is not clear whether there is a benefit in giving tamoxifen to women who have previously undergone an oophorectomy. Furthermore, the relative degree of protection in BRCA1 and BRCA2 carriers has not been well evaluated. We studied 285 women with bilateral breast cancer and a BRCA1 or BRCA2 mutation, and 751 control women with unilateral breast cancer and a BRCA1 or BRCA2 mutation in a matched case-control study. Control women were of similar age and had a similar age of diagnosis of breast cancer and had been followed for as long as the case for a second primary breast cancer. The history of tamoxifen use for treating the first breast cancer was compared between bilateral and unilateral cases. The multivariate odds ratio for contralateral breast cancer associated with tamoxifen use was 0.50 for carriers of BRCA1 mutations (95% CI, 0.30-0.85) and was 0.42 for carriers of BRCA2 mutations (95% CI, 0.17-1.02). The protective effect of tamoxifen was not seen among women who had undergone an oophorectomy (OR = 0.83; 95%CI, 0.24-2.89) but this subgroup was small. In contrast, a strong protective effect of tamoxifen was apparent among women who were premenopausal or who had undergone natural menopause (OR = 0.44; 95% CI, 0.27-0.65).

Adult↗
PubMed2006

Spontaneous and therapeutic abortions and the risk of breast cancer among BRCA mutation carriers.

INTRODUCTION: BRCA1 and BRCA2 mutation carriers are at increased risk for developing both breast and ovarian cancer. It has been suggested that carriers of BRCA1/2 mutations may also be at increased risk of having recurrent (three or more) miscarriages. Several reproductive factors have been shown to influence the risk of breast cancer in mutation carriers, but the effects of spontaneous and therapeutic abortions on the risk of hereditary breast cancer risk have not been well studied to date. METHODS: In a matched case-control study, the frequencies of spontaneous abortions were compared among 1,878 BRCA1 mutation carriers, 950 BRCA2 mutation carriers and 657 related non-carrier controls. The rates of spontaneous and therapeutic abortions were compared for carriers with and without breast cancer. RESULTS: There was no difference in the rate of spontaneous abortions between carriers of BRCA1 or BRCA2 mutations and non-carriers. The number of spontaneous abortions was not associated with breast cancer risk among BRCA1 or BRCA2 mutation carriers. However, BRCA2 carriers who had two or more therapeutic abortions faced a 64% decrease in the risk of breast cancer (odds ratio = 0.36; 95% confidence interval 0.16-0.83; p = 0.02). CONCLUSION: Carrying a BRCA1 or BRCA2 mutation is not a risk factor for spontaneous abortions and spontaneous abortions do not appear to influence the risk of breast cancer in carriers of BRCA1 or BRCA2 mutations. However, having two or more therapeutic abortions may be associated with a lowered risk of breast cancer among BRCA2 carriers.

Abortion, Spontaneous↗
PubMed2006

Coffee consumption and breast cancer risk among BRCA1 and BRCA2 mutation carriers.

Although there are several plausible biologic mechanisms whereby coffee consumption might influence the risk of breast cancer, epidemiologic evidence is limited. We assessed the association between coffee consumption and breast cancer risk among high-risk women who carry BRCA mutations. We performed a matched case-control analysis on 1,690 women with a BRCA1 or BRCA2 mutation from 40 centers in 4 countries. Average lifetime coffee consumption was estimated via a self-administered questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression. After adjustment for potential confounders, the ORs for breast cancer in BRCA carriers who habitually drank 0, 1-3, 4-5 and 6 or more cups of coffee were 1.00, 0.90 (95% CI 0.72-1.12), 0.75 (95% CI 0.47-1.19) and 0.31 (95% CI 0.13-0.71; p-trend = 0.02). The effect was limited to the consumption of caffeinated coffee. These results suggest that among women with BRCA gene mutation, coffee consumption is unlikely to be harmful and that high levels of consumption may in fact be related to reduced breast cancer risk.

Adult↗
PubMed2005

Effect of pregnancy as a risk factor for breast cancer in BRCA1/BRCA2 mutation carriers.

Early age at first birth and multiparity have been associated with a decrease in the risk of breast cancer in women in the general population. We examined whether this relationship is also present in women at high risk of breast cancer due to the presence of a mutation in either of the 2 breast cancer susceptibility genes, BRCA1 or BRCA2. We performed a matched case-control study of 1,260 pairs of women with known BRCA1 or BRCA2 mutations, recruited from North America, Europe and Israel. Women who had been diagnosed with breast cancer were matched with unaffected control subjects for year of birth, country of residence, and mutation (BRCA1 or BRCA2). Study subjects completed a questionnaire detailing their reproductive histories. Odds ratios (ORs) and 95% confidence intervals (CIs) were derived by conditional logistic regression. Among BRCA1 carriers, parity per se was not associated with the risk of breast cancer (OR for parous vs. nulliparous = 0.94; 95% CI = 0.75-1.19; p = 0.62). However, women with a BRCA1 mutation and 4 or more children had a 38% decrease in breast cancer risk compared to nulliparous women (OR = 0.62; 95% CI = 0.41-0.94). In contrast, among BRCA2 carriers, increasing parity was associated with an increased risk of breast cancer; women with 2 or more children were at approximately 1.5 times the risk of breast cancer as nulliparous women (OR = 1.53; 95% CI = 1.01-2.32; p = 0.05). Among women with BRCA2 mutations and who were younger than age 50, the (adjusted) risk of breast cancer increased by 17% with each additional birth (OR = 1.17; 95% CI = 1.01-1.36; p = 0.03). There was no significant increase in the risk of breast cancer among BRCA2 carriers older than 50 (OR for each additional birth = 0.97; 95% CI = 0.58-1.53; p = 0.92). In the 2-year period following a birth, the risk of breast cancer in a BRCA2 carrier was increased by 70% compared to nulliparous controls (OR = 1.70; 95% CI = 0.97-3.0). There was a much smaller increase in breast cancer risk among BRCA2 carriers whose last birth was 5 or more years in the past (OR = 1.24; 95% CI = 0.79-1.95). A modest reduction in risk of breast cancer was observed among BRCA1 carriers with 4 or more births. Among BRCA2 carriers, increasing parity was associated with a significant increase in the risk of breast cancer before age 50 and this increase was greatest in the 2-year period following a pregnancy.

Adolescent↗
PubMed2005

Breast cancer risk following bilateral oophorectomy in BRCA1 and BRCA2 mutation carriers: an international case-control study.

PURPOSE: The purpose of this study was to estimate the extent of protection offered against breast cancer by prophylactic oophorectomy in carriers of BRCA1 or BRCA2 mutations and to determine to what extent risk reduction varies with age at oophorectomy, age at diagnosis, and time elapsed since surgery. PATIENTS AND METHODS: We analyzed 1,439 patients with breast cancer and 1,866 matched controls derived from a registry of BRCA1 and BRCA2 carriers. We estimated odds ratios (ORs) of breast cancer for having had a bilateral oophorectomy, using conditional logistic regression, matched for parity and for oral contraceptive use. RESULTS: A previous history of oophorectomy was associated with a significant reduction in breast cancer risk of 56% for BRCA1 carriers (OR = 0.44; 95% CI, 0.29 to 0.66) and of 46% for BRCA2 carriers (OR = 0.57; 95% CI, 0.28 to 1.15). The risk reduction was greater if the oophorectomy was performed before age 40 (OR = 0.36; 95% CI, 0.20 to 0.64 for BRCA1 carriers) than after age 40 (OR = 0.53; 95% CI, 0.30 to 0.91). The protective effect was evident for 15 years post-oophorectomy (OR = 0.39; 95% CI, 0.26 to 0.57). CONCLUSION: Oophorectomy is an effective means of reducing the risk of breast cancer in carriers of BRCA1 mutations. The data suggest oophorectomy is protective in BRCA2 carriers as well, but needs to be confirmed in other studies.

Adult↗
PubMed2005

Hormone replacement therapy and the risk of ovarian cancer in BRCA1 and BRCA2 mutation carriers.

OBJECTIVE: Hormone replacement therapy (HRT) is commonly prescribed to alleviate the climacteric symptoms of menopause. Recent findings from the Women's Health Initiative has raised questions about the routine use of HRT due to the increased observed incidence of cardiovascular disease and of breast and ovarian cancers in the treatment arm of the trial. In the general population, the association between HRT use and risk of ovarian cancer has not yet been resolved. This association has not been evaluated in BRCA1 or BRCA2 mutation carriers who face very high lifetime risks of both breast and ovarian cancers. METHODS: We conducted a matched case-control study on 162 matched sets of women who carry a deleterious mutation in either the BRCA1 or BRCA2 gene. Women who had been diagnosed with ovarian cancer were matched to control subjects by mutation, year of birth, and age at menopause. Information on HRT use was derived from a questionnaire routinely administered to women who were found to be carriers of a mutation in either gene. Conditional logistic regression was used to estimate the association between HRT use and the risk of ovarian cancer, stratified by mutation status and type of HRT. RESULTS: Compared with those who had never used HRT, the odds ratio associated with ever use of HRT was 0.93 (95% CI = 0.56-1.56). There was no significant relationship with increasing duration of HRT use. There was a suggestion that progestin-based HRT regimens might protect against ovarian cancer (odds ratio = 0.57) but this association was not statistically significant (P = 0.20). CONCLUSION: HRT use does not appear to adversely influence the risk of ovarian cancer in BRCA mutation carriers.

Aged↗
PubMed2005

Changes in body weight and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers.

BACKGROUND: Several anthropometric measures have been found to be associated with the risk of breast cancer. Current weight, body mass index, and adult weight gain appear to be predictors of postmenopausal breast cancer. These factors have been associated with a reduced risk of premenopausal breast cancer. We asked whether there is an association between changes in body weight and the risk of breast cancer in women who carry a mutation in either breast cancer susceptibility gene, BRCA1 or BRCA2. METHODS: A matched case-control study was conducted in 1,073 pairs of women carrying a deleterious mutation in either BRCA1 (n = 797 pairs) or BRCA2 (n = 276 pairs). Women diagnosed with breast cancer were matched to control subjects by year of birth, mutation, country of residence, and history of ovarian cancer. Information about weight was derived from a questionnaire routinely administered to women who were carriers of a mutation in either gene. Conditional logistic regression was used to estimate the association between weight gain or loss and the risk of breast cancer, stratified by age at diagnosis or menopausal status. RESULTS: A loss of at least 10 pounds in the period from age 18 to 30 years was associated with a decreased risk of breast cancer between age 30 and 49 (odds ratio (OR) = 0.47; 95% confidence interval (CI) 0.28-0.79); weight gain during the same interval did not influence the overall risk. Among the subgroup of BRCA1 mutation carriers who had at least two children, weight gain of more than 10 pounds between age 18 and 30 was associated with an increased risk of breast cancer diagnosed between age 30 and 40 (OR = 1.44, 95% CI 1.01-2.04). Change in body weight later in life (at age 30 to 40) did not influence the risk of either premenopausal or postmenopausal breast cancer. CONCLUSION: The results from this study suggest that weight loss in early adult life (age 18 to 30) protects against early-onset BRCA-associated breast cancers. Weight gain should also be avoided, particularly among BRCA1 mutation carriers who elect to have at least two pregnancies.

Adolescent↗
PubMed2005

Age at menarche and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers.

Age at menarche is a strong and consistent predictor of breast cancer risk in the general population, but has not been well studied in women with a family history of breast cancer. We conducted this study to examine whether the presence of a deleterious BRCA1 or BRCA2 mutation influences age at menarche and to investigate whether or not there is an association between age at menarche and the risk of breast cancer in BRCA1 or BRCA2 mutation carriers. The presence of a deleterious BRCA1 or BRCA2 mutation did not appear to influence a woman's age at menarche. A matched case-control study was conducted on 1311 pairs of women who have been identified to be carriers of a deleterious mutation in either the BRCA1 (n = 945 pairs) or the BRCA2 gene (n = 366 pairs). Information about age at menarche was derived from a questionnaire routinely administered to carriers of a mutation in either gene. Among women who carried a deleterious BRCA1 mutation, age at menarche was inversely associated with the risk of breast cancer (p trend = 0.0002). This association was not observed among BRCA2 mutation carriers (p trend = 0.49). Compared with BRCA1 carriers whose age at menarche was < or =11 years, women with a menarcheal age between 14 and 15 years old had a 54% reduction in risk (OR = 0.46; 95% CI 0.30-0.69). This study implicates early age at menarche as a determinant of breast cancer among women with a BRCA1 mutation.

Adolescent↗
PubMed2004

Smoking and the risk of breast cancer among carriers of BRCA mutations.

The effect of cigarette smoking on the risk of breast cancer is controversial, although most studies show little or no effect. It has been suggested that smoking may reduce the risk of developing hereditary breast cancer. We completed a case-control study on 1,097 women with breast cancer who were BRCA1 or BRCA2 mutation carriers and 1,097 age-matched controls with a mutation in the same gene but without breast cancer. There were no statistically significant differences between the cases and controls in terms of the number of current and ex-smokers (41.2% and 40.4%, respectively) or the age at smoking commencement (18.2 years and 18.5 years, respectively). There were no statistically significant differences between cases and controls regarding beginning smoking within 5 years of menarche (OR = 1.03; 95% CI 0.83 to l.28) or before the first pregnancy (OR = 1.09; 95% CI = 0.90 to 1.33). In conclusion, contrary to our previous report, smoking does not appear to be a risk factor for breast cancer among carriers of BRCA mutations.

Adolescent↗
PubMed2003

Alternatively spliced, truncated human BRCA2 isoforms contain a novel coding exon.

The protein truncation test (PTT) employs in vitro transcription and translation of amplified cDNA and exonic gDNA to reveal truncating germ-line mutations. In a series of PTT analyses, abnormal splicing in the region encompassing exons 20-23 of BRCA2 was discovered in leucocytes from high-risk breast cancer patients. Although sequencing of the genomic DNA in this region failed to reveal a detectable mutation in these patients, cDNA obtained from this region of BRCA2 uncovered numerous alternative splice isoforms. PTT analysis and nested RT-PCR using RNA from leucocytes from healthy individuals, normal tissue and breast and ovarian cancer tumours demonstrated the presence of these alternatively spliced transcripts in all cases. The splice forms appeared to be more prominent in RNA from aged blood, suggesting that isoform expression was conditional. It is therefore important to distinguish naturally occurring alternative splicing from true splice defects due to mutations when interpreting PTT results.

Alternative Splicing↗
PubMed2002

Oral contraceptives and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers.

BACKGROUND: Oral contraceptive use has been associated with an increase in the risk of breast cancer in young women. We examined whether this association is seen in women at high risk of breast cancer because they carry a mutation in one of two breast cancer susceptibility genes, BRCA1 and BRCA2. METHODS: We performed a matched case-control study on 1311 pairs of women with known deleterious BRCA1 and/or BRCA2 mutations recruited from 52 centers in 11 countries. Women who had been diagnosed with breast cancer were matched to control subjects by year of birth, country of residence, mutation (BRCA1 or BRCA2), and history of ovarian cancer. All study subjects completed a questionnaire about oral contraceptive use. Odds ratios (ORs) and 95% confidence intervals (CIs) were derived by conditional logistic regression. All statistical tests were two-sided. RESULTS: Among BRCA2 mutation carriers, ever use of oral contraceptives was not associated with an increased risk of breast cancer (OR = 0.94, 95% CI = 0.72 to 1.24). For BRCA1 mutation carriers, ever use of oral contraceptives was associated with a modestly increased risk of breast cancer (OR = 1.20, 95% CI = 1.02 to 1.40). However, compared with BRCA1 mutation carriers who never used oral contraceptives, those who used oral contraceptives for at least 5 years had an increased risk of breast cancer (OR = 1.33, 95% CI = 1.11 to 1.60), as did those who used oral contraceptives before age 30 (OR = 1.29, 95% CI = 1.09 to 1.52), those who were diagnosed with breast cancer before age 40 (OR = 1.38, 95% CI = 1.11 to 1.72), and those who first used oral contraceptives before 1975 (OR = 1.42, 95% CI = 1.17 to 1.75). CONCLUSIONS: Among BRCA1 mutation carriers, women who first used oral contraceptives before 1975, who used them before age 30, or who used them for 5 or more years may have an increased risk of early-onset breast cancer. Oral contraceptives do not appear to be associated with risk of breast cancer in BRCA2 carriers, but data for BRCA2 carriers are limited.

Adolescent↗