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Steven A Narod

Publications and source records attributed to Steven A Narod.

101 records · Page 6Linked to original sources
PubMed2002

Risk of pancreatic cancer among individuals with a family history of cancer of the pancreas.

In a hospital based case-control study of pancreatic cancer in Ontario and Quebec, a total of 174 incident pancreatic cancer cases and 136 healthy controls were compared for their family history of cancer. Information regarding the ages and sites of cancer was taken for 966 first-degree relatives of the cancer cases and for 903 first-degree relatives of the controls. A total of 150 cancer cases were reported among the relatives of the cases, compared to 122 cases among the relatives of the controls (relative risk 1.15; p = 0.23). Pancreatic cancer was the only site statistically in excess in the case relatives, compared to the control relatives (relative risk = 5.0; p = 0.01). The lifetime risk of pancreatic cancer was 4.7% for the first-degree relatives of the pancreatic cancer cases. The risk was 7.2% for relatives of cases diagnosed before age 60, and was 12.3% for relatives of patients with multiple primary cancers (all ages). These individuals comprise a high-risk group for pancreatic cancer and might benefit from enhanced surveillance or chemoprevention. Familial site-specific pancreatic cancer appears to be a distinct genetic entity, but contributes only modestly to the total burden of pancreatic cancer.

Adult↗
PubMed2002

Evaluation of linkage of breast cancer to the putative BRCA3 locus on chromosome 13q21 in 128 multiple case families from the Breast Cancer Linkage Consortium.

The known susceptibility genes for breast cancer, including BRCA1 and BRCA2, only account for a minority of the familial aggregation of the disease. A recent study of 77 multiple case breast cancer families from Scandinavia found evidence of linkage between the disease and polymorphic markers on chromosome 13q21. We have evaluated the contribution of this candidate "BRCA3" locus to breast cancer susceptibility in 128 high-risk breast cancer families of Western European ancestry with no identified BRCA1 or BRCA2 mutations. No evidence of linkage was found. The estimated proportion (alpha) of families linked to a susceptibility locus at D13S1308, the location estimated by Kainu et al. [(2000) Proc. Natl. Acad. Sci. USA 97, 9603-9608], was 0 (upper 95% confidence limit 0.13). Adjustment for possible bias due to selection of families on the basis of linkage evidence at BRCA2 did not materially alter this result (alpha = 0, upper 95% confidence limit 0.18). The proportion of linked families reported by Kainu et al. (0.65) is excluded with a high degree of confidence in our dataset [heterogeneity logarithm of odds (HLOD) at alpha = 0.65 was -11.0]. We conclude that, if a susceptibility gene does exist at this locus, it can only account for a small proportion of non-BRCA1/2 families with multiple cases of early-onset breast cancer.

Australia↗
PubMed2002

A low frequency of non-founder BRCA1 mutations in Ashkenazi Jewish breast-ovarian cancer families.

The 185delAG and 5382insC founder mutations account for the majority of mutations identified in BRCA1 in Ashkenazi Jewish breast and breast-ovarian cancer families. Few non-founder BRCA1 mutations have been identified to date in these families. We initially screened a panel of 245 Ashkenazi Jewish breast-ovarian cancer families with an affected proband and at least one other case of breast or ovarian cancer for founder mutations in BRCA1 and BRCA2. Founder mutations were identified in 85 families (185delAG in 44 families, 5382insC in 16 families, and the BRCA2 6174delT in 25 families). The 160 negative families were then screened for the entire BRCA1 gene by a combination of DGGE and PTT. We identified one novel frameshift mutation in BRCA1 in exon 14 (4572del22) that truncated the protein at codon 1485. The family contained three cases of early-onset ovarian cancer (41 years, 43 years, and 52 years) and one case of breast cancer (at age 54 years subsequent to an ovarian cancer). In addition, three missense variants of unknown significance (exon 11 C3832T (P1238L), exon 15 G4654T (S1512I), and exon 15 G4755A (D1546N)) were found in single families. These missense variants have been previously identified in other families [BIC Database] and are considered to be "unclassified variants, favoring polymorphism." Non-founder BRCA1 mutations are rare in Ashkenazi Jewish breast/ovarian cancer families.

Adult↗
PubMed2002

Hereditary breast and ovarian cancer in Asia: genetic epidemiology of BRCA1 and BRCA2.

Ethnic differences in cancer incidence and mortality result from differences in genetic and epidemiologic risk factors. Mutations in BRCA1 and BRCA2 account for a small proportion of all breast cancer cases, but for a much higher proportion of cases with a strong family history of breast or ovarian cancer. Germline mutations in BRCA1 and BRCA2 have been identified in individuals of many races and ethnic groups and the frequency of mutations varies between these groups. Some of the differences in cancer risk between populations may be the result of founder mutations in these genes. The cost and time required for mutation analysis are reduced considerably when founder mutations are identified for a specific ethnic group. The BRCA2 999del5 mutation in Iceland and three BRCA mutations in Ashkenazi Jews are well characterized. However, considerably less is known about the contribution of mutations in the BRCA1 and BRCA2 genes outside of European groups. Studies conducted on the Asian populations described here have expanded our current knowledge of genetic susceptibility and its contribution to breast and ovarian cancer rates in Asian populations.

Asia↗
PubMed2002

A BRCA1 mutation in Native North American families.

Germline mutations in the BRCA1 (MIM 113705) and BRCA2 (MIM 600185) genes have been identified for breast and ovarian cancer families of diverse ethnic backgrounds. To date, there have been no reports of Native North American families with mutations in BRCA1 or BRCA2. Here we report two families of aboriginal descent both with the same BRCA1 alterations (1510insG, 1506A>G). The families represent two aboriginal Canadian tribes (Cree and Ojibwe), although a common ancestral origin is likely. This is the first evidence of a BRCA1 mutation specific to aboriginal peoples of North America.

Alleles↗
PubMed2002

Modifiers of risk of hereditary breast and ovarian cancer.

Hereditary breast and ovarian cancer is among the most commonly encountered adult genetic disease, and it is increasingly important that geneticists, oncologists, surgeons and gynaecologists are aware of the issues regarding risk assessment, prevention and management of women with inherited susceptibility to cancer. Genetic risk can be modified by external factors, but what are these factors, and how might our knowledge of them help us to better define the risks for individual women and to develop strategies for cancer prevention?

Alleles↗
PubMed2002

Current understanding of the epidemiology and clinical implications of BRCA1 and BRCA2 mutations for ovarian cancer.

Genetic testing for susceptibility to ovarian cancer is rapidly becoming integrated into the clinical practice of oncology. Genetic testing for BRCA1 and BRCA2 is now recommended to most women with invasive ovarian cancer. Approximately 10% of these women will have a positive test, including 4% of women without a family history of cancer. Currently, the treatment of hereditary ovarian cancer is the same as for non-hereditary ovarian cancer. It appears that women with ovarian cancer and a BRCA mutation experience better survival than women without a mutation, possibly due to enhanced susceptibility to chemotherapy. Strategies for prevention of ovarian cancer among carriers include oral contraceptives, tubal ligation and prophylactic oophorectomy.

Biomarkers, Tumor↗
PubMedDate not supplied

Predictors of quality of life in women with a bilateral prophylactic mastectomy.

The purpose of this study was to assess the quality of life in women who had previously undergone a bilateral prophylactic mastectomy and to determine what factors predict quality of life in this population. Women in Ontario who had undergone prophylactic mastectomy between 1991 and 2000 were asked to complete several questionnaires that assessed current psychosocial functioning, including the Quality of Life Index (QLI). The mean score for the QLI was 23.34 (range 9.53-30.00). QLI scores were negatively correlated with cancer-related distress, body image difficulties, and psychological distress. Conversely, QLI scores were positively correlated with social support. Significant predictors of quality of life included psychological distress and one subscale of body image (vulnerability). Vulnerability and psychological distress are important predictors of quality of life in women who have previously undergone bilateral prophylactic mastectomy.

Adult↗
PubMedDate not supplied

The role of reexcision for positive margins in optimizing local disease control after breast-conserving surgery for cancer.

One of the most important factors associated with local recurrence after lumpectomy in breast cancer patients is the status of the surgical margin. Standard surgical practice is to obtain clear margins even if this requires a second surgical procedure. It is assumed that reexcision to achieve clear margins when positive margins are present at initial excision is as effective as complete tumor removal at a single procedure; however, the efficacy of reexcision in this context has not been well studied. A retrospective search of the Henrietta Banting Breast Centre database from 1987 to 1997 identified 1430 patients who underwent lumpectomy for invasive breast cancer: 1225 patients (group A) had negative margins at the initial surgery and 152 patients (group B) underwent one or more reexcisions to achieve negative margins. Fifty-three patients had positive margins at final surgery, but no reexcision was done (group C). Logistic regression was used to identify factors that were predictive of a positive margin; predictors of local recurrence in women whose tumors were completely resected were determined using Cox's proportional hazards model. Patients in groups A, B, and C differed with respect to mean age at diagnosis (58 years, 51 versus, and 56 years, respectively, p < 0.0001), mean tumor size (19 mm, 16 mm, and 26 mm, respectively, p < 0.0001), node positivity (30%, 22%, and 41%, respectively, p = 0.004), and the presence of a ductal carcinoma in situ (DCIS) component (60%, 64%, and 79%, respectively, p = 0.007). The mean follow-up period was similar for the three groups (8 years, 8 years, and 9 years, respectively, p = 0.17). Young age was the only variable predictive of positive margins. Among patients undergoing complete tumor excision, there was a suggestion of a higher 10 year local recurrence rate in reexcision group B, but the difference did not reach statistical significance (11.6% versus 16.6%, p = 0.11). Cox's multivariate regression analyses identified older age, smaller tumor size, receiving radiation therapy, and tamoxifen use as significantly decreasing the rate of local recurrence in patients with negative margins at initial surgery or after reexcision. Our data confirm the results of previous studies indicating that young age is an independent predictor of positive margins after lumpectomy for invasive breast cancer. The only independent predictor of local recurrence in our study cohort was large tumor size. There was a trend toward a higher local recurrence rate if more than one procedure was required to secure clear margins, although this effect was not independent of other factors. Reexcision to clear involved margins is an important surgical intervention for both younger and older women.

Breast Neoplasms↗