Journal of the National Cancer Institute
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J. Natl. Cancer Inst. · Jan 2006
Endogenous sex hormones, breast cancer risk, and tamoxifen response: an ancillary study in the NSABP Breast Cancer Prevention Trial (P-1).
Prospective studies have shown an association between increased serum levels of estradiol and testosterone and breast cancer risk in postmenopausal women. Raloxifene has been shown to reduce breast cancer risk more in women with high estradiol levels than in those with lower levels. The purpose of this study was to determine whether sex hormone levels were associated with breast cancer risk and with response to tamoxifen in a high-risk population. ⋯ These data do not support the use of endogenous sex hormone levels to identify women who are at particularly high risk of breast cancer and who are most likely to benefit from chemoprevention with tamoxifen.
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J. Natl. Cancer Inst. · Jan 2006
Population-based study of changing breast cancer risk in Icelandic BRCA2 mutation carriers, 1920-2000.
Mutations in the BRCA genes increase the risk of breast cancer. Valid estimates of the magnitude of the lifetime risk of breast cancer in BRCA gene mutation carriers are needed for genetic counseling. Recent results suggest that penetrance has increased in recent birth cohorts. We examined the cumulative breast cancer incidence and mortality before age 70 over a diagnosis period of 80 years in Icelandic women who carried the BRCA2 founder mutation 999del5. ⋯ The results indicate that the penetrance of the Icelandic BRCA2 founder mutation increased nearly fourfold in 80 years, whereas the risk of death from breast cancer before age 70 years increased only approximately twofold. Changes in penetrance with time should be considered when penetrance is estimated.
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J. Natl. Cancer Inst. · Jan 2006
Meta AnalysisSurvival effects of postmastectomy adjuvant radiation therapy using biologically equivalent doses: a clinical perspective.
Postmastectomy radiation therapy reduces locoregional recurrence among women with operable breast cancer, but whether it improves survival has been controversial. We reanalyzed the results from 36 unconfounded trials (i.e., addition of radiation therapy was the sole discriminant between treatments being compared) that were identified in previous meta-analyses, which provided 38 comparisons. ⋯ Adjuvant radiation therapy with an optimal BED and target volume was statistically significantly associated with improved survival for up to 10 years.
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J. Natl. Cancer Inst. · Jan 2006
Cholesterol-lowering drugs and colorectal cancer incidence in a large United States cohort.
3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, commonly known as statins, account for most cholesterol-lowering drug use in the United States. A recent large case-control study reported that use of statins for more than 5 years was associated with a 47% reduction in risk of colorectal cancer. No other large studies have examined this association. ⋯ Current use of cholesterol-lowering drugs for 5 years or more was also not associated with colorectal cancer incidence (multivariable adjusted RR = 1.09, 95% CI = 0.83 to 1.43). Our results do not support the hypothesis that statin use strongly reduces risk of colorectal cancer. However, we cannot rule out a small reduction in risk or an effect associated with only specific types or doses of statins.