Journal of clinical oncology : official journal of the American Society of Clinical Oncology
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Randomized Controlled Trial Comparative Study Clinical Trial
Letrozole is more effective neoadjuvant endocrine therapy than tamoxifen for ErbB-1- and/or ErbB-2-positive, estrogen receptor-positive primary breast cancer: evidence from a phase III randomized trial.
Expression of ErbB-1 and ErbB-2 (epidermal growth factor receptor and HER2/neu) in breast cancer may cause tamoxifen resistance, but not all studies concur. Additionally, the relationship between ErbB-1 and ErbB-2 expression and response to selective aromatase inhibitors is unknown. A neoadjuvant study for primary breast cancer that randomized treatment between letrozole and tamoxifen provided a context within which these issues could be addressed prospectively. ⋯ ER+, ErbB-1+, and/or ErbB-2+ primary breast cancer responded well to letrozole, but responses to tamoxifen were infrequent. This suggests that ErbB-1 and ErbB-2 signaling through ER is ligand-dependent and that the growth-promoting effects of these receptor tyrosine kinases on ER+ breast cancer can be inhibited by potent estrogen deprivation therapy.
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Validated quantitative models are available that permit the accurate estimation of a woman's risk of developing invasive breast cancer during a specified period of time. Data from the National Surgical Adjuvant Breast and Bowel Project Breast Cancer Prevention Trial indicate that tamoxifen can reduce the risk of developing breast cancer by at least 49% in women who are at increased risk. All premenopausal women whose 5-year risk of developing breast cancer is 1.67% or greater derive a net benefit from taking tamoxifen for risk reduction. ⋯ Women who carry mutations in either the BRCA1 or BRCA2 gene will also experience reduced incidence of breast cancer with tamoxifen. Although postmenopausal women derive a net benefit from tamoxifen through the reduction of both breast cancer and bone fracture event rates, the risks of both invasive endometrial cancer and thromboembolic events must be balanced in older women. Physicians should identify appropriate candidates with whom to discuss the possible benefits of tamoxifen for reducing the risk of breast cancer.
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To determine the incidence and the prognostic value of ipsilateral breast tumor recurrence (IBTR) in patients treated with primary chemotherapy and breast-conserving surgery. ⋯ IBTR is a strong predictor for distant metastases. There are implications for conservative surgery after downstaging of the tumor and therapy at the time of IBTR.
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One of every three persons who starts smoking falls ill and dies prematurely because he or she smoked. Smoking has been causally linked to heart disease, cancer, and respiratory diseases and continues to be the number one preventable cause of death in this country. To prevent these deaths and the incidence of these diseases, California's Tobacco Control Program was established in 1989 specifically to reduce tobacco use in the state. ⋯ However, contrary to the message of its massive public relations campaign, the tobacco industry has not changed its stripes after the national tobacco settlement. They are still aggressively marketing their products to teenagers, ethnic minority groups, and young adults. They need to be combatted with renewed vigor by a vigilant health community.
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Lung cancer is the leading cause of cancer deaths in the United States and the world, with grim incidence and mortality figures underscoring the need for new approaches, such as chemoprevention, for controlling this disease. There have been definitive, randomized, controlled lung-cancer chemoprevention trials in the three chemoprevention trial settings: primary (healthy high-risk [eg, smokers]), secondary (premalignant lesions), and tertiary (prevention of second primary tumors in previously treated patients), all of which produced negative (either neutral or harmful) primary end point results. ⋯ A major area of lung cancer research is molecular epidemiologic study of highest smoking-related risk based on the interactions between tobacco carcinogens, genetic polymorphisms involved in activating and detoxifying these carcinogens, and host-cell efficiency in monitoring and repairing tobacco carcinogen-DNA damage. The future of lung cancer chemoprevention will rely heavily on molecular studies of carcinogenesis and drug mechanisms to develop novel chemopreventive targets and drugs, risk markers, and surrogate end point biomarkers; new preclinical drug-testing models; novel imaging techniques for monitoring agent activity; and molecular epidemiologic risk models for identifying the highest-risk current and former smokers.