Use of pharmacologic interventions for breast cancer risk reduction: American Society of Clinical Oncology clinical practice guideline.
Level 1 - systematic review of randomized trials
Systematic review of randomized controlled trials and meta-analyses
PubMed 23835710 · doi:10.1200/JCO.2013.49.3122
What was done
The American Society of Clinical Oncology (ASCO) updated its 2009 clinical practice guideline through a systematic review of randomized controlled trials and meta-analyses published between June 2007 and June 2012 in MEDLINE and the Cochrane Library. The primary outcome evaluated was breast cancer incidence (invasive and noninvasive); secondary outcomes included breast cancer mortality, adverse events, and net health benefits across six pharmacologic agents (tamoxifen, raloxifene, arzoxifene, lasofoxifene, exemestane, and anastrozole).
What was found
The review included 19 articles. The abstract provides no quantitative effect estimates or risk ratios. Based on the evidence, the panel recommended: tamoxifen (20 mg/day for 5 years) for women aged ≥ 35 years at increased risk to reduce estrogen receptor-positive breast cancer; and raloxifene (60 mg/day for 5 years) or exemestane (25 mg/day for 5 years) for postmenopausal women at increased risk. Increased risk was defined as a 5-year projected absolute breast cancer risk ≥ 1.66% or a diagnosis of lobular carcinoma in situ. Other selective estrogen receptor modulators or aromatase inhibitors were not recommended outside of clinical trials.
Why it matters
This guideline defines evidence-based pharmacologic prevention strategies and standardizes high-risk criteria (5-year absolute risk ≥ 1.66%) to assist shared clinical decision-making.
Limits
The abstract reports no numerical effect sizes, absolute risk reductions, or specific adverse event rates. Recommendations are limited to high-risk populations and primarily target estrogen receptor-positive disease, with the literature search restricted to studies published through June 2012.