Breast cancer prevention strategies in lobular carcinoma in situ: A decision analysis.

BACKGROUND: Women diagnosed with lobular carcinoma in situ (LCIS) have a 3-fold to 10-fold increased risk of developing invasive breast cancer. The objective of this study was to evaluate the life expectancy (LE) and differences in survival offered by active surveillance, risk-reducing chemoprevention, and bilateral prophylactic mastectomy among women with LCIS.

METHODS: A Markov simulation model was constructed to determine average LE and quality-adjusted LE (QALE) gains for hypothetical cohorts of women diagnosed with LCIS at various ages under alternative risk-reduction strategies. Probabilities for invasive breast cancer, breast cancer-specific mortality, other-cause mortality and the effectiveness of preventive strategies were derived from published studies and from the National Cancer Institute's Surveillance, Epidemiology, and End Results database.

RESULTS: Assuming a breast cancer incidence from 1.02% to 1.37% per year under active surveillance, a woman aged 50 years diagnosed with LCIS would have a total LE of 32.78 years and would gain 0.13 years (1.6 months) in LE by adding chemoprevention and 0.25 years (3.0 months) in LE by adding bilateral prophylactic mastectomy. After quality adjustment, chemoprevention resulted in the greatest QALE for women ages 40 to 60 years at LCIS diagnosis, whereas surveillance remained the preferred strategy for optimizing QALE among women diagnosed at age 65 years and older.

CONCLUSIONS: In this model, among women with a diagnosis of LCIS, breast cancer prevention strategies only modestly affected overall survival, whereas chemoprevention was modeled as the preferred management strategy for optimizing invasive disease-free survival while prolonging QALE form women younger than 65 years. Cancer 2017;123:2609-17. © 2017 American Cancer Society.