Modeling the effectiveness of initial management strategies for ductal carcinoma in situ

Abstract

Background: The prevalence of ductal carcinoma in situ (DCIS) and the marked variability in patterns of care highlight the need for comparative effectiveness research. We sought to quantify the tradeoffs among alternative management strategies for DCIS with respect to disease outcomes and breast preservation.

Methods: We developed a disease simulation model integrating data from the published literature to simulate the clinical events after six treatments (lumpectomy alone, lumpectomy with radiation, lumpectomy with radiation and tamoxifen, lumpectomy with tamoxifen, and mastectomy with and without breast reconstruction) for women with newly diagnosed DCIS. Outcomes included disease-free, invasive disease-free, and overall survival and breast preservation.

Results: For a cohort of 1 million simulated women aged 45 years at diagnosis, both mastectomy and lumpectomy with radiation and tamoxifen were associated with a 12-month improvement in overall survival relative to lumpectomy alone. Adding radiation therapy to lumpectomy resulted in a 6-month improvement in overall survival but decreased long-term breast-preservation outcomes (likelihood of lifetime breast preservation = 0.781 vs 0.843 for lumpectomy alone). This decrement with radiation therapy was mitigated by the addition of tamoxifen (likelihood of lifetime breast preservation = 0.846).

Conclusions: Overall survival benefits of the six management strategies for DCIS are within 1 year, suggesting that treatment decisions can be informed by the patient's preference for breast preservation and disutility for recurrence. Our delineation of personalized outcomes for each strategy can help patients understand the implications of their treatment choice, so their decisions may reflect their own personal values and help improve the quality of care for patients with DCIS.

Figure 1.

Discrete event simulation schematic. *Death can be from breast cancer or non–breast cancer causes. Only women with an invasive diagnosis can die from breast cancer. DCIS = ductal carcinoma in situ; LO = lumpectomy alone; LO + TAM = lumpectomy with tamoxifen; LRT = lumpectomy with radiation; LRT + TAM = lumpectomy with radiation and tamoxifen; MTX = mastectomy; MTX + Recon = mastectomy with reconstruction.

Figure 2.

Death from breast cancer for the different treatment strategies over time. LO = lumpectomy alone; LO + TAM = lumpectomy with tamoxifen; LRT = lumpectomy with radiation; LRT + TAM = lumpectomy with radiation and tamoxifen; MTX = mastectomy; Recon = reconstruction.

Figure 3.

The impact of varying the likelihood of mastectomy after a recurrence in an unirradiated breast on lifetime ipsilateral breast preservation. The lumpectomy (LO) and lumpectomy with tamoxifen (LO + TAM) curves overlap in this figure. LRT = lumpectomy with radiation; LRT + TAM = lumpectomy with radiation and tamoxifen.