MODELING THE EFFECTIVENESS OF INITIAL MANAGEMENT STRATEGIES FOR DUCTAL CARCINOMA IN SITU

Purpose: The high prevalence of ductal carcinoma in situ (DCIS) and the marked variability in patterns of care highlight the need for comparative effectiveness research on the management of this condition. This study aimed to quantify the tradeoffs of alternative management strategies for DCIS with respect to disease outcomes and breast preservation.

Method: We developed a disease simulation model integrating data from randomized and retrospective trials in order to simulate the clinical events following six initial management strategies (lumpectomy alone, lumpectomy with radiation, lumpectomy with radiation and tamoxifen, lumpectomy with tamoxifen, and mastectomy with or without breast reconstruction) for women with newly diagnosed DCIS. We used the model to project a number of long-term outcomes including disease-free survival, invasive disease-free survival, overall survival, breast and breast-contour preservation, and death from breast cancer. 

Result: In a cohort of 1 million simulated women aged 45 years at diagnosis, the use of radiation therapy and tamoxifen, mastectomy alone and mastectomy with reconstruction, were associated with small improvements in overall survival relative to lumpectomy alone, providing an additional 10-11 months spent alive per patient. Adding radiation therapy to lumpectomy demonstrated even smaller improvements in overall survival (only increasing survival by 6 months) and compromises breast-preservation outcomes (0.843 versus 0.781 likelihood of breast preservation). This decrement in breast preservation with radiation therapy was mitigated with the addition of tamoxifen (0.846). Our findings also indicate that the benefits of lumpectomy with radiation and tamoxifen increase with increasing risk of recurrence and when using age-specific recurrence rates. 

Conclusion: The delineation of personalized outcomes for each of the DCIS treatment options will help patients understand the options and implications of their treatment choice, so that treatment decisions may reflect their own personal values and help improve the quality of care for patients with DCIS.