Overall survival benefits of six management strategies for ductal carcinoma in situ (DCIS) are within 1 year of each other, according to a disease simulation model integrating empirical data from published literature and quantifying the tradeoffs among the different management strategies with respect to disease outcomes and breast preservation.
The model simulates the clinical events for women with newly diagnosed DCIS after these six treatments: lumpectomy alone, lumpectomy with radiation, lumpectomy with radiation and tamoxifen, lumpectomy with tamoxifen, and mastectomy with and without breast reconstruction.
“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,” the investigators reported in the Journal of the National Cancer Institute. “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).”
Consistent with Previous Evidence
The results were more pronounced for disease-free survival. Compared with lumpectomy alone, mastectomy yielded an additional 9.1 disease-free years (either from DCIS or invasive cancer). “Both mastectomy and lumpectomy with radiation and tamoxifen yielded the greatest invasive disease-free survival, providing an additional 5 years without invasive breast cancer compared with lumpectomy,” the researchers wrote.
The authors noted that their finding that the magnitude of overall survival benefits is within year is “consistent with the lack of difference observed in the randomized trials of radiation for DCIS and with prior DCIS modeling efforts. The magnitude of benefit is a critical factor in determining which treatment choice is appropriate for an individual patient. However, this should be weighed against the consequences of treatment in terms of breast preservation,” the authors added.
“Population-based analyses reveal large regional variation in treatment of DCIS,” the researchers noted in their conclusion. “This type of variation as opposed to selection of treatment according to patient preference is a marker of poor quality of care. 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,” they wrote.
Most Important Finding
“Perhaps the greatest contribution of the study is its finding that survival after mastectomy is similar to that after lumpectomy, radiation, and tamoxifen for all three patient ages” (45, 60, and 70 years old). This opinion was voiced in an accompanying editorial that noted, “A randomized trial of mastectomy versus breast conservation for DCIS is extremely unlikely to be feasible. Therefore, it is useful to be able to refer to these model results to reassure patients that they do not have to sacrifice the native breast to maximize survival.”
If the model developers truly want to realize their goal of having the model used as an aid in patient decision-making, “their next step should be to develop a user-friendly decision aid incorporating the findings of their model,” the editorial continued. “As clinicians, where we will find these results most useful is in counseling patients who believe that mastectomy is necessary to maximize survival. After many years of decreasing, some evidence suggests that mastectomy rates have again begun to rise. The current study may help to stem this concerning tide by providing reassuring evidence of the safety of breast conservation for patients with DCIS.” ■