Vasily Giannakeas1,2, Victoria Sopik1,3, Steven A Narod4,5,6. 1. Women's College Research Institute, 76 Grenville Street, Toronto, ON, M5S 1B1, Canada. 2. Dalla Lana School of Public Health, University of Toronto, Toronto, Canada. 3. Institute of Medical Science, University of Toronto, Toronto, Canada. 4. Women's College Research Institute, 76 Grenville Street, Toronto, ON, M5S 1B1, Canada. steven.narod@wchospital.ca. 5. Institute of Medical Science, University of Toronto, Toronto, Canada. steven.narod@wchospital.ca. 6. Dalla Lana School of Public Health, University of Toronto, Toronto, Canada. steven.narod@wchospital.ca.
Abstract
BACKGROUND: Approximately 1% of patients with ductal carcinoma in situ (DCIS) will die of breast cancer within 10 years. Women who develop an invasive breast cancer after DCIS have a much greater risk of dying than those who do not and it is often stated that these deaths are a consequence of metastases from the invasive in-breast recurrence. This progression is the result of a two-step process: first local invasive recurrence and then spread beyond the breast. A large proportion of women who die of DCIS have no record of invasive recurrence. We used SEER data and a simulation approach to test whether the actual mortality data are consistent with the two-step model. METHODS: First, we constructed Kaplan-Meier mortality curves for all patients with pure DCIS and with small node-negative invasive breast cancers in the Surveillance, Epidemiology and End Results (SEER) registries database (1998-2014). We then constructed, through simulation, theoretical breast cancer mortality curves. To model the two-step scenario, we applied the annual incidence rates of incident invasive cancer following DCIS and of death from invasive cancer after DCIS to a theoretical cohort of 100,000 women. RESULTS: The observed 15-year breast cancer-specific mortality rate for patients with pure DCIS in the SEER database was 2.0%. The expected mortality for DCIS patients (assuming a two-step process) was only 1.1% at 15 years. Assuming the mortality rates following DCIS were one-half of those observed for patients with small invasive breast cancers, the expected mortality at 15 years post-DCIS was 2.1%. CONCLUSIONS: In the SEER database, we observed far more deaths from DCIS than would be expected under a model where all deaths from breast cancer occur amongst women who experience an invasive local recurrence. This lends support to the hypothesis that DCIS mortality is not restricted to those women who experience an in-breast invasive cancer and that DCIS has properties similar to small invasive breast cancers.
BACKGROUND: Approximately 1% of patients with ductal carcinoma in situ (DCIS) will die of breast cancer within 10 years. Women who develop an invasive breast cancer after DCIS have a much greater risk of dying than those who do not and it is often stated that these deaths are a consequence of metastases from the invasive in-breast recurrence. This progression is the result of a two-step process: first local invasive recurrence and then spread beyond the breast. A large proportion of women who die of DCIS have no record of invasive recurrence. We used SEER data and a simulation approach to test whether the actual mortality data are consistent with the two-step model. METHODS: First, we constructed Kaplan-Meier mortality curves for all patients with pure DCIS and with small node-negative invasive breast cancers in the Surveillance, Epidemiology and End Results (SEER) registries database (1998-2014). We then constructed, through simulation, theoretical breast cancer mortality curves. To model the two-step scenario, we applied the annual incidence rates of incident invasive cancer following DCIS and of death from invasive cancer after DCIS to a theoretical cohort of 100,000 women. RESULTS: The observed 15-year breast cancer-specific mortality rate for patients with pure DCIS in the SEER database was 2.0%. The expected mortality for DCIS patients (assuming a two-step process) was only 1.1% at 15 years. Assuming the mortality rates following DCIS were one-half of those observed for patients with small invasive breast cancers, the expected mortality at 15 years post-DCIS was 2.1%. CONCLUSIONS: In the SEER database, we observed far more deaths from DCIS than would be expected under a model where all deaths from breast cancer occur amongst women who experience an invasive local recurrence. This lends support to the hypothesis that DCIS mortality is not restricted to those women who experience an in-breast invasive cancer and that DCIS has properties similar to small invasive breast cancers.
Entities:
Keywords:
Breast cancer; DCIS; Mortality; Recurrence
Authors: Olivier Loudig; Megan I Mitchell; Iddo Z Ben-Dov; Christina Liu; Susan Fineberg Journal: Breast Cancer Res Date: 2022-09-12 Impact factor: 8.408