Posted on January 10, 2023

By Krystal Redman (KR), DrPH, MHA, (they/she), Executive Director

Clinical Updates: Impact of Race and Ethnicity on Recurrence Risk in Patients with Ductal Carcinoma in Situ Treated with Breast-Conserving Surgery

In the poster spotlight session titled Less is More: Minimizing Surgical Treatment in Patients with Early-Stage Breast Cancer, Natalia Polidorio, MD, PhD, Clinical Research Fellow of Breast Service with the Department of Surgery at Memorial Sloan Kettering Cancer Center, presented her research, Impact of Race and Ethnicity on Recurrence Risk in Patients with Ductal Carcinoma in Situ Treated with Breast-Conserving Surgery.

Dr. Polidorio began by offering some background on the study. In women diagnosed with invasive breast cancer, there are observed variations in clinical presentation, tumor biology, and survival based on race and ethnicity. However, the influence of race and ethnicity on clinical presentation and the risk of recurrence in women with ductal carcinoma in situ (DCIS) undergoing breast-conserving surgery (BCS) has not been thoroughly investigated. The study’s aim was to assess recurrence rates among women with DCIS across different racial and ethnic groups and to identify factors associated with recurrence.

Patients diagnosed with DCIS who underwent BCS between 1978 and 2016 at a medical institution were included in this study. The patients were categorized based on their self-reported race and ethnicity into groups: Asian, Hispanic, non-Hispanic Black (Black), and non-Hispanic white (white). Individuals with unspecified ethnicity were categorized based on race, while those lacking data for both race and ethnicity were excluded from the analysis. Comparative analysis of clinicopathologic characteristics, which are defined as those relating to both the signs and symptoms directly observable by a physician, and with the results of laboratory examination, was conducted across different racial and ethnic groups. 

It’s important for me to break down the results of this study, in order to determine whether this data offers any relevance to improving quality of life, extending overall survival, or contributes to the latest research advances for people living with breast cancer. 

The study analyzed 4,207 cases of DCIS treated with BCS and provided several key findings:

Demographic Characteristics

  • The study cohort included a minimally diverse representation of races and ethnicities, with 6% Asian, 9% Black, 5% Hispanic, and 80% white.
  • The median age of the participants was 57 years, and there were variations in the use of radiotherapy (RT) and endocrine therapy among different racial and ethnic groups.

Clinical and Treatment Differences

  • Black women with DCIS tended to be older, while Asian women were younger.
  • Black women were more likely to have a clinical presentation, and both Black and Hispanic women were more likely to require ≥3 excisions.
  • The use of radiotherapy was most common among Hispanic women.

Local Recurrence Rates

  • At a median follow-up of 8.8 years, 602 cases (14%) experienced local recurrence (LR), including 315 with DCIS and 284 with invasive recurrence.
  • The 10-year rate of local recurrence was 15%, and it was lower in those treated with radiotherapy compared to those without, despite the former having more high-risk characteristics.
  • Rates of local recurrence varied significantly by race and ethnicity, with the highest 10-year rate observed in Black women.

Risk of Local Recurrence

  • After adjusting for other factors in multivariable analysis, Black women had a higher risk of local recurrence compared to other racial groups.
  • Older age, radiologic presentation, margins ≥ 2 mm, the use of endocrine therapy, and the use of radiotherapy were associated with lower rates of local recurrence.

Implications for Overall Survival 

  • The study does not explicitly mention overall survival outcomes.
  • However, the higher rates of local recurrence, especially in Black women, indicate a need for thorough consideration of adjuvant therapy decisions to potentially improve overall outcomes.

In summary, addressing these disparities may contribute to better overall survival outcomes by optimizing the choice of adjuvant therapies based on individual risk profiles. The study highlights disparities in local recurrence rates among women with DCIS treated with breast-conserving surgery based on race and ethnicity. In particular, Black women exhibited a higher risk of local recurrence even after adjusting for other factors. The findings underscore the importance of considering demographic and clinical factors in the management of DCIS to tailor treatment approaches and improve outcomes.

Adjuvant therapy decisions in the context of cancer refer to the use of additional treatments after the primary treatment, such as: surgery, chemotherapy, radiation therapy, hormone therapy, etc., to reduce the risk of cancer recurrence. The goal of adjuvant therapy is to eliminate any remaining cancer cells that may not have been removed or targeted by the initial treatment. So, when discussing the root causes of breast cancer, the disparate impacts on Black, Indigenous, and People of Color (BIPOC) communities, social determinants of health, and inequities in health outcomes, we must also include conversations on de-escalated treatment regimens for BIPOC people who have a higher risk of cancer recurrence. Finally, considering the lack of ethnic diversity in this clinical study, before a strong recommendation is made to any community of people, we need more clinical trials with higher rates of engagement and representation of ethnically diverse communities.