From the Guidelines
Triple negative breast cancer is not the same as triple negative ductal carcinoma in situ (DCIS), as they represent different stages of disease with distinct treatment approaches and prognoses. The key difference lies in the invasive nature of triple negative breast cancer, where cancer cells have broken through the duct walls, potentially spreading to surrounding tissues and other parts of the body, whereas triple negative DCIS is a non-invasive condition confined within the milk ducts of the breast 1. This distinction is crucial because it affects treatment approaches and prognosis, with DCIS generally considered stage 0 breast cancer having excellent survival rates when properly treated, typically with surgery and sometimes radiation, in contrast to invasive triple negative breast cancer which requires more aggressive treatment, often including chemotherapy, and carries a higher risk of recurrence and poorer prognosis compared to other breast cancer subtypes 2.
Some key characteristics of triple negative breast cancer include a relatively poorer prognosis, with women experiencing the peak risk of recurrence within 3 years of diagnosis, and increased mortality rates for 5 years after diagnosis 2. Additionally, triple negative breast cancer has been associated with African-American race, deprivation status, younger age at diagnosis, more advanced disease stage, higher grade, high mitotic indices, family history of breast cancer, and BRCA1 mutations 2.
In terms of treatment, patients with triple-negative breast cancer may be offered the addition of immune checkpoint inhibitor to chemotherapy as first-line therapy, single-agent chemotherapy rather than combination chemotherapy, or treatment with sacituzumab govitecan, depending on the specific circumstances of their disease 1. However, the treatment of triple negative DCIS is generally more straightforward, involving surgery and sometimes radiation, with excellent survival rates when properly treated.
Overall, while both triple negative breast cancer and triple negative DCIS share the triple negative status, they are distinct conditions with different treatment approaches and prognoses, and should be managed accordingly.
From the Research
Definition of Triple Negative Breast Cancer
- Triple negative breast cancer (TNBC) is defined by the lack of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2) expression 3, 4, 5.
- TNBC accounts for 15% to 20% of all invasive breast carcinomas and is characterized by high rates of disease recurrence and worse survival 3.
Relationship between Triple Negative Breast Cancer and Ductal Carcinoma In Situ (DCIS)
- There is evidence to suggest that triple-negative DCIS is a rare entity, and that triple-negative invasive breast cancers often lack a DCIS precursor 6.
- A study found that the pooled distributions of tumor-type incidences differed between DCIS and invasive breast cancer, suggesting a strong selection pressure that reduces the number of triple-negative DCIS lesions at the time of breast tumor diagnosis 6.
- The model predicts that the shares of breast cancer tumor types in the modeled population (DCIS plus invasive BCs) are 39% for luminal A, 20% for luminal B, 11% for HER2 positive, and 30% for the triple-negative cancers 6.
Distinction between Triple Negative and Basal Breast Cancers
- Triple-negative breast cancer (TNBC) and basal-like breast cancer (BLBC) are often thought to be synonymous, but they represent different biologic phenomena 7.
- BLBC is a subtype of breast cancer characterized by a specific gene expression profile, while TNBC is defined by the lack of estrogen receptor, progesterone receptor, and HER2 expression 7.
Conclusion about Triple Negative DCIS
- Based on the available evidence, it appears that triple negative DCIS is not the same as triple negative breast cancer, as the former is a rare entity and the latter is a more common and aggressive form of breast cancer 6.