Risk of Recurrence for ER Positive Breast Cancer
Recently, a woman with ER positive breast cancer called us for advice. She had recently been diagnosed with T1 stage cancer and had no lymph nodes involved.
She had sought multiple opinions regarding radiation therapy and had received conflicting advice, with some doctors saying yes and others saying no.
Furthermore, she wanted to know what her risk of recurrence was. Since this is an important question that many women will need to consider, the following is an overview of our conversation.
We shared the risks of recurrence with her. Based on a recent meta-analysis of 88 clinical trials involving 62,923 women with ER positive breast cancer who were disease-free after five years of adjuvant endocrine therapy.
http://www.nejm.org/doi/full/10.1056/NEJMoa1701830
The risks of recurrence are as follows.
20-year risks of distant recurrence was:
- 22% in women with no positive nodes
- 31% in those with one to three positive nodes
- 52% in those with four to nine positive nodes
Among women with T1 disease, the 20-year of distant recurrence was:
- 13% with no nodal involvement
- 20% with one to three nodes involved
- 34% with four to nine nodes involved
Among women with T2 disease, the 20-year of distant recurrence was:
- 19% with no nodal involvement
- 26% with one to three involved nodes
- 41% with four to nine involved nodes
The woman happily thanked us and stated that since she was in excellent health and took care of herself, her chances of recurrence were very low and that she would skip the dangerous radiation therapy.
HOWEVER, our conversation was not over.
Firstly, we explained to her that the recurrence data above was specific for women that were CANCER FREE after five years of endocrine therapy. She had yet to achieve that.
Secondly, we explained that sentinel lymph node biopsies are used because they are the lymph nodes that directly drain the region of the tumour, and the most likely spot for tumours to metastasize to.
However, tumours can also metastasize via blood, and directly through tissue.
Since she had not yet had a PET/CT, we could not assure her that she did not have undetected tumours elsewhere in the body.
Read more about PET/CT here: https://www.ctoam.com/services/testing/imaging/pet-ct-scan/
Thirdly, we explained to her that while the above study addressed the pathology of the tumours, it did NOT consider the molecular features and biology of the tumour.In fact, the molecular features (genetic mutations that drive the growth of the tumours) are the MOST important consideration.
A recent study looked at a small panel of molecular features. A subset analysis of the MINDACT trial shows that oncologists may be undertreating women with small (< 1 cm) node-negative breast tumours. These tumour types are clinically considered to be low risk, but can be genomically high risk.
In this study, about one in four women with small node-negative breast tumours smaller than 1cm turned out to have tumours with high genomic risk that are biologically aggressive.
This may partially explain the new data that women with T1 breast cancers and no involved lymph nodes have better long term survival with adjuvant (post-surgery) radiation therapy.
Importantly, the molecular test in the above study was the Mamaprint, which only looks at 70 genes.
Traditionally, node-negative small breast cancers have been considered low-risk, for which adjuvant treatment is unnecessary.
However, recent advances in cancer biology and tumour DNA sequencing have shown that while tumour burden is still independently prognostic, tumour biology is key for outcome.
We finished our conversation with the advice that she:
1. Get a PET-CT to ensure she did not have distant metastasis that could be dealt with at an early and more treatable stage.
2. Get a Foundation One tumour DNA sequencing assay to ensure that:
a) her cancer was indeed ER positive and not a variant of triple negative breast cancer that happened to have ER positivity;
b) her cancer was not an aggressive subtype of ER positive breast cancer;
c) she knew of any mutations that could reduce or increase the efficacy of any chemotherapy drugs;
(d) she knew of any mutations that could provide options for targeted drugs or immunotherapy.
If you’d like a FREE consultation to discuss your best testing and treatment options, call or email CTOAM today. Talk to an oncogenomics specialist about your unique case to get expert insight on your best choices moving forward.
Learn more about how personalized cancer care can increase your chances of survival, extend life, and improve the quality of your life. Visit our comprehensive website at www.ctoam.com
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