Today’s newspaper headlines reported that “fewer women needing chemotherapy” and another said, “70% of breast cancer patients do not need chemotherapy”. This caused a lot of confusion. I was inundated with phone calls and my clinic was flooded with concerned patients and /or their relatives wanting to check whether they should continue chemotherapy.
Let’s understand the context clearly. Before the advent of genomic tests, we traditionally used tumour size, grade, lymph nodal status and hormone receptor status to decide the need for adjuvant chemotherapy for early breast cancer (stage 1, 2 a). With the advent of genomic tests (i.e. Oncotype Dx etc ), we were able to stratify the patients with early breast cancer into a low, intermediate and high-risk group. By risk, we refer to the possibility of developing a recurrence of the breast cancer. The high risk group would be recommended chemotherapy. The low risk group will not need chemotherapy as the potential risk of relapse is very negligible.
The grey area is the intermediate risk group. It is frustrating for patients and clinicians when a definite answer cannot be provided, that too after spending a lot of money on these tests. We ended up individualising again based on the traditional prognostic factors like age and tumour size.
The results of the tailorX study which was published a few days back addressed this group. Patients falling in the intermediate risk category were randomized to chemotherapy and no chemotherapy treatment arms and after 9 years of follow up the recurrence rates were analysed and presented on June 3rd, 2018. According to this study results, in a select group patients with receptor positive, node negative early breast cancer who fall in the intermediate category adjuvant chemotherapy will not add to benefit over hormonal therapy. Chemotherapy can be avoided in this group.
To stratify the risk, genomic tests like Oncotype DX (which was used in this study) will have to be done. The paraffin block of the tumour tissue is sent to the lab in USA (this test is currently done only in the USA) and it takes about 3 weeks to get the result. It costs roughly about 4000 USD (ie) 2.72 lakh Indian rupees.
A vast majority of our patients in our country are diagnosed at an advanced stage. The relapse rates are higher in advanced breast cancer and therefore chemotherapy is still a very essential component of the treatment protocol. Contrary to this, in the western world, the vast majority of breast cancers are diagnosed early. Genomic tests and selectively administering chemotherapy based on risk based on genomic tests are widely practiced. Sadly this cannot be applied to a great majority of our patients because of the advanced stage at presentation and the costs of these tests.
In addition to traditional prognostic factors like tumour size, grade, lymph nodal status we look at the estrogen receptor (ER), progesterone receptor (PR), Her2 and Ki 67 values. The ER, PR, Her2, and ki67 together are tested currently by immunohistochemistry. Together they could potentially closely reflect the Oncotype dx risk stratification. It could be the poor man’s alternative to Oncotype dx.
The challenges with IHC 4 tests is with the subjectivity of Ki 67 values. Less expensive test kits which have more objective Ki 67values could be the answer and these have to be validated in clinical trials with Oncotype dx.
Breast cancers are heterogeneous. The treatment is largely individualized and the one size fits all is probably not applicable anymore. But one has to be very cautious when reporting results of these studies in the print and visual News media. The headlines like” 70 % of breast cancer patients will not require chemotherapy” can lead to misunderstanding on the part of patients and there is a serious risk of patients skipping chemotherapy and dropping out of treatment and follow up which result in poor survival outcomes.
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