Chemo or no chemo for Stage 1

Hi Marie47:

An "equivocal" HER2 test result is not considered either positive or negative. In the case of an "equivocal" result by IHC or FISH, "reflex testing" (a further test) using the alternative method should be performed. For example, if equivocal by IHC, then a FISH test would be ordered.

What type of breast cancer is the 1.1 cm tumor? The most common type is invasive ductal carcinoma ("IDC").

If the results of further HER2 testing are clearly negative: For node-negative (N0), invasive ductal, lobular, mixed or metaplastic tumors that are hormone-receptor positive, HER2-negative, Tumor greater than > 0.5 cm in size, the next step might be a test such as the Oncotype test for invasive disease (more common in the US) or the MammaPrint test (currently more common in Europe).

For example, the Oncotype test for invasive disease measures the expression levels of 16 cancer-related genes (and 5 control genes) from the tumor sample, and computes an overall "Recurrence Score" from 0 to 100. In general, the Recurrence Score provides information about the risk of distant recurrence with tamoxifen alone or with tamoxifen plus chemotherapy. This information is used to inform decision-making about chemotherapy. Thus, chemotherapy may or may not be recommended, depending on the results of the test.

If the result of further HER2 testing are clearly positive: In the US, under treatment guidelines from the NCCN (version 2.2016), for node-negative (N0), invasive ductal, lobular, mixed or metaplastic tumors that are hormone-receptor positive, HER2-positive, and the Tumor size greater than >1 cm, a person is likely to receive a recommendation for adjuvant chemotherapy plus HER2-targeted therapy, followed by endocrine therapy (e.g, tamoxifen). Of course, the guidelines indicate what is done in the typical case and are not mandatory, so factors such as clinical and pathologic features of the tumor, age, and co-morbidities may be considered by your team in arriving at a recommendation.

Keep us posted.

BarredOwl

Hi Marie47:

By "onx", do you mean the OncotypeDX test for invasive disease?

Those who are hormone receptor positive, HER2-negative by standard pathology methods are "eligible" for the OncotypeDX test for invasive disease:

Eligibility: http://breast-cancer.oncotypedx.com/en-US/Professional-Invasive/OncotypeDXBreastCancerAssay/PatientEligibility.aspx

"Eligibility" of a biomarker test like this one is a reflection of the scope of "validation" of a test (clinical evidence supporting the prognostic and/or predictive capabilities of the test in certain kinds of patients). The OnctoypeDX test and multi-gene Recurrence Score are validated for HER2-negative patients. In such a node-negative patient ("N0"), the multi-gene Recurrence Score is associated with an estimate of "10-year risk of distant recurrence after 5-years of tamoxifen", and is used for informing decisions about chemotherapy (endocrine therapy alone versus endocrine therapy plus chemotherapy). The information provided by the multi-gene Recurrence Score does not address the use of HER2-targeted agents (e.g., trastuzumab).

IHC and ISH are the preferred validated methods for determining HER2 status. While the Oncotype report includes a "quantitative single-gene report for HER2", the FDA has expressed concerns about false-negative results with this test, raising the possibility of under-treatment (failure to provide trastuzumab). There might be specialized cases where it is appropriate to consider the individual oncotype HER2 score, but such a specialized case likely warrants a second opinion. Thus, if the single-gene HER2 information from the Oncotype report is used in your case, please consider seeking a second opinion about such use.

In any case, perhaps you could seek a second opinion, including an expert pathology review of all HER2 testing, and advice re whether any further testing may be indicated by another method and/or different region of the surgical samples.

You may also wish to seek a second opinion from a medical oncologist about the relevance of the OncotypeDX test multi-gene Recurrence Score to your situation and the estimated benefit of adding chemotherapy to endocrine therapy. On the other hand, if based on HER2 status (positive or equivocal after extensive testing), you are offered chemotherapy plus HER2-targeted therapy, such as paclitaxel plus trastuzumab, you can seek more discussion of risk / benefit.

If you are near an NCI-designated cancer center, that may be a good choice for a second opinion:

http://www.cancer.gov/research/nci-role/cancer-centers/find

Some places may provide remote expert pathology review (e.g., Johns Hopkins).

I have no medical training, so please confirm all information above with your team to ensure you receive current, accurate, case-specific expert professional advice on these questions.

BarredOwl