Can I safely skip aggressive breast cancer treatment?

After being diagnosed with breast cancer, a woman faces a mountain of choices about treatment.

Lumpectomy or mastectomy? Reconstruction or flat? Chemotherapy? Radiation? Estrogen-blocking medicine?

Wouldn’t it be great to have our own personal Minority Report? A service that could predict cancer that will spread and kill (rather than people who will commit a crime in the future).

Breast cancer has historically been assigned a risk assessment — a stage — based on tumor size; whether or not lymph nodes contain cancer; and whether the cancer has metastasized (spread) to other parts of the body.

The cancer has been historically categorized by its point of origin, such as ductal or lobular, rather than its behavior or genomic makeup. But it turns out that its genomic characteristics may be as much an indicator of risk as size or lymph node involvement. Researchers have developed tests that predict how cancer might behave and respond to treatment.

A genomic test isn’t the same thing as a genetic test. Genomic tests analyze a sample of your cancer tumor to see how likely it is to grow and spread. Genetic tests, on the other hand, assess a sample of your DNA to see if you have an abnormal mutation in a gene that is linked to a higher risk of breast cancer, such as BCRA.

This predictive model is important for more than peace of mind.  Dr. Laura Esserman, University of California, San Francisco, told NPR in June that about 20-25% of breast cancer diagnosed today may not require treatment post-surgery because it is “ultralow-risk.”

“We can tell [these] women that they are highly unlikely to die of their cancers and do not need aggressive treatment,” Esserman says. “This is an important step forward” for [personalized medicine].

Dr. Esserman was the lead researcher on a US-Swedish investigation of MammaPrint.

Each of these tests is designed for early stage breast cancer; most are predictive for cancers that are contained in the breast (have not spread to lymph nodes). This is a breast cancer Minority Report in the making. In the meantime, they help make decisions about chemotherapy or the length of hormonal therapy.

Breast Cancer Index

The Breast Cancer Index can help women and their doctors decide if extending hormonal therapy from 5 to 10 years would be beneficial. The index is based on analysis of five genes.

For patients with early stage hormone-receptor-positive breast cancer that is node-negative
Company: bioTheranostics

EndoPredict

EndoPredict categorizes the cancer as having either a high risk or low risk of distant recurrence (metastasis) 10 years after diagnosis. It examines 12 genes, which it combines with tumor size and lymph node status to create an individualized risk score.

For patients with hormone-receptor-positive, HER2-negative breast cancer with up to three lymph nodes involved.
Company: Sividon Diagnostics

MammaPrint

MammaPrint analyzes 70 genes to assess the risk of a cancer recurrence. MammaPrint was the first in vitro diagnostic multivariate index assay (IVDMIA) to be cleared by the FDA (2007).

For patients with early stage hormone-receptor-positive or hormone-receptor-negative breast cancer with up to three lymph nodes involved.
Company: Agendia

Mammostrat

Mammostrat assesses five genes, thought to influence whether the breast cancer tumor will metastasize, to determine risk of recurrence. It’s relatively new; the company received patents in the US and Europe in 2010.

For patients with early stage hormone-receptor-positive breast cancer that is node-negative.
Company: Clarient Diagnostic Services

Oncotype DX

Oncotype DX examines 21 genes and then assigns a numerical score to help predict the chance of recurrence of early stage cancer or DCIA; the results range from 0 to 100.

For patients with hormone-receptor-positive, HER2-negative breast cancer that is node-negative or node-positive (stage I, II, or IIIa)
Company: Genomic Health

 

 

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