Yesterday I gave you the opportunity to have some elementary education about breast cancer. Today we are back to the advanced level with a study about the impact of the Oncotype DX test/scores and decisions re chemotherapy. Some of you may not be familiar with this test which has been around for about eight years. When I was diagnosed with a second breast cancer in 1995, it was quite new and not so much yet used. My insurance company would not even pay for it (although that changed shortly thereafter--unfortunately after I had written a check to cover the cost). Since my medical situation at the time had some gray areas and difficult to assess features, this seemed a very good way to acquire more information about my risk for recurrence. The score came back in the intermmediate range, and I opted for chemotherapy.
First, from BreastCancer.org, here is basic information about what this test is and does and a link to read more about it:
The Oncotype DX test is a genomic test that analyzes the activity of a group of genes that can affect how a cancer is likely to behave and respond to treatment. The Oncotype DX is used in two ways:
- To help doctors figure out a woman's risk of early-stage, estrogen-receptor-positive breast cancer coming back (recurrence), as well as how likely she is to benefit from chemotherapy after breast cancer surgery.
- To help doctors figure out a woman's risk of DCIS (ductal carcinoma in situ) coming back (recurrence) and/or the risk of a new invasive cancer developing in the same breast, as well as how likely she is to benefit from radiation therapy after DCIS surgery.
The results of the Oncotype DX test, combined with other features of the cancer, can help you make a more informed decision about whether or not to have chemotherapy to treat early-stage hormone-receptor-positive breast cancer or radiation therapy to treat DCIS.
Below, you can read more about the following topics:
- Who is eligible for the Oncotype DX test?
- How does Oncotype DX work?
- Interpreting the results
- And should you be interested in a bit more about the value of this test, here is an interesting article from Breast Cancer Research and Treatment about its use seeming to reduce the use of adjuvant chemotherapy. This article suggests that there is not a straightforward explanation for this, but speculates and gives a lot of data. Here is the abstact and then a link:
- Why does Oncotype DX recurrence score reduce adjuvant chemotherapy use?
- Jeffrey G. Schneider • Danny N. Khalil
Abstract The Oncotype DX recurrence score (RS) reduces breast cancer adjuvant treatment utilization, but the reasons for this effect are not straightforward. We per- formed a retrospective chart review of 89 consecutive node-negative breast cancer patients for whom RS was ordered to facilitate adjuvant treatment decisions. By sub- tracting the relapse rate predicted by RS from that calcu- lated using the Adjuvant! Online (AOL) web-based instrument, a ''prognostic delta'' (PD) was determined, reflecting the difference between prognoses predicted by these two indices. Clinician interviews were conducted to evaluate the actual effect of RS on treatment decisions and its relation to PD. Adjuvant chemotherapy use decreased from 61 to 26 % as a consequence of RS results (p \ 0.0001). In multivariate analysis, RS was the only factor significantly associated with the final adjuvant treatment choice. Surprisingly, RS caused chemotherapy to be withheld even when PD was negative (i.e., cases in which RS predicted a less favorable outcome than AOL). The prognostic and chemotherapy predictive utilities of the RS do not fully account for its effect in reducing adjuvant chemotherapy use. Further studies are required to more fully elucidate other factors that may be responsible for this effect, including the possibility of unintended influence.