21-Gene Recurrence Score Used By Oncologists Can Also Be Used For Radiation Decision-Making
Source: Thailand Medical News Jan 10, 2020 4 years, 10 months, 4 days, 6 hours, 55 minutes ago
A recent research shows that a test oncologists commonly used to guide chemotherapy treatment for post-
breast cancer surgery patients may also help them decide whether
radiation therapy may be of benefit.
Commonly known as the
21-gene recurrence score, the test is a personalized analysis of the activity of 21 genes found in a patient's
breast tumor tissue. The score can be used to predict whether, after undergoing surgery, that patient's
breast cancer is likely to return in another part of their body, like the bones or lungs, and whether that patient will likely benefit from
chemotherapy treatment.
Research findings suggest patients with an intermediate or high
21-gene recurrence score are more likely to see their
cancer return to the
breast and nearby lymph nodes and, thus, could benefit from
radiation. Findings appear today in
JAMA Oncology. The study was conducted by the SWOG
Cancer Research Network, a
cancer clinical trials network funded by the National
Cancer Institute (NCI), part of the National Institutes of Health, and part of the oldest and largest publicly funded research network in the nation.
The new Canadian
Cancer Trials Group, with co-sponsorship by the NCI, is enrolling patients on a trial called
TAILOR RT, which will confirm whether the
recurrence score,all by itself can identify low risk node positive patients who do not need
radiation. Because randomized trials represent the gold standard in clinical research,
TAILOR RT results could change the standard of
cancer care. Until that data is in, the SWOG findings provide evidence that the
recurrence score can be an effective, additional tool along with tumor size or stage that physicians can use to determine whether to recommend
radiation therapy, particularly for patients whose
cancer presentation makes the need for
radiation uncertain.
Dr Wendy Woodward, MD, Ph.D., lead investigator of the SWOG study and chief of the clinical breast radiotherapy service at the University of Texas M.D. Anderson Cancer Center told
Thailand Medical News, "For a decade,
radiation oncologists have been banging on the doors of precision medicine, looking for genomic tools they can use to personalize treatment for their patients.
Radiation oncologists want these tools because they can help their patients.
Radiation treatment can help wipe out local disease, saving or lengthening a patient's life. And omitting
radiation treatment could spare other patients pain, time, and cost."
The mentioned
21-gene recurrence score test is sold as the Oncotype DX Breast
Recurrence Score
and was developed by the California-based company Genomic Health, Inc. In multiple research studies, the test has been proven to predict the likelihood of disease recurrence and
chemotherapy benefit in patients with invasive, early-stage
breast cancer.
The oncology test made international headlines in June 2018 when the results of the Trial Assigning Individualized Options for Treatment, or
TAILORx, were released at the annual meeting of the American Society of Clinical Oncology. Results from
TAILORx, the largest randomized post-surgery
breast cancer trial ever mounted, showed that the test could predict who would, and would not, benefit from
chemotherapy.
Dr Woodward and her team wanted to see if the
21-gene recurrence score could also be useful in predicting the local
breast cancer recurrence that
radiation can prevent.
Radiation is much more targeted than
chemotherapy, focusing on specific areas in and around the
breast.
Dr Woodward was particularly interested in how
recurrence scores might help add to the clinical tools that currently guide radiation for patients especially when the need isn't clear.
Breast cancer patients who have undergone mastectomy, have low-risk clinical factors, and cancer-free lymph nodes often do not require
radiation treatment after their
cancer surgery. However, those with large tumors and
cancer in four or more lymph nodes almost definitely get radiation. But what about patients with a more ambiguous presentation say, a smaller tumor and one to three
cancer-positive lymph nodes? Can scores help safely guide radiation decisions?
To investigate, Dr Woodward and her team dove into data generated by S8814, a long-closed SWOG trial that compared post-surgery treatments in post-menopausal women with
breast cancer. In this randomized trial, postmenopausal women with node-positive
breast cancer were randomly assigned to one of three treatments. Physicians recommended
radiation therapy based on clinical factors, such as tumor size and the number of lymph nodes that contain
cancer.
As a part of S8814, 367 patients took the
21-gene recurrence score test. Dr Woodward and her team reviewed all these records to see which patients had
radiation therapy and which had what's known as locoregional recurrence (LRR), when
cancer returns after treatment close to the site of the original tumor, in this case, the
breast, chest wall, or lymph nodes.
After winnowing out certain patients, the SWOG team wound up with a pool of 316 patient records. They logged every patient's
recurrence score, and also whether and when LRR occurred. In all, after a median of eight years of follow-up, 34 patients went on to have an LRR event—27 with intermediate or high
recurrence scores and seven with low
recurrence scores. Regardless of other factors, such as number of
cancer-positive lymph nodes, the
recurrence score proved to be an independent predictor for LRR.
Dr Woodward added, "We believe these data support using
recurrence scores along with standard clinical factors like age or tumor size to determine risk of recurrence and
radiation therapy decisions for patients. Our findings are clearly limited, as we had some small patient numbers and looked at data retrospectively. But these results provide additional evidence of the value of this test in node positive patients. And they suggest it might be possible to skip
radiation in patients with low
recurrence scores and one to three
cancer-positive nodes, a question now being rigorously tested in
TAILOR RT. There are large clinical trials going on looking at
radiation care for
breast cancer patients, like
TAILOR RT, and I encourage people to enroll. The more data we have, the more we'll know how to use this new precision medicine tool."
Reference : Wendy A. Woodward et al, Association Between 21-Gene Assay Recurrence Score and Locoregional Recurrence Rates in Patients With Node-Positive Breast Cancer, JAMA Oncology (2020). DOI: 10.1001/jamaoncol.2019.5559
