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Most Women with Early-Stage Breast Cancer Don’t Need Chemo

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Women discussing cancer treatment options

Credit: National Cancer Institute, NIH

In the last few days, you may have heard that there’s been a significant development in the management of breast cancer. So here’s the NIH Director’s blog description of what’s happened. Each year, as many as 135,000 American women who’ve undergone surgery for the most common form of early-stage breast cancer face a difficult decision: whether or not to undergo chemotherapy. Genetic testing of tumor tissue has helped to inform some of these decisions, with women whose tumors score high on the breast cancer recurrence scale likely to benefit from chemo, and those with low-scoring tumors able to skip the cost and potentially serious side effects. But there’s been a catch: most tumors score somewhere in the middle, leaving women and their doctors uncertain about what to do.

Now, thanks to the long-awaited results of a large, NIH-funded clinical trial, we finally have an answer. About 70 percent of women with hormone receptor (HR)-positive, HER2-negative, axillary lymph node-negative breast cancer—including those with mid-range scores on the cancer recurrence scale—do not benefit from chemotherapy [1]. These findings promise to spare a great many women with breast cancer from unnecessary exposure to costly and potentially toxic chemotherapy.

More than a decade ago, a research team, led by Joseph Sparano at New York’s Albert Einstein Cancer Center and Montefiore Health System, launched the ambitious Trial Assigning Individualized Options for Treatment, or TAILORx, which involved more than 10,000 women who’d undergone surgery for early-stage breast cancer. Their goal: to determine if chemo benefits women whose tumors have mid-range scores on the Oncotype DX Breast Cancer Assay, a widely used test that assesses the activity of 21 genes associated with breast cancer recurrence.

Previous research had shown that for tumors with a score of 10 or less, cancer is unlikely to recur within 10 years whether or not a woman undergoes chemo. It was also known that scores over 26 are associated with a high risk of cancer recurrence, and a good chance of benefiting from chemotherapy. But most tumors receive a mid-range score, from 11 to 25.

In findings presented at the 2018 American Society of Clinical Oncology meeting and published in The New England Journal of Medicine, the researchers reported that 69 percent of TAILORx participants (more than 6,700 women) had tumors that received a mid-range score. These women were randomly assigned to receive either the standard, post-surgical hormone therapy or the hormone therapy plus chemo.

The results were quite clear. Most women with mid-range scores did just as well with hormone therapy alone as those who got hormone therapy plus chemo. That is, their cancers were no more likely to spread. Overall, both groups had a 98 percent chance of survival at five years and 94 percent at nine years.

The researchers did identify one important exception. There was a small benefit from chemo in the subset of women who were 50 or younger at the time of diagnosis and who had recurrence scores from 16 to 25. This group accounts for about 14 percent of women with the common form of early-stage breast cancer.

The new findings suggest that at least 70 percent of women with HR-positive, HER2-negative, axillary lymph node-negative breast cancer—those with low scores and most of those with mid-range scores—can safely avoid chemotherapy. The remaining 30 percent of women, including all with scores of 26 or greater and younger women with scores of 16 or greater, should still consider chemo to reduce the risk of cancer recurrence.

Chemotherapy use for women with early-stage breast cancer had been declining in recent years due to more widespread use of the 21-gene test. With this new evidence, even more women can be spared.

Ongoing clinical trials are also exploring the usefulness of this test for women whose breast cancer has spread to the lymph nodes in the underarm. Researchers are also evaluating the usefulness of another test that surveys a panel of 50 genes. So, as NIH-funded research continues to make progress against breast cancer and many other types of cancer, one of our hopes is to bring greater precision and clarity to the tough treatment decisions that often face patients and their loved ones.

References:

[1] Adjuvant Chemotherapy Guided by a 21-Gene Expression Assay in Breast Cancer. Sparano JA, Gray RJ, Makower DF, Pritchard KI, Albain KS, Hayes DF, Geyer CE Jr, Dees EC, Goetz MP, Olson JA Jr, Lively T, Badve SS, Saphner TJ, Wagner LI, Whelan TJ, Ellis MJ, Paik S, Wood WC, Ravdin PM, Keane MM, Gomez Moreno HL, Reddy PS, Goggins TF, Mayer IA, Brufsky AM, Toppmeyer DL, Kaklamani VG, Berenberg JL, Abrams J, Sledge GW Jr. N Engl J Med. 2018 Jun 3. doi: 10.1056/NEJMoa1804710.

Links:

Breast Cancer (National Cancer Institute/NIH)

Joseph Sparano (Albert Einstein College of Medicine, New York)

The TAILORx Breast Cancer Trial (NCI)

NIH Support: National Cancer Institute

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