Do Young Women Have Worse Breast Cancer Outcomes? It Seems to Depend on the Cancer’s Characteristics

Save as Favorite
Sign in to receive recommendations (Learn more)

Breast cancer in women age 40 or younger isn’t common -- about 6% to 7% of all breast cancers in the United States are diagnosed in women in this age group. Still, breast cancer diagnosed in younger women is likely to be more aggressive or metastatic at diagnosis, and women in this age group have worse survival compared to older women.

Researchers wondered if these statistics were really true for all diagnosed younger women, or if outcomes varied based on the characteristics of the breast cancer.

A study suggests that younger women diagnosed with luminal A breast cancer have worse survival compared to older women diagnosed with the same subtype.

The research was published online on August 1, 2016 by the Journal of Clinical Oncology. Read the abstract of “Subtype-Dependent Relationship Between Young Age at Diagnosis and Breast Cancer Survival.”

Eric Winer, M.D., director of the breast oncology center at the Dana-Farber Cancer Institute and member of the Breastcancer.org Professional Advisory Board, is one of the study’s authors.

Luminal A and luminal B breast cancer are two of the four main molecular subtypes of breast cancer:

  • Luminal A breast cancer is hormone-receptor positive (estrogen-receptor and/or progesterone-receptor positive), HER2 negative, and has low levels of the protein Ki-67, which helps control how fast cancer cells grow.
  • Luminal B breast cancer is hormone-receptor positive (estrogen-receptor and/or progesterone-receptor positive), and either HER2 positive or HER2 negative with high levels of Ki-67.
  • Triple-negative/basal-like breast cancer is hormone-receptor negative (estrogen-receptor and progesterone-receptor negative) and HER2 negative.
  • HER2-enriched breast cancer is hormone-receptor negative (estrogen-receptor and progesterone-receptor negative) and HER2 positive.

In the study, the researchers looked at the records of 1,916 women age 40 or younger who were diagnosed with stage I to stage III breast cancer between 2000 and 2007 as well as 5,249 women who were age 51 to 60 when diagnosed with breast cancer and were treated at one of eight cancer centers around the United States. The researchers had about 6 years of follow up information on the women.

They compared the breast cancer outcomes of the younger women to the breast cancer outcomes of the older women.

The characteristics of the younger women:

  • 73.4% were white, 10.9% were Hispanic, 9.0% were black, and 5.1% were Asian
  • 26.7% were college graduates
  • 28.6% were diagnosed with stage I disease, 50.8% were diagnosed with stage II disease, and 20.7% were diagnosed with stage III disease

The characteristics of the older women:

  • 81.8% were white, 6.6% were Hispanic, 7.5% were black, and 2.7% were Asian
  • 19.3% were college graduates
  • 45.1% were diagnosed with stage I disease, 39.6% were diagnosed with stage II disease, and 15.3% were diagnosed with stage III disease

The researchers classified the breast cancers into the four main molecular subtypes. The numbers of younger women diagnosed with each subtype:

  • 510 (26.5%) were diagnosed with luminal A disease
  • 698 (36.4%) were diagnosed with luminal B disease
  • 189 (9.9%) were diagnosed with HER2-enriched disease
  • 478 (24.9%) were diagnosed with triple-negative disease
  • 41 (2.1%) had breast cancer that wasn’t classified

The numbers of older women diagnosed with each subtype:

  • 2,391 (45.6%) were diagnosed with luminal A disease
  • 1,428 (27.2%) were diagnosed with luminal B disease
  • 410 (7.8%) were diagnosed with HER2-enriched disease
  • 861 (16.4%) were diagnosed with triple-negative disease
  • 159 (3.0%) had breast cancer that wasn’t classified

Just under half the younger women were treated with chemotherapy and hormonal therapy after surgery:

  • 43.0% were treated with chemotherapy and hormonal therapy
  • 32.2% were treated with chemotherapy only
  • 5.6% were treated with hormonal therapy only
  • 7.5% were treated with chemotherapy, hormonal therapy, and Herceptin (chemical name: trastuzumab)
  • 0.10% were treated with Herceptin only
  • 5.5% were treated with chemotherapy and Herceptin
  • 6.1% of the younger women had missing treatment information

About a third of the older women were treated with chemotherapy and hormonal therapy after surgery:

  • 37.2% were treated with chemotherapy and hormonal therapy
  • 20.3% were treated with chemotherapy only
  • 24.7% were treated with hormonal therapy only
  • 3.8% were treated with chemotherapy, hormonal therapy, and Herceptin
  • 0% were treated with Herceptin only
  • 0.02% were treated with hormonal therapy and Herceptin
  • 4.0% were treated with chemotherapy and Herceptin
  • 9.9% of the older women had missing treatment information

The outcomes analysis showed that overall, women age 40 or younger when diagnosed were 30% more likely to die from breast cancer than women who were age 51 to 60 when diagnosed.

When the researchers looked at outcomes between younger and older women based on breast cancer subtypes, they found:

  • Women age 40 or younger diagnosed with luminal A disease had about twice the risk of dying from breast cancer compared to women age 51 to 60 with the same subtype.
  • Women age 40 or younger diagnosed with luminal B disease had a slightly higher risk of dying from breast cancer compared to women age 51 to 60 with the same subtype.
  • Women age 40 or younger diagnosed with triple-negative disease had about the same risk of dying from breast cancer as women age 51 to 60 with the same subtype.
  • Women age 40 or younger diagnosed with HER2-enriched disease had about the same risk of dying from breast cancer as women age 51 to 60 with the same subtype.

At first the results of this study may seem hard to understand. Because luminal A breast cancers tend to be slow-growing and less aggressive than the other subtypes, they are associated with the most favorable outcomes. Still, these favorable outcomes depend on the cancer’s responding well to hormonal therapy. Other research has shown that compared to older women, younger women are more likely to stop taking hormonal therapy early or never start taking it. This could be part of the reason why younger women diagnosed with luminal A breast cancer have less favorable outcomes than older women diagnosed with the same subtype. It could also be that luminal A cancers are more aggressive in younger women than luminal A cancers in older women.

“This paper helps us understand the importance of treatment adherence for women diagnosed with luminal A cancer,” said Marisa Weiss, M.D., Breastcancer.org founder and chief medical officer. “To take hormonal therapy for 10 years -- which may mean that younger women go into menopause early -- it’s a big commitment. Still, breast cancer is a serious disease and requires serious treatments. Treatment advances have helped many women live long, rich, fulfilling lives after being diagnosed. But the treatment has to be taken as prescribed to be effective.”

If you’re a younger woman who’s been diagnosed with hormone-receptor-positive breast cancer and will be taking hormonal therapy after surgery and other treatments, it’s very important that you take the medicine for as long as it’s prescribed. Hormone-receptor-positive breast cancer can come back and hormonal therapy after surgery reduces that risk -- you must remember that.

There are many different reasons why people may not follow their treatment plan as they should, including financial issues, side effects, and depression. If the cost of hormonal therapy is a concern for you, there are organizations that can help, including the assistance programs of many pharmaceutical companies and the National Cancer Institute. For more information, visit the Breastcancer.org Staying on Track With Treatment pages.



Mini 300x125 eoy appeal v2
Back to Top