News > Radiation may not be needed for some early-stage breast cancers

Radiation may not be needed for some early-stage breast cancers

The LUMINA clinical trial showed people with some low-risk, hormone receptor-positive breast cancers had low rates of recurrence with hormonal therapy alone


Hormonal therapy alone following surgery may be enough to prevent local recurrence in some people with early-stage hormone receptor-positive breast cancer. Research presented on June 7, 2022, at the annual meeting of the American Society of Clinical Oncology may support changing the treatment guidelines for certain breast cancers to reflect the findings of this study.


Treatment for early-stage breast cancer continues to change over time. In the past, doctors treated all breast cancers aggressively, using every therapy at their disposal. The impact on quality of life could be substantial, as people spent more months in treatment, and each treatment brought its own side effects. 

Today, more sensitive screening means more breast cancers are diagnosed very early. Surgery has also improved, as surgical oncologists use new techniques to see and remove the cancer. Drug and radiation therapies are more precise and tailored to the individual’s cancer. Yet, doctors still are mostly unable to predict which breast cancers will return.

Ongoing studies try to answer this question – looking for markers of cancers that are more or less likely to return. The goal is to avoid overtreatment – to determine which therapies are truly needed to complete treatment and prevent the cancer from coming back. 

Radiation is often effective but also can be costly and challenging because of the number of treatments. It can cause side effects such as fatigue, skin irritation and redness, and pain. It is often used with hormonal therapy, which is also highly effective in preventing recurrence in low-risk hormone receptor-positive, HER2-negative breast cancers.


Based in Canada, the LUMINA clinical trial sought to find out if some people with early-stage breast cancers could be spared radiation therapy. It was a carefully controlled, prospective cohort study, which in this case followed a group of people over time to see whether there were differences in their breast cancer outcomes. The study investigators focused on people with the Luminal A subtype of breast cancers, which past research shows has a low risk for local recurrence (coming back in the same area).

In this trial, Luminal A breast cancers were defined as testing positive for both estrogen and progesterone receptors and negative for HER2 receptors, and having a Ki-67 score of less than or equal to 13.25%. Ki-67 is a protein; a lower Ki-67 score means that breast cancer is not growing as quickly and is less likely to come back after treatment.

The study included 500 women ages 55 and older. They all had Luminal A, HR-positive, HER2-negative early-stage ductal breast cancer. Staging was determined by the TNM Staging System. Study participants had very small tumors (T1) and no cancer in the lymph nodes (N0). They all underwent lumpectomy followed by hormonal therapy for 5 years.

Trial staff followed participants for 5 years to see if their cancers returned. Participants had mammograms every 6 months for the first 2 years, and then annually.

The results fell far within the goals of the study. Only 12 people in the study had breast cancer return, 10 of which were local recurrences in the same area. As a result of the study design and the findings, some physicians at the meeting felt this information could immediately be used to guide clinical practice.

What this means for you

The findings from this study could alter the treatment guidelines for a subgroup of people with early-stage hormone receptor-positive, HER2-negative breast cancer. The research team estimates that this change could affect the breast cancer treatment of between 30,000 and 40,000 people in North America each year.

If you recently learned you or someone you care about has early-stage, hormone receptor-positive, HER2-negative breast cancer, talk with your oncologist about your treatment plan. If they recommend radiation, ask if they have heard about the recent findings from the LUMINA study. Do these findings apply to your situation?

It’s worth noting that all participants in this study were women. The median age of participants was 67 (half were younger, half were older), so the findings are unlikely to influence treatment for premenopausal women. These results may not be relevant to men with breast cancer, transgender men, and non-binary individuals.


Related resources

Intraoperative radiation therapy (IORT) breast cancer treatment

01/14/22 | BY: Neil K. Taunk

Intraoperative radiation therapy, or IORT, is a type of radiation therapy given during lumpectomy surgery to remove only the breast cancer tumor. While the lumpectomy incision is still open, doctors use a special device to deliver one large dose of radiation directly to the tumor site (the “tumor bed”) to treat any cancer cells that may remain after the tumor is removed.

Read More | 8 Min. Read

Breast radiation side effects

01/10/22 | BY: Neil K. Taunk

Radiation therapy, also called radiotherapy, is a very effective treatment for lowering the risk of recurrence in early-stage breast cancer and for managing pain or complications of metastatic breast cancer. While radiation destroys cancer cells, it also damages healthy cells near the area being treated, and so there can be uncomfortable side effects.

Read More | 14 Min. Read

Deep inspiration breath hold (DIBH) during radiation therapy

12/08/21 | BY: Neil K. Taunk

To protect the heart during left-breast radiation therapy, doctors use a technique called deep inspiration breath hold (DIBH). This breath-holding technique can minimize radiation exposure to the heart.

Read More | 9 Min. Read

Radiation schedules for breast cancer treatment

07/14/21 | BY: Neil K. Taunk

Radiation treatments are usually given in a series of short daily doses designed to kill cancer cells in the breast tissue. The type of radiation therapy, the dosage, and the number of days or weeks you’ll be treated during your radiation schedule depends on the characteristics of the cancer.

Read More | 14 Min. Read

Radiation therapy for breast cancer

07/14/21 | BY: Neil K. Taunk

Radiation therapy, also known as radiotherapy, directs high-energy x-rays to a specific part of the body to kill cancer cells. Radiation and other treatments focused on a certain part of the body are often called local therapy because they are “local” to one part of the body.

Read More | 14 Min. Read

Ovarian suppression


Ovarian suppression is surgery, radiation therapy or medicine that is used in premenopausal women to stop the ovaries from working.

Read More | 4 Min. Read

Types of hormonal therapy

11/04/19 | BY: Jennifer Winn

Hormonal therapy medicines are put into classes based on how they interact with the body’s natural hormones estrogen and progesterone. Some stop the body from making estrogen, while others prevent estrogen from helping the cancer cell grow.

Read More | 6 Min. Read


11/04/19 | BY: Jennifer Winn

Tamoxifen is a type of hormonal therapy called a SERM, or selective estrogen receptor modulator, a medicine that prevents estrogen signals from getting to breast cancer cells.

Read More | 6 Min. Read

Gonadotropin releasing hormone (GnRH) agonists

10/07/19 | BY: H. Irene Su

The gonadotropin releasing hormone agonists, or GnRH agonists, are a class of injectable medicines offered to pre- and perimenopausal women with breast cancer in order to temporarily suppress, or slow, ovarian function.

Read More | 5 Min. Read

Ado-trastuzumab emtansine

07/16/19 | BY: Pallav K. Mehta

Ado-trastuzumab emtansine (Kadcyla) is the targeted therapy trastuzumab (Herceptin) with the chemotherapy medicine emtansine attached. It may also be called T-DM1.

Read More | 5 Min. Read