Precision Treatment for Breast Cancer

With all the breast cancer awareness campaigns in October, there may be an impression of breast cancer as a “fluffy, pink disease,” with the idea that you’ll be fine if you just get a mammogram, says Maryam Lustberg, MD, MPH, director of The Breast Center at Smilow Cancer Hospital and chief of Breast Medical Oncology at Yale Cancer Center. 

But even though there have been advances in breast cancer screening and treatment, 40,000 women still die from the disease each year, she points out.  

“October can be a trigger,” she notes. “Some people who are reading this article may have lost a family member to breast cancer. Others might be dealing with a diagnosis right now.” 

The awareness campaigns can be used for good but should “never make any woman or man feel ashamed if their cancer didn’t respond to treatment—or if they didn’t get a mammogram,” Dr. Lustberg says.

Regardless of how awareness campaigns are received, it’s important to recognize that there has been tremendous progress in breast cancer treatment over the years. 

We talked with Yale Medicine breast cancer experts about treatment and prevention trends, including the push for individualized treatment, or “precision medicine,” as it’s sometimes called. 

When it comes to treating breast cancer, doing less—not more—is often what’s best for patients, especially when it comes to surgery. 

“Overwhelmingly, the breast oncology community is trying to de-escalate unnecessary treatment or over-treatment, and also to spare our patients the side effects of treatment they may not benefit from,” says Rachel Greenup, MD, MPH, chief of Breast Surgical Oncology at Smilow Cancer Hospital.

This effort is based on continued advances in the understanding of breast cancer, including that it is not just one disease, but different types that can be targeted in ways tailored to each patient.  

“We have honed our approach. We are now able to sub-type different breast cancers,” Dr. Lustberg says. “It used to be that everyone was given the same chemotherapy, for example. But now that we understand what drives certain types of breast tumors, we know that one woman might need a certain surgery—as well as less chemo and less radiation—compared to another. And that knowledge has changed everything.” 

If you or anyone you love has had cancer, you may have heard about lymph nodes, which are small organs that contain immune cells and filter out foreign substances, including cancer and infections, from the body. Many lymph nodes are located in the neck, armpit, chest, abdomen, and groin. 

When cancer cells break away from a tumor, they can spread to lymph nodes. 

It used to be that women with early-stage breast cancer would have all of the lymph nodes underneath their arm surgically removed and sent to a pathologist. If the nodes were cancerous, that would indicate that the cancer had started to spread outside of the breast, says Mehra Golshan, MD, MBA, a Yale Medicine breast surgeon and director of the Breast Cancer Program for Yale Cancer Center, Smilow Cancer Hospital, and Smilow Cancer Hospital Care Centers.

“That surgery and accompanying radiation, unfortunately, left many women with lymphedema, or swelling of the arm. This can be a very difficult and long-lasting side effect for patients to manage in the survivorship phase,” Dr. Greenup says. 

But since the 1990s, surgeons have used a technique called sentinel lymph node biopsy. The sentinel lymph node is the first lymph node to which cancer is expected to spread, given the flow of the body’s lymphatic system, from its primary tumor. If cancer cells are found in the sentinel lymph node, it’s a sign that the cancer has become metastatic, meaning it’s begun to spread from the original tumor site to other parts of the body. 

During a sentinel lymph node biopsy, a blue or radioactive dye is injected into a woman’s breast, where it travels through the bloodstream to the nodes. The surgeon uses a probe to find the sentinel lymph node containing the radioactive or blue dye. It is then removed and sent to a pathologist for study. If the node is negative for cancer, no further surgery is needed. 

If it is positive, however, the surgeon would typically go back in and remove more nodes. 

But that plan is changing, too. There are cases now where nonsurgical treatments may be recommended instead—eliminating the risk for lymphedema. If the patient planned to receive a lumpectomy (a surgery to remove cancerous breast tissue), for example, a positive sentinel lymph node means the next step will be radiation—and not further removal of lymph nodes, Dr. Lustberg says.  

And that’s just one example. “A randomized study found that for women who meet certain criteria, as long as they went on to have radiation, it didn’t make any difference if they had additional lymph nodes removed,” she adds. 

Dr. Greenup is hopeful that this could mean fewer unnecessary surgeries for some patients. She says additional studies are continuing, including a large, national clinical trial in which Smilow is participating. 

“We are looking to see if the combination of systemic therapy, such as chemotherapy and/or endocrine therapy—in addition to radiation—is as effective as surgical removal of the lymph nodes, without the side effect of lymphedema,” she says. 

There have also been advances in genetic testing in recent years, Dr. Golshan says. 

“In the past, we would test for BRCA1 and BRCA2, as was done for Angelina Jolie and Christina Applegate,” he says, speaking of the mutations to those two genes that increase the risk of breast, ovarian, and other cancers. 

But since about 2014, most genetic tests identifying breast cancer risk look for mutations in additional genes, including one called PALB2.

“We are past the era of only talking about BRCA mutations when it comes to hereditary breast cancer risk,” says Amy Killie, MS, CGC, (certified genetic counselor) at the Smilow Cancer Genetics and Prevention Program. “There are a number of others we routinely test for, including PALB2, which is a moderate- to high-risk genetic mutation that translates into a risk of breast cancer ranging from 40% to 60% in a person’s lifetime.” (These patients also have a higher risk of pancreatic cancer, she adds.)

With a BRCA1 mutation, a woman’s risk of breast cancer is about 60% to 75%, and it’s 50% to 75% for a BRCA2 mutation, Killie adds. By comparison, the average woman’s risk of developing breast cancer during her lifetime is about 13%. And it’s also important to remember that only 5% to 10% of breast cancers are hereditary, Killie says. 

If a woman had genetic screening six years ago or more, she may want to consider talking to her physician about new testing, Killie says. This isn’t just because of the discovery of the PALB2 mutation; the BRCA testing has changed as well. “There are mutations to BRCA1 and 2 that we weren’t able to detect 10 years ago, and now we can,” Killie explains. 

Hereditary breast cancer tests, which are conducted through a blood or saliva sample, were once typically reserved for women who had breast cancer or were considered at high risk of developing it. That’s no longer the case, says Dr. Lustberg. “If we strictly followed that, we might miss women with breast cancer who have a genetic predisposition to it,” she says. “So, now you are seeing a movement to get more women tested, and some researchers are calling for universal testing.” 

Killie points out that men who have a family history of breast cancer (male or female) should also consider genetic testing. 

“The most common cancers associated with BRCA1 and 2 mutations are breast and ovarian cancers, but others include pancreatic cancer and melanoma. A family history of pancreatic cancer is therefore another reason to pursue this testing. Melanoma is technically seen in BRCA1 and 2 mutations, but at a much lower risk. So, a family history of melanoma wouldn’t be enough to warrant genetic testing,” Killie says. “And in men, we see a risk not only of breast cancer, but also of prostate cancer, which tends to be more aggressive.”  

When a woman tests positive for BRCA1 or 2 mutations, she can consider a number of options and recommendations based on other risk factors in her family history. For instance, she might do enhanced screening, including breast MRIs and mammograms at an earlier age. Some women may consider a prophylactic single or double mastectomy and also removal of the ovaries. (Actresses Jolie and Applegate both had double mastectomies and removed their ovaries.)

For women with a PALB2 mutation, additional and earlier screening is recommended, but there isn’t enough data to show bilateral mastectomy is warranted, Killie says. “And with ovarian cancer, the risk is about the same as having a first-degree relative with ovarian cancer,” she adds. 

As Breast Cancer Awareness Month continues, even though there is still more work to be done, it’s important to recognize the progress made in breast cancer treatment. 

“We have come a long way in the last 50 years, allowing women to remain whole, both physically and emotionally, as they are treated for breast cancer without compromising on excellent cancer outcomes,” says Dr. Greenup.