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New research finds a full chemo dose may be best for a certain type of breast cancer. Getty Images
  • Breast cancer is diagnosed in 245,000 women in the United States each year.
  • A new study finds a full course of chemotherapy is the best option for a certain type of breast cancer.
  • Researchers wanted to know whether a slightly lower dosage was just as safe as a full dosage.
  • They found reducing chemo doses after surgery was associated with a lower survival rate.

Breast cancer is the second most common cancer among U.S. women, with about 245,000 cases diagnosed every year, according to the Centers for Disease Control and Prevention (CDC).

While not all women with breast cancer will need chemotherapy, new research published in the Journal of the National Comprehensive Cancer Network (JNCCN) reveals the timing and dose used significantly affects survival rates in certain cases.

Researchers looked at the impact of reducing chemo doses after breast surgery (called adjuvant therapy) using a combination of four different drugs: 5-fluorouracil, epirubicin, cyclophosphamide, and docetaxel (FEC-D). The drugs were given in four to six treatments cycles.

The study found that both the overall and 5-year disease-free survival rate was worse in those who received less than 85 percent of the recommended chemotherapy dose over six treatment cycles.

“What surprised us the most was how dramatically early reductions in chemotherapy affect survival compared to later modifications,” said Dr. Zachary Veitch, from the department of oncology in the University of Calgary Tom Baker Cancer Centre, in a statement.

This study used data from 1,302 women with stages 1 to 3 HER2-negative breast cancer who were treated with adjuvant chemotherapy between 2007 and 2014. The information came from the Alberta Cancer Registry (ACR) in Canada.

Breast cancer that’s HER2-negative means it doesn’t have abnormally high levels of proteins called human epidermal growth factor receptor 2.

High levels of these proteins on breast cancer tumors result in HER2-positive breast cancer. Therapies for HER2-positive breast cancer can target these proteins, but these treatments don’t work as well for people with HER2-negative breast cancer.

Veitch says this research can help oncologists and patients as they plot out a treatment plan, especially if they anticipate early treatment will be difficult.

“Often the first cycle of chemotherapy can be difficult for patients, and oncologists must convey the need for maintaining initial dose intensity, while using other medications to control side effects and manage comorbidities,” explained Veitch.

Although, when researchers split the lower-dose group in two based on dose reduction during the first three cycles versus the last three, they found the outcomes weren’t worse when doses were reduced during the later cycles.

“The majority of cancer cells that are sensitive to chemotherapy may be killed in the first few treatments, rather than in the later treatments. Thus, reducing the dose late may not have as much of an impact,” Veitch speculated in the statement.

Dr. Lindsay Keith, a surgical breast oncology specialist in Murfreesboro, Tennessee, told Healthline that chemotherapy can affect patients differently and this research will help oncologists treat patients.

“In general, the most common side effects for the combination of medications often used to treat breast cancer are hair loss, nausea and/or vomiting, low white blood cells, and brittle nails,” Keith said.

“Every patient reacts to chemotherapy differently, and a medical oncologist will help explain these side effects in more detail, as well as help treat them,” she added.

“We stage cancer based on its size, whether it’s spread to the lymph node, and whether it’s spread to other parts of the body,” said Dr. Roshni Rao, FACS, chief of the breast surgery division and Vivian L. Milstein associate professor of surgery at Columbia University, told Healthline.

“This helps us compare across many patients what the outcomes are to different treatments and determine how aggressive treatment may need to be,” she said. Rao wasn’t associated with the study.

To make a diagnosis, doctors need to find out what type of breast cancer a patient has.

Some breast tissue will be removed during surgery or biopsy and sent for testing. This finds out which genes and proteins are involved in breast cancer development. That determines the best treatment options.

“The stages are from 0 to 4, with stage 4 considered incurable. However, all stages below 4 are potentially curable. The lower the stage, the better a patient’s prognosis,” elaborated Dr. Hikaru Nakajima, a breast cancer treatment expert with the St. Luke’s University Health Network.

According to Nakajima, “HER2-negative cancer accounts for approximately 70 percent of breast cancer, and usually, it’s not the most aggressive type.”

Keith points out there are several known risk factors for breast cancer. Some are genetic. Others are related to lifestyle.

“Family history, especially multiple first-degree family members with breast cancer, is a risk factor for developing breast cancer,” Keith explained.

“Certain genetic mutations can greatly increase one’s risk for development of breast cancer, although only about 10 to 15 percent of all breast cancers are caused by a known gene mutation,” he said.

Rao says other risk factors can include when a woman gets her period or whether or not she has children.

“Getting older, starting periods at a young age, not having kids before the age of 30, and not breastfeeding before 30 will also increase breast cancer risk,” Rao said. “But there are ways to reduce the risk.”

Rao says people can take steps to reduce their risk for breast cancer through healthy lifestyle choices. Her recommendations include:

  • maintaining a healthy weight
  • limiting alcohol consumption
  • getting sufficient exercise

Breast cancer affects about a quarter-million U.S. women every year. New research finds the timing and dose of chemotherapy can significantly influence survival rates for one type of breast cancer.

While 1 in 8 U.S. women will experience breast cancer in their lifetime, there are lifestyle changes that can reduce that risk.