Study suggests extending breast cancer treatment might reduce recurrence


Approximately 11,000 of those studied had cancer crop up in the lung, bone, or liver in the 15 years after their initial hormone therapy treatment concluded.

By Sophia Eppolito Globe Correspondent 

Extending hormone therapy treatment for breast cancer patients past the typical five years could reduce the likelihood of recurrence, according to a New England Journal of Medicine report published Thursday.

Scientists analyzed nearly 63,000 women who had ER-positive breast cancer. This type of cancer is fueled by estrogen, a hormone that can stimulate cancer cells to grow and divide.


At the start of the trials, each patient was disease-free after undergoing five years of hormone treatments such as tamoxifen or aromatase inhibitors. These pills either blocked estrogen’s effect or shut off its supply. The scientists studied the women’s progress during the 15 years following that five-year mark.

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Over the course of that study period, a steady number of the women found that their cancer had spread throughout their body. Approximately 11,000 of those studied had cancer crop up in the lung, bone, or liver in the 15 years after their initial hormone therapy treatment concluded, according to Cancer Research UK, which helped fund the study.

The study found that the women who originally had large tumors and cancer that had spread to four or more lymph nodes were most likely to be at risk of the cancer returning over the next 15 years (41 percent).

Women with smaller cancers that hadn’t spread to the lymph nodes had the lowest risk (13 percent) of their cancer spreading.

Eric Winer, director of the Breast Oncology Center at the Dana-Farber Cancer Institute, said the most important finding from this study had to do with the possible risks after this kind of therapy is completed.


“It’s just important to keep in mind that some types of breast cancer place a woman at risk for many, many years after the diagnosis,” Winer said. “And as doctors, what we have to figure out is how to reduce that risk.”

Winer said most doctors were already familiar with the findings of the study.

Recent studies have suggested that an additional five years of endocrine therapy is more effective, but there are corresponding side effects. These effects might include menopausal symptoms, osteoporosis, joint pain, and carpal tunnel syndrome.

Winer said prolonged therapy is part of the answer, but it isn’t the whole answer. He also explained that it is important to realize that this study has limitations.

“These are patients from 20, 30 years ago. Women are diagnosed more frequently at an earlier stage now,” Winer said. “For women that are concerned about this, they should talk to their doctors and really get a sense of what their risk is of getting a late occurrence.

“The last thing we want to do is scare everyone with this data.”

Sophia Eppolito can be reached at
Follow her on Twitter @SophiaEppolito.