Those are the findings of a Swedish study involving women with breast cancers driven by the hormone estrogen.
"Enjoy drinking coffee."
Researchers at Lund University in Sweden followed breast cancer survivors who were taking tamoxifen for five years. Tamoxifen is a hormone therapy commonly used to block estrogen.
Helena Jernström, associate professor of Experimental Oncology at Lund University, led the study.
This team of researchers has previously found coffee consumption to be linked to a lower risk of developing certain kinds of breast cancer.
Coffee also has been shown to interfere with the growth of cancer cells.
This observational study, which is the weakest of all types of research studies, involved collecting information from 634 breast cancer survivors between 2002 and 2008.
Approximately half of the survivors took tamoxifen. The median age was 60 years old.
The study members were asked to complete questionnaires before surgery and during medical follow-up visits after three to six months, one, two and three years, and then at home at five, seven and nine years after surgery.
The median follow-up was five years.
Participants were asked about a number of things, including lifestyle habits such as smoking, alcohol and coffee consumption.
Survivors being treated with tamoxifen for estrogen-receptor positive (ER+) tumors who drank two or more cups of coffee a day had less than half the recurrences of breast cancer compared to those who drank low or no amounts of coffee.
Moderate to high coffee consumption was also associated with a lower risk of early distant metastasis (spread) compared to low consumption.
The reason for this association is not fully understood. One theory is that coffee turbocharges tamoxifen to make it more efficient.
While this study found that coffee was associated with fewer early breast cancer events, the authors noted “…the long-term effects of coffee consumption are unknown since patients with ER+ breast cancer tend to experience later events than patients with ER- (estrogen-receptor negative) tumors.”
“If the main finding of this study is confirmed in an independent cohort, patients should be informed of the potential benefits of combining coffee consumption with tamoxifen treatment,” the authors wrote.
"Lifestyle does matter, both in the prevention of and the survival from breast cancer," breast cancer specialist Christopher O. Ruud, MD, with Austin Cancer Centers, told dailyRx News. "This observational study is interesting and worth following up with additional research."
This study was published April 24 in Cancer Causes Control. This work was supported by grants from The Swedish Cancer Society, Swedish Research Council, Medical Faculty at Lund University; Mrs. Berta Kamprad’s Foundation, Gunnar Nilsson Foundation, Swedish Breast Cancer Group, South Swedish Health Care Region and the Lund Hospital Fund. No conflicts of interest were reported.