Three significant studies this year have already shown that coffee may have a health benefit when it comes to cancer prevention. 

• January 2015: National Cancer Institute published a study showing that people who drank four cups of caffeinated coffee a day had a 20% lower risk of melanoma than non-coffee drinkers.
• February 2015: AACR journal found that women who drink four cups a day have a reduced risk of endometrial cancer.
• Late March 2015: U.K. researchers released an analysis of 34 studies conducted around the world and concluded that coffee consumption—even just one cup a day—reduces the risk of liver cancer

Scientists still cannot determine what ingredient in coffee stunts tumor growth or reacts with cancer cells. But all these studies are leading us to the root connection.

Coffee and Breast Cancer Recurrence

A new study released in April shows caffeine in coffee may protect against breast cancer recurrence. 

• 2 cups per day inhibits the growth of tumors and reduced risk of recurrence in women diagnosed w/breast cancer
• Key ingredient: Caffeine in this case

The study, out of Lund University and Skane University Hospital in the UK combined information about the patient's lifestyle and clinical data. 

• Studied patients that were treated with Tamoxifen
• Tamoxifen: synthetic drug used to treat breast cancer and infertility in women
  • Acts as an estrogen antagonist
• 1090 breast cancer cancer patients
• Over 500 women that had drank at least two cups/day had only ½ the risk of recurrence verses those who drank no coffee at all
• Those who drank 2 cups/day had smaller tumors and lower proportion of the hormone-dependent tumors

Why Caffeine in Coffee?

Caffeine and caffeic acid found in coffee reacted with breast cancer cells and cells reduced, especially in combination with the drug Tamoxifen. Caffeine and the drug have an effect together on the cells and turn off signaling pathways that the cancer cells require to grow.

There has been previous research linking breast cancer and coffee. In other studies, women who drank more than 5 cups/day may reduce risk of one type of breast: estrogen-receptor positive breast cancer.

Age is a definitely a factor as shown in a Swedish study of 6,000 women.

Pre-menopausal women, 4 cups/day has been associated with a 38% lower risk of breast cancer. For pre-menopausal women at a high risk because they carry the BRCA1 and BRCA2 mutation, the risk for breast cancer is reduced by 25-70% w/consuming 4-6 cups/day (only regular coffee, not decaf)