Cooking meats at high temperatures through barbecuing or grilling leads to the production of chemicals that can increase cancer risk.
Study co-author Humberto Parada, Jr., of the University of North Carolina at Chapel Hill, and colleagues recently reported their findings in the Journal of the National Cancer Institute.
After skin cancer, breast cancer is the most common cancer among women in the United States. This year, it is estimated that around 252,710 new cases of breast cancer will be diagnosed in the U.S., and more than 40,000 women will die from the disease.
But despite these troubling statistics, breast cancer incidence and death rates are falling, which is largely due to earlier detection through screening and better treatments. According to the American Cancer Society, there are currently more than 2.8 million breast cancer survivors in the U.S.
The new study, however, suggests that the lifespan of women who have survived breast cancer may be cut short by eating high amounts of grilled, barbecued, or smoked meats.
Breast cancer and cooked meats
Previous research in animal models has shown that meats cooked at high temperatures - through grilling or pan frying, for example - may increase the risk of certain cancers, including breast cancer.
According to the National Cancer Institute (NCI), this is because such cooking methods can lead to the production of polycyclic aromatic hydrocarbons and heterocyclic amines, which are chemicals that can trigger changes to the DNA that increase cancer risk.
Parada and colleagues note that, while many studies have linked meats cooked at a high temperature to a higher risk of breast cancer, no studies have looked at whether the intake of such meats may affect survival after breast cancer.
To address this gap in research, the team interviewed 1,508 women who had received a diagnosis of first primary invasive or in situ breast cancer in 1996 or 1997.
At study baseline, all participants were asked about their consumption of four different types of grilled, barbecued, and smoked meats in each decade of life. Five years later, the women were asked about their intake of these meats during the intervening 5 years.
All-cause mortality increased with high intake of cooked meats
Over a median 17.6 years of follow-up, 597 of the women died. Of these deaths, 237 (39.5 percent) were associated with breast cancer.
Overall, compared with women who reported a low intake of grilled, barbecued, or smoked meats prior to a breast cancer diagnosis, those who reported a high intake of these meats were found to be at a 23 percent greater risk of all-cause mortality.
Women who reported a high intake of smoked beef, lamb, or pork were at 17 percent increased risk of all-cause mortality and a 23 percent increased risk of breast cancer-specific mortality, compared with those who reported a low intake.
Grilled, barbecued, and smoked meat intake over a lifetime was not linked to mortality, nor was annual intake of grilled and barbecued beef, lamb, pork, poultry, and fish prior to a breast cancer diagnosis.
Compared with women who consumed low amounts of grilled, barbecued, and smoked meats prior to or after a breast cancer diagnosis, those who reported a continued high intake were at a 31 percent increased risk of all-cause mortality, the researchers report.
Based on their findings, Parada and colleagues conclude:
"High intake of grilled/barbecued and smoked meat may increase mortality after breast cancer."