Broccoli Sprout Extract and Head, Neck Cancer

Broccoli sprout extract protected against oral cancer in mice and also proved tolerable in a small group of healthy human volunteers, according to a study by the University of Pittsburgh Cancer Institute (UPCI). 

The promising results will be explored later this year in a human clinical trial, which will recruit participants who are at high risk for head and neck cancer recurrence. The research is funded through Pitt’s Specialized Program of Research Excellence grant in Head and Neck Cancer, which receives its funding from the National Cancer Institute.

“People who are cured of head and neck cancer are still at very high risk for a second cancer in their mouth or throat, and, unfortunately, these second cancers are commonly fatal,” said lead author Julie Bauman, associate professor of medicine in Pitt’s School of Medicine and codirector of the UPMC Head and Neck Cancer Center of Excellence. “So, we’re developing a safe, natural molecule found in cruciferous vegetables to protect the oral lining where these cancers form.”

Previous studies, including large-scale trials in China, have shown that cruciferous vegetables with a high concentration of sulforaphane—such as broccoli, cabbage, and garden cress—help mitigate the effects of environmental carcinogens. Sulforaphane is an anticarcinogenic compound. 

Bauman collaborated with Daniel E. Johnson, a Pitt professor of medicine and a senior scientist in the UPCI Head and Neck Cancer Program, to test sulforaphane in the laboratory. For several months, Johnson and his team gave the anticancer compound to mice predisposed to oral cancer and found that it significantly reduced the incidence and number of tumors.  

“The clear benefit of sulforaphane in preventing oral cancer in mice raises hope that this well-tolerated compound also may act to prevent oral cancer in humans who face chronic exposure to environmental pollutants and carcinogens,” Johnson said.    

Bauman treated 10 healthy human volunteers with fruit juice mixed with sulforaphane-rich broccoli sprout extract. The volunteers had no ill-effects from the extract, and protective changes were detectable in the lining of their mouths, meaning it was absorbed and directed to at-risk tissue.

These findings were enough to prompt a clinical trial that will recruit 40 human volunteers who have been curatively treated for head and neck cancer. The participants will regularly take capsules containing broccoli seed powder to determine if they can tolerate the regimen and whether it has enough of an impact on their oral lining to prevent cancer. From there, larger clinical trials could be warranted.

“We call this ‘green chemoprevention,’ where simple seed preparations or plant extracts are used to prevent disease,” Bauman said. “Green chemoprevention requires less money and fewer resources than a traditional pharmaceutical study, and could be more easily disseminated in developing countries where head and neck cancer is a significant problem.”

Additional authors on this research are Pitt’s Yan Zhang, Malabika Sen, Daniel P. Normolle, Thomas W. Kensler, Sumita Trivedi, and Siddharth H. Sheth, as well as Jennifer R. Grandis, now at the University of California San Francisco, and Patricia A. Egner of Johns Hopkins University.