Though they don't often make the favorite menus of most men, cauliflower and kale -- along with cabbage, broccoli, brussels sprouts, kohlrabi, watercress and turnips -- contain a chemical that is a significant cancer-preventive.

But add curry powder to the mix, the researchers say, and the vegetables and spice are effective in treating established prostate cancers, the second-leading cause of cancer death in American men.

It all boils down to a pair of crucial chemicals that "hold real potential for the treatment and prevention of prostate cancer," the Rutgers study stated. The vegetables contain phenethyl isothiocyanate, or PEITC, while the curry contains curcumin, a yellow pigment found in the spice itself.

Both are considered phytochemicals -- nonnutritive substances in plants that have protective, antioxidant or anti-disease qualities.

"The bottom line is that PEITC and curcumin, alone or in combination, demonstrate significant cancer-preventive qualities in lab mice, and the combination of PEITC and curcumin could be effective in treating established prostate cancers," said Ah-Ng Tony Kong, the study's lead author and a professor of pharmaceutics at Rutgers.

Though a half-million new cases of prostate cancer occur in the U.S. annually, incidence and death rates have not lessened despite decades of research for treatments or a cure. Advanced cases of prostate cancer cells are "barely responsive" to rigorous chemotherapy or radiation treatment, Mr. Kong said.

He was inspired to investigate diet as a supplementary therapy after noting that while prostate cancer is common in the U.S., the disease is rare in India, where plant-based diets and curry are the norm.

Curry itself has prompted other significant findings. Last year alone, the University of Texas found it inhibited the growth of both skin cancer and breast cancer cells, while the University of California at Los Angeles found it stopped the spread of harmful brain plaque in patients with Alzheimer's disease.

Mr. Kong had previously found convincing evidence, he said, that the two chemical compounds quelled prostate cancer cells grown in the laboratory. He has since tested his theory on mice injected with the cancer cells. Three times a week for a month, the test mice then received injections of PEITC and curcumin.

Separately, the compounds "significantly retarded the growth of cancerous tumors," Mr. Kong noted. "Using PEITC and curcumin in tandem produced even stronger effects." The research team also evaluated therapeutic potential of the compounds in mice with advanced prostate cancer to find they "significantly reduced tumor growth."

The study was published by Cancer Research, a journal of the Philadelphia-based American Association for Cancer Research.