Cigarettes are a cancer patient’s crutch and curse.

Scientists know that the first round of chemotherapy and radiation is a patient’s best chance for surviving the disease, but smoking during treatment can turn the cancer drugs toxic and cut their effectiveness by up to 50 percent.

That’s why a radiation oncologist and his team of scientists are doubling down the Medical University of South Carolina’s efforts to help cancer patients quit smoking.

It’s more than just telling patients they need to quit. It’s helping them figure out how, said Dr. Graham Warren, vice chairman for research in radiation oncology at the MUSC Hollings Cancer Center.

“Unfortunately a lot of people who try to quit are not able to quit the first time, and most patients when you see them, especially after diagnosis of cancer, have tried to quit three, four, five times in the past,” Warren said.

Warren is developing programs to help oncologists in Charleston and across the state determine if their patients are smokers, and ways to help them stop by guiding them through the decision process, prescribing smoking-cessation drugs and connecting them with counselors. The programs will roll out at MUSC this year, he said.

Meanwhile, the American Association for Cancer Research issued a statement last week calling for the oncology community across the country to start assessing and documenting tobacco use among patients during every visit.

“Smoking-cessation treatment has long been regarded as a key cancer prevention strategy. However, research has shown that such treatment is often lacking in oncology settings,” the association said in the statement.About 20 percent of the general population smokes. The estimated percentage is higher among cancer patients, Warren said. About 500,000 men and women out of an approximate 1.5 million new cancer patients every year smoke.

Warren has studied cancer cells of several varieties under a microscope. He said scientists can tell that tobacco use during chemotherapy and radiation increases the cancer growth and makes more blood vessels in cancer cells. It also can destroy healthy tissue. And this doesn’t just affect head, throat and lung cancer, he said. Quitting smoking during cancer treatment benefits nearly all forms of the disease.

Matthew Carpenter, a clinical psychologist at MUSC who studies tobacco use, said that while a cancer diagnosis can provide the motivating factor to quit smoking, it’s much easier said than done.

“If you think about a person who smokes a pack a day, that’s 20 cigarettes, there’s all kinds of associations that are created over 20, 30 years of smoking, and those don’t get unlearned overnight,” Carpenter said.