OU College of Medicine Researcher Publishes Major Study on E-cigarette Use and Chemotherapy Resistance

An OU College of Medicine researcher has published a groundbreaking new study suggesting that when people use electronic cigarettes while undergoing chemotherapy for cancer, they will likely receive much less benefit from the treatment.

Lurdes Queimado, M.D., Ph.D., recently published the study in Scientific Reports, a Nature Research publication and one of the world's leading journals. While much is known about the harmful effects of tobacco smoking, including during cancer treatment, researchers have less knowledge about e-cigarettes, also called vapes. Queimado's study is the first in the world to show that e-cigarettes, like regular cigarettes, can prevent chemotherapy from working as well as it should. The study was conducted in vitro, or in laboratory experiments, but the study's measures are predictive of a patient's response to cancer treatment. Her next step is to conduct a similar study in patients at OU Health Stephenson Cancer Center who are being treated for head and neck cancers and cervical cancer.

"When patients are diagnosed with cancer and are still smoking tobacco, they often ask, 'What if I switch to e-cigarettes during chemotherapy?' Until now, we have not known whether that would be a good option. What this study tells us is that, while e-cigarette vapors have fewer toxins than smoke, at least during cancer treatment patients should use all other smoking cessation tools to help them quit smoking instead of immediately switching to e-cigarettes," said Queimado, Director of Basic and Translational Research for the Department of Otolaryngology - Head and Neck Surgery in the OU College of Medicine, and a TSET Research Scholar at Stephenson Cancer Center.

Queimado's experiments focused on head and neck cancer cells that were treated with a common platinum-based chemotherapy called cisplatin. In the models of e-cigarette use, far fewer cancer cells died after the standard dose of cisplatin. Queimado's hypothesis was that the nicotine in e-cigarettes caused the resistance to chemotherapy, just as it does when people smoke tobacco. That was true, but she also found that other chemicals in e-cigarettes contributed to therapy resistance as well.

"We don't know yet what those compounds are, but we know that e-cigarettes contain chemicals that are not present in tobacco, and their effects when inhaled are poorly characterized," she said.

For oncologists, the implications of the study are significant. Studies show that over 60% of lung and head and neck cancer patients continue to smoke tobacco during their treatment, which has a host of negative implications. Now it appears that switching to e-cigarettes isn't the best alternative during cancer treatment; rather, patients should first take advantage of all other smoking cessation aids.

"Smokers and e-cigarette users who are unwilling or unable to quit during cancer treatment may need higher-than-standard cisplatin doses to receive the same therapeutic benefit as those who don't smoke or use e-cigarettes," Queimado said. "Because chemotherapy drugs like cisplatin have major side effects, higher doses might not be possible because they would be too toxic for the patient. Hence, other drugs might need to be considered for these patients."

Use of e-cigarettes has increased dramatically since the product hit the U.S. market in 2007. They are often advertised as a smoking cessation tool or as a safe alternative to combustible smoking because they contain fewer chemicals. However, e-cigarettes face very few restrictions or regulations, prompting the urgent need for researchers like Queimado to discover more information about their health effects.

In previous studies, she showed that e-cigarette vapor not only damages DNA, albeit less than tobacco smoke, but it also reduces a person's ability to repair DNA. Last year, she received a $2.25 million grant from the National Cancer Institute to study cancer risk in young adults who use e-cigarettes.

"We have known for years that head and neck cancer patients who continue to utilize traditional tobacco products after treatment have twice the rate of recurrence, and because of this we strongly encourage tobacco cessation and have resources available to help our patients quit," said Greg Krempl, M.D., Professor and Chair of the Department of Otolaryngology - Head and Neck Surgery in the OU College of Medicine. "E-cigarettes have been proposed as an assistance for tobacco cessation, a stepping stone toward abstinence. Dr. Queimado's work suggests that for cancer patients who are undergoing certain chemotherapy, this may not be the best option for assistance in tobacco cessation.

Her lab has shown vaping causes damage that might result in cancer formation, and has now shown, for the first time anywhere in the world, a possible 'side effect' of vaping during treatment that may reduce the effectiveness of cancer treatment and could ultimately compromise our chances of curing patients. While more studies are needed to confirm this effect in humans, a conservative approach now is to make patients aware of this potential risk when discussing tobacco cessation."

In addition to federal grants, Queimado's research has received significant local support. She is director of the Tobacco Regulatory Science Lab at the TSET Health Promotion Research Center, a Stephenson Cancer Center program that is funded by the Oklahoma Tobacco Settlement Endowment Trust (TSET). She has also received bridge grant support from the Presbyterian Health Foundation (PHF) and holds the Presbyterian Health Foundation Chair in the Department of Otolaryngology - Head and Neck Surgery, and her work has been funded by the Oklahoma Center for the Advancement of Science and Technology (OCAST).