A pioneering study from UC Davis Cancer Centre by Allen M. Chen and his fellow researchers has revealed the fact that for cancers of the head and neck, those who have never smoked have much better survival rates than smokers after the application of radiation therapy. This unique research outcome is one of its kind, probing into prognosis variations resulting from a patient’s smoking history.
According to Chen, ‘There is something unique about the biology of head and neck cancers among non-smokers that makes them more amenable to cure by radiation therapy’. He further states, ‘These tumors just melt after a few doses of radiation. If we could understand why, there would be important implications for new drugs and treatments’.
Chen brings across a few possible explanations which might enlighten cancer research and treatments. His foremost suspect for propelling this difference in radio therapy reception amongst patients is human papillomavirus (HPV), a sexually transmitted disease primarily associated with head and neck cancer of never-smoking patients.
Chen said, ‘The most common theory is that these tumors express a characteristic viral antigen on the cell surface that makes the immune system recognise the cancers more readily, which may enhance the effects of radiation’. A further theory by Chen implies that non-smoking patients carrying HPV-related tumors have lesser number of mutations in key genes critically responsible for radiation purposes.
To further impose his insinuations empirically, Chen compared 70 smoking patients diagnosed with non-metastatic squamous cell carcinoma of the mouth and throat from the UC Davis Department of Radiation Oncology with another 70 non-smoking patients, considering the subjects evenly on the basis of age, gender, ethnicity, stage of disease, history of treatment and primary tumor sites. The results turned out to be immensely impressive.
Chen’s study revealed that 14 of the 70 never-smokers experienced a reappearance of the disease as compared to the 26 patients having a smoking history. Furthermore, 82 percent of the non-smokers continued to be free from the disease after a period of three years as compared to the smoker patients. Most importantly, the patients who never had a smoking history underwent minimal treatment complications than the smokers.
Chen’s analysis is proving to be a groundbreaking incident in the history of cancer research and treatment. His subsequent endeavour is to identify biological or genetic differences among smoking and never-smoking head and neck cancer patients who are undergoing radiation therapy. He announces, ‘We are in the process of conducting several laboratory experiments designed to better understand why cancers arising from never smokers are so exquisitely radiosensitive.’ This might be the answer to all queries regarding differences in prognosis.
Source: American Journal of Clinical Oncology