Radiotherapy is less effective on ex-smokers with cancer than those who have never lit up

Patients with head and neck cancer who have never had a cigarette respond far better to radiotherapy than former smokers a study has found.

Scientists from the UC Davis Cancer Center found those with a history of smoking were more likely to die from their disease and more likely to experience a recurrence after radiotherapy.

Study leader Dr Allen Chen said: ‘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.

A study looking at the effect of radiotherapy on head and neck cancer found 82 per cent of non-smokers were disease-free after three years compared to 65 per cent of ex-smokers

A study looking at the effect of radiotherapy on head and neck cancer found 82 per cent of non-smokers were disease-free after three years compared to 65 per cent of ex-smokers

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.’

Dr Chen suspects one possible explanation is that head and neck cancer is stronlgy linked to the human papillomavirus in people who haven’t smoked.

He said HPV-related tumours may express a substance that triggers the body’s immune system and this could enhance the effects of radiation.

Dr Chen compared 70 patients with mouth and throat cancer who had a history of smoking with 70 who said they had never smoked.

Patients who continued to smoke during treatment were not included in the study.

Subjects were evenly matched based on age, gender, ethnicity, primary tumor site, disease stage and treatment history.

The analysis found that 14 of the 70 ‘never-smokers’ experienced a recurrence of their disease compared to 26 patients who had a history of smoking.

In addition, 82 per cent of never-smokers were disease-free after three years compared to 65 per cent of patients who had smoked.

Those who had never smoked had a lower incidence of complications related to treatment than those who had smoked.

Dr Chen said the next step in the research is to identify biological or genetic differences among smokers and never-smokers diagnosed with head and neck cancers and treated with radiation therapy that might account for the differences in prognosis.

‘We are in the process of conducting several laboratory experiments designed to better understand why cancers arising from never smokers are so exquisitely radiosensitive,’ he said.

source: www.dailymail.co.uk

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