(RxWiki News) The Epstein-Barr virus can cause a throat cancer that’s rare in this country, but more common in Asia. Another cause of this throat cancer is smoking, which seems to have a profound impact on survival.
A new study looked at the impact of smoking on nasopharyngeal carcinoma, a cancer that develops in the upper throat behind the nose.
Former and current smokers, the study discovered, were more likely to see this throat cancer spread (metastasize) or return and lead to death than never smokers.
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Fang-Yun Xie, MD, professor in the Department of Radiation Oncology at the Sun Yat-sen University Cancer Center in Guangzhou, China, led a team of researchers who studied the role of smoking in the disease course of nasopharyngeal carcinoma.
This throat cancer will be diagnosed in just under 3,000 patients in the US this year — 0.5 to 2 people out of 100,000 — while in Southern China, nasopharyngeal cancer is seen in as many as 30 out of 100,000.
The researchers followed 1,849 newly diagnosed nasopharyngeal carcinoma patients for up to eight years for this study.
The study tracked patient overall survival, progression-free survival (the time during which the disease doesn’t worsen), locoregional relapse-free survival (time from treatment until the disease spreads to the area of the original tumor) and distant metastasis-free survival (time from treatment to metastasis to distant organs).
The researchers found little difference in the outcomes of former smokers and current smokers, which the authors attributed to the small number of former smokers involved in the study.
During the study period, the researchers found the following at five years:
- Overall survival of smokers (current and former) was 75.6 percent, compared to 88.4 percent for never smokers.
- Progression-free survival of smokers was 65.6 percent versus 82.4 percent among participants who had never smoked.
- Locoregional relapse-free survival was 89 percent among smokers and 94.4 percent for never smokers.
- Smoker distant metastasis-free survival was 83 percent among smokers, compared to 90.7 percent among never smokers.
Compared to participants who had never smoked, nasopharyngeal carcinoma patients who smoked heavily were 3.3 times more likely to die of the disease, 2.5 times more likely to see the disease progress and 2.7 times more likely to have the cancer spread to distant organs.
The more an individual had smoked in terms of pack-years (number of packs smoked daily over the years, i.e., one pack a day for 30 years equals 30 pack-years), the higher the risks of disease progression or death. This is called a dose-response relationship.
Dr. Xie said in a statement, "Previous studies have found that cancer patients resume smoking after treatment because of a higher perceived difficulty of quitting, and lower perceptions of their cancer-related risk. Our finding that cigarette smoking lowers the chance of survival for nasopharyngeal carcinoma patients, with a dose-response relationship, is a key fact that the general audience should keep in mind,” Dr. Xie said.
This study was published November 19 in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.
Research for the study was funded by the National Natural Science Foundation of China and the Science Foundation of Key Hospital Clinical Program of Ministry of Health of China.
The authors declared no conflicts of interest.