By Lynda Williams, Senior medwireNews Reporter
Both current and former smoking have a significant impact on the prognosis of patients with nasopharyngeal carcinoma, Chinese researchers caution.
“It is clear that cigarette smoking not only promotes carcinogenesis in the normal nasopharyngeal
epithelium, but also affects the survival of patients with nasopharyngeal carcinoma,” say Fang-Yun Xie (Sun Yat-sen University Cancer Center, Guangzhou) and co-authors in Cancer Epidemiology Biomarkers & Prevention.
Overall, 1849 patients with nasopharyngeal carcinoma were followed-up for a median of 73.5 months during which time 8.1% experienced locoregional relapse, 12.6% distant metastases, and 20.4% of patients died. The 5-year overall and progression-free survival rates were 82.2% and 74.2%, respectively.
The team found current smokers and formers smokers had a significantly increased risk for death than never smokers (hazard ratio [HR]=1.67 and 1.46, respectively), after adjusting for a raft of confounding factors including gender, alcohol consumption, and tumor characteristics.
A similar relationship was also found for progression-free survival, with HRs of 1.74 and 1.41, respectively. Although current or former smoking did not significantly reduce survival for female patients and those with a history of drinking alcohol, the researchers say this may be due to the small patient numbers.
The team detected a dose–response effect, with heavy smokers (defined as >22 pack–years) having significantly poorer overall and progression-free survival than smokers with fewer pack–years. For each additional pack–year, the HR for both overall and progression-free survival increased by 2%.
The majority of patients received radiotherapy plus chemotherapy, while 23.4% were treated with radiotherapy alone. When the researchers examined the outcomes of the 495 patients who were treated with intensity-modulated radiotherapy or three-dimensional conformal radiotherapy, the impact of current and former smoking mirrored the whole group.
"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," Xie commented in a press release.
"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."
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