Trial Information

Differences in the Presentation, Outcome and Response to Treatment Between Never- Smokers and Smokers With Non- Small Cell Lung Cancer.

Lung cancer is the most lethal of all malignant tumors affecting humans. In the United
States alone an estimated 160,440 patients died of lung cancer 2004[1]. It is well known
that tobacco smoking is a major risk factor and accounts for the majority of all lung cancer
cases. But there is a sub group of patients with lung cancer who have never actively smoked
tobacco. This group exhibits certain unique characteristics which separates them from lung
cancer in smokers. It has been shown that never- smokers with adenocarcinoma have better
outcomes in terms of overall survival as well as lung cancer specific survival when compared
to current smokers with adenocarcinoma of the lung[2]. Also patients who are current
smokers at diagnosis have decreased survival when compared to people who quit smoking[3].
The improved survival in never smokers could be due to several reasons. Such as increased
incidence of co-morbid factors in smokers as result of exposure to tobacco smoke,
differences in metabolism of chemotherapeutic agents or a reflection of differences in the
underlying molecular biology of the tumor.

It has been demonstrated that chromosomal abnormalities are common in lung cancer patients
with a smoking history when compared to never- smokers[4]. Gene mutations such as p53
mutations are more frequent in never- smokers than in previous smokers[5]. In addition
mutations that are specific only to lung cancer in never smokers have been discovered,
demonstrating the possibility of a separate or overlapping carcinogenesis pathway for lung
cancer in never smokers vs. smokers [6].