Lung cancer has been thought to be a man’s disease for a long time. However, research shows 80% rise in lung cancer in women. Not only is almost 50% of the lung cancer diagnosed in women, it is the leading cause of cancer deaths in women globally, killing more women each year than breast, uterine, and ovarian cancer combined. In Singapore it is the 2nd leading cause of cancer death after breast cancer.
While smoking is the number one cause of lung cancer, about 16% of women who develop the most common type of lung cancer (adenocarcinoma) have never smoked. Researchers have also found that in the age group of 30 to 54, women are more likely than men to develop lung cancer. Men are commonly diagnosed with squamous cell carcinoma type of lung cancer which affects the wind pipes.
The irritation of these wind pipes causes coughing and coughing out blood forcing the person to seek medical help early. However, women are commonly diagnosed with adenocarcinoma type of lung cancer which starts at the periphery of the lung. Since this type of lung cancer is located far away from the wind pipes, it does not cause symptoms of cough and hence doesn’t come to notice until late.
So what is the reason? Women are more sensitive to cancer causing chemicals in cigarettes and can develop lung cancer from smoking for fewer number of years than men likely because they are unable to repair their DNA damaged by smoking.
Oestrogen (the female hormone) has also been shown to be responsible as it makes women more sensitive to cancer causing chemicals making the cancer cells grow as studies have found that menopause (with drop in oestrogen levels) reduces the risk of lung cancer.
Among women, certain cancer driving mutations are more common like EGFR.
Despite these negative facts, studies show that women respond better to lung cancer treatment than men. The reason is unclear, but it may be due to hormonal differences. Women who have lung cancer surgery tend to respond better than men with these procedures. In one study, the five-year survival rate post-surgery was 75.6% for women versus 57.9% for men. Women also respond better to chemotherapy than men. In addition, since lung cancer in women often carries EGFR mutation, more patients in this group are suitable for the targeted therapy (tablet) comprised of EGFR inhibitors (Irresa, tarceva) than men.
What you can do? Stay vigilant and beware that although breast and ovarian cancers are common in females, the number 1 killer among all cancers in females is still lung cancer globally and 2nd most common cause of cancer death in Singapore.