Lung cancer in women differs from lung cancer in men in many ways. Yet, despite obvious differences in our appearance, we tend to lump men and women together when talking about lung cancer. This is unfortunate, since the causes, response to various treatments, survival rate, and even symptoms to watch for differ. What are some facts about lung cancer in women?
Statistics About Lung Cancer in WomenLung cancer is the leading cause of cancer deaths in women, killing more women each year than breast cancer, uterine cancer, and ovarian cancer combined. While smoking is the number one cause, 20% of these women have never touched a cigarette.
Once considered a “man’s disease,” lung cancer is no longer discriminatory. In 2005, the last year for which we have statistics, 82,271 women (vs 107,416 men) were diagnosed with lung cancer, and 69,078 (vs 90,139 men) died.
While lung cancer diagnoses decreased each year from 1991-2005 for men, the incidence increased 0.5% each year for women. The reason for this is not completely clear.
Lung cancer in women occurs at a slightly younger age, and almost half of lung cancers in people under 50 occur in women.
CausesEven though smoking is the number one cause of lung cancer in women, a higher percentage of women who develop lung cancer are life-long non-smokers. Some of the causes may include exposure to radon in our homes, secondhand smoke, other environmental and occupational exposures, or a genetic predisposition. Recent studies suggest infection with the human papilloma virus (HPV) may also play a role.
Smoking StatusSome, but not all, studies suggest that women may be more susceptible to the carcinogens in cigarettes, and women tend to develop lung cancer after fewer years of smoking.
Lung Cancer TypesWhereas men are more likely to develop squamous cell lung cancer, another form of non-small cell lung cancer, adenocarcinoma is the most common type of lung cancer found in women.
BAC (Bronchioalveolar carcinoma) is a rare form of lung cancer that is more common in women. For unknown reasons, the incidence of BAC appears to be increasing worldwide, especially among younger, non-smoking women.
SymptomsWe hear about the symptoms of a heart attack being different in women from in men. The same could hold true for lung cancer. Squamous cell lung cancer (the type more common in men) grows near the airways, and often presents with the “classic symptoms” of lung cancer, such as a cough and coughing up blood. Adenocarcinomas (the type of lung cancer that is more common in women), often develops in the outer regions of the lungs. These tumors can grow quite large or spread before they cause any symptoms. Symptoms of fatigue, the gradual onset of shortness of breath, or chest and back pain from the spread of lung cancer to bone, may be the first sign that something is wrong.
Lung Cancer in Women – The Role of Estrogen
It is likely that estrogen plays a role in the development and progression of lung cancer and research is being done to define this further. Women who have their ovaries removed surgically before menopause may be at higher risk of developing lung cancer. Recent research suggests that treatment with estrogen and progesterone (hormone replacement therapy) after menopause may increase the risk of dying from lung cancer. In contrast, the use of estrogen therapy alone has been associated with a lower risk of dying from the disease.
In contrast, both the use of birth control pills and hormone replacement therapy (excepting those who use hormones after surgical menopause) are associated with a lower risk of developing lung cancer. This contrast between dying from, and development of, lung cancer, suggests that estrogen plays more than one role in lung cancer.
TreatmentWomen historically respond to a few chemotherapy medications used for lung cancer better than men. One of the new targeted therapies, erlotinib (Tarceva), also appears to be more effective for women. Women who are able to be treated with surgery for lung cancer also tend to fair better. In one study, the median survival after surgery for lung cancer was twice as long for women as for men.
On the other hand, even though the National Cancer Institute recommends that all patients with stage 3 lung cancer be considered candidates for clinical trials, women are less likely to be involved in clinical trials than are men.
SurvivalThe survival rate for lung cancer in women is higher than for men at all stages of the disease. Sadly, the overall 5-year survival rate is only 16% (vs 12% for men).
Awareness and FundingEven though many more women die from lung cancer than breast cancer, much more funding is devoted to breast cancer research than lung cancer research. According to the Lung Cancer Alliance, federal research funding in 2007 from the National Cancer Institute, Department of Defense, and Centers for Disease Control amounted to $23,754 per breast cancer death, and only $1,414 per lung cancer death. Due to a lower survival rate, and the symptoms of lung cancer (many survivors cannot walk and run for the cure), as well as the stigma, private fundraising also lags significantly behind that of breast cancer.
How Can Women Reduce Their Risk of Lung Cancer?Thankfully, even though lung cancer is the leading cause of cancer deaths in women, it is a largely preventable disease:
American Cancer Society. Cancer Facts and Figures 2009. http://www.cancer.org/Research/CancerFactsFigures/CancerFactsFigures/cancer-facts-figures-2009
Clague, J. et al. Menopause Hormone Therapy and Lung Cancer-Specific Mortality Following Diagnosis. The California Teaches Study. PLoS One. July 31, 2014.
Chlebowski, R. et al. Oestrogen plus progestin and lung cancer in postmenopausal women (Women’s Health Initiative trial): a post-hic analysis of a randomized controlled trial. Lancet. 2009. Sep 18. (Epub ahead of print).
Kazmi, N. et al. The role of estrogen, progesterone and aromatase in human non-small-cell lung cancer. Lung Cancer Management. 2012. 1(4):259-272.
Meinhold, C. et al. Reproductive and hormonal factors and the risk of nonsmall cell lung cancer. International Journal of Cancer. 2011. 128(6):1404-13.
Murthy, V. et al. Participation in Cancer Clinical Trials. Race-,Sex-, and Age-Based Disparities. Journal of the American Medical Association. 2004. 291:2720-2726.
National Cancer Institute. Lung Cancer Prevention (PDQ). Health Professional Version. Updated 02/27/04. http://www.cancer.gov/cancertopics/pdq/prevention/lung/HealthProfessional/page1/AllPages
Pesatori, A. et al. Hormone use and risk for lung cancer: a pooled analysis from the International Lung Cancer Consortium (ILCCO). British Journal of Cancer. 2013 Sep 3. (Epub ahead of print).
Radzikowska, E. et al. Lung cancer in women: age, smoking, histology, performance status, initial treatment and survival. Population-based study of 20,561 cases. Annals of Oncology. 2002. 13:1087-1093.
Yao, Y. et al. Hormone replacement therapy in females can decrease the risk of lung cancer: a meta-analysis. PLoS One. 2013. 14(8):e71236.