According to the American Cancer Society, lung cancer is the second most common type of cancer in both men and women, with more than 200,000 Americans predicted to be diagnosed in 2017 alone.
Despite far fewer women smoking cigarettes than men, they still account for nearly half of all new cases. And even though cancer deaths in men have been declining since 1990, lung cancer deaths among women continue to rise.
In this article, we look at lung cancer specifically in women, including the signs and symptoms of the disease.
The single greatest risk factor for lung cancer is smoking cigarettes and inhalation of secondhand smoke. This is regardless of gender.
The risk factors for developing lung cancer are similar in both men and women and include:
- family history
- prior medical history of lung cancer or disease
- exposure to asbestos, smoke, or radon
- poor diet
- cigarette smoking
- exposure to secondhand smoke
Smoking or exposure to secondhand smoke remains by and large the biggest and most significant risk factor associated with lung cancer.
However, among nonsmokers, women may be at a higher risk than men. A study published in Seminars of Thoracic and Cardiovascular Surgery found that: "In the U.S. and Europe, approximately 20 percent of women with lung cancer have never smoked versus 2-6 percent of nonsmoking men."
The authors suggested that this difference signaled that there were further differences in the risks and progression of lung cancer in women compared with men.
Men and women also experience very similar symptoms of lung cancer, which can include the following:
- persistent and worsening cough
- ongoing chest pain
- coughing up blood
- shortness of breath
- hoarseness of the voice
- difficulty swallowing
- loss of appetite
- weight loss
- recurrent lung infections, such as pneumonia or bronchitis
Anyone experiencing these symptoms is encouraged to see their doctor to discuss their concerns.
There are several different types of lung cancer. However, there are two in particular that are more common among women.
Small cell lung cancer
Small cell lung cancer is the most aggressive form of lung cancer and it does not present with many symptoms. This means that it advances very quickly and can spread to other parts of the body before a person is aware of any signs or symptoms.
Almost all cases of small cell lung cancer are related to tobacco use.
Adenocarcinoma is usually located outside of the lungs, and it may spread around the body easily.
Adenocarcinoma is a type of non-small cell lung cancer and is the most common form of lung cancer in both women and nonsmokers.
It is often found on the outside of the lung and tends to spread to other parts of the body early on in the disease process.
Both types of lung cancer can progress rapidly, making early diagnosis and treatment crucial.
A diagnosis may be made using scanning and imagery techniques, such as X-rays and MRI scans, and with lung tissue biopsies.
Genetic causes and hormones
It is believed that there may be genetic and hormonal differences or some combination of the two that may explain these differences in lung cancer development and survival in women.
Researchers have identified several genes of interest that might explain why women are affected differently by lung cancer. Some of these genes are inherited, and some of the others are activated by tobacco exposure.
K-ras is a genetic mutation that, if present, may make cancerous tumors grow quicker and be more likely to spread than when it is not present.
Some researchers think that K-ras may make a cancer growth more aggressive when exposed to estrogen, the female sex hormone, as well as other hormones.
Gastric-releasing peptide receptor or GRPR has been associated with cancer cell growth.
Like K-ras, this receptor is more active in women and may be driven by exposure to estrogen.
Epidermal growth factor or EGFR is a protein commonly found in lung cancers. Mutations of the gene that produces EGFR are significantly more common in women than in men.
Some new medications are able to specifically target abnormalities in this protein, so genetic testing for these mutations is essential to find potential candidates for these drugs.
HER2 is a part of the EGFR family that is found in many cases of adenocarcinomas. It is linked with poorer survival in women with lung cancer.
There are estrogen receptors found on the lung cancer cells of both men and women.
Research has shown that in the lab, estrogen encourages the growth of tumor cells and that treatments that block estrogen can help to suppress cancer cell growth.
Researchers have also found that a woman's exposure to estrogen throughout her lifetime may affect her risk for lung cancer. Factors that may affect a woman's level of exposure include:
- number of pregnancies
- age at her first period
- age at menopause
- menstrual cycle details
Radiation therapy may be a recommended treatment for lung cancer, often alongside surgery if possible.
Treatment of lung cancer depends on the stage of the cancer when it is diagnosed.
A small tumor with little to no spread can often be removed surgically. In some cases, the doctor may recommend chemotherapy or radiation therapy to be used alongside surgery to ensure all of the cancerous cells are removed.
If the lung cancer has spread significantly, surgery is not usually an option, and the cancer may be considered to be incurable. A doctor may still recommend radiation therapy to help control complications or to treat pain.
Traditionally, there was no difference in how men and women were treated for lung cancer. However, research exploring the hormonal and genetic differences in lung cancer between the different genders has led to new therapies that may be more effective and appropriate in women than in men.
Drugs that target specific proteins or receptors appear to be more effective in lung cancers of nonsmoking women.
Continued research is needed into these crucial differences that occur between women and men who develop lung cancers, as well as into medications that can target the disease.
Lung cancer has a serious prognosis with the 5-year survival rate only being around 15 percent for stage 3 cancers. However, the rate is around 50 percent in people who are treated early in the disease process before the cancer has a chance to spread.
There is no screening test that will detect early lung cancers, making it important to be careful about avoiding tobacco and secondhand smoke.
Living a healthful lifestyle and avoiding exposure to smoke is the best way for women to reduce their risk of developing lung cancer.