Auntie Liu is 48 years old, an accountant in the company, usually has a very regular routine and often goes out for square dancing. The company’s main business is to provide a wide range of products and services to its customers. The first time I saw her, I saw an abnormal mass in her upper right lung, and she was diagnosed with stage III lung adenocarcinoma.
After a few visits to the clinic, the cough didn’t get better. The company’s main goal is to provide the best possible service to its customers.
In life, if you hear that someone has lung cancer, it is always associated with “smoking”. But in recent years, more and more women are being screened for lung cancer who have no family history, have never smoked, take care of themselves, and rarely even cook.
This is mind-boggling, but there are more cases and data that show that lung cancer has moved beyond “male smokers” to “non-smoking women”.
Lung cancer incidence doubles in Chinese women in 15 years
Lung cancer is the number one killer of all malignancies.
In 2014, there were 782,000 new cases of lung cancer in China, and 626,000 deaths in the same year. In general, the incidence and mortality rates of lung cancer are about twice as high for men as for women. This is related to the higher smoking rate among men in China (52.1%).
And, among young patients 30-44 years old, lung cancer in women is almost as close as in men in the same age group (1.1 million vs. 1.44 million). Similar results were seen in young women under 30 years of age, which is very different from men over 45 years of age who had twice as many lung cancers as women.
But between 2000 and 2014, the incidence of lung cancer in women nearly doubled from 27.77 per 100,000 to 51.31 per 100,000. And the number of women who smoke has decreased to 2.7%, and 25 times as many women never smoke as do.
The situation is similar not only in China, but also in developed countries such as East Asia and Europe and the US. In the United States, the incidence of lung cancer in women under 50 has begun to exceed that of young men, which may be related to the increase in smoking among young women in the United States.
But why is the incidence of lung cancer increasing in China, when the rate of smoking among women has been decreasing?
At the end of the last century, a retrospective analysis of causes of death in a million people in China, published in the leading British Medical Journal (BMJ), found that 82% of men who died of lung cancer in China were smokers.
But among women it was the exact opposite – 61% of the women who died did not smoke! In rural areas where there are few women who smoke, non-smoking women even account for nearly 80% of lung cancer deaths.
Looking at lung cancer death rates for all populations, it’s strikingly consistent: smokers are three times more likely to die from lung cancer than nonsmokers, regardless of gender.
So even if the risk is only 1/3 for non-smoking women, behind a population base that is tens of times different, we see that non-smoking women get lung cancer a lot more than smoking women!
Conversely, men don’t have this problem because there are already more smokers than non-smokers, and multiply that by 3 times the risk, and it’s like a big snowball rolling even bigger, and more people end up dying from lung cancer than smokers (82.5%).
But that algorithm doesn’t quite work when you compare our women to Western European countries with high female smoking rates.
For example, in France, the female smoking rate is as high as 30%. This corresponds to similar lung cancer rates – our women have even slightly higher age-standardized lung cancer rates than French women (22.8 vs 22.5 per 100,000).
This suggests that there are factors other than smoking that have a greater impact on Chinese women.
China has the worst problem with secondhand smoke, and how deeply does it affect lung cancer in women?
China has the worst secondhand smoke problem in the world, with 316 million people smoking and 740 million nonsmokers inhaling secondhand smoke, and 100,000 deaths from secondhand smoke each year.
Japanese studies have also demonstrated that among non-smokers, those who inhaled secondhand smoke in their homes during adulthood had 1.3 times the risk of lung cancer than those who did not inhale secondhand smoke.
So secondhand smoke is indeed one of the killers of lung cancer in nonsmokers.
However, the contribution of secondhand smoke to lung cancer in women is not considered high. The study found that only 11% of lung cancers in non-smoking women in this country were explicitly linked to secondhand smoke from husbands and workplaces. In the remaining 89%, there are other risk factors lurking.
At this point, many of you can’t help but answer: kitchen fumes, right?
Coal burning is a Class 1 carcinogen, more harmful to women than grease smoke
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With all the media publicity over the years, the dangers of kitchen fumes have become a household name. But there’s a question mark over how closely it is linked to lung cancer in women.
Most studies have found that the various high-temperature cooking methods commonly used in Chinese food (frying, deep-frying, stir-frying) increase the risk of lung cancer in women who have never smoked. For example, among non-smoking women in Shanghai, those who deep-fried more than once a week, stir-fried more than seven times, and cooked with very heavy fumes had a risk of lung cancer that was more than one times higher than other women.
And a study of Chinese women in Singapore came to a different conclusion: smoking women had a more than 1-fold increased risk of lung cancer if they stir-fried every day (and up to 4-fold if they stir-fried meat or used unsaturated oils every day), while nonsmoking women had no risk of lung cancer related to stir-frying.
In light of these results, cooking fumes are classified by the World Health Organization as a “class 2A” carcinogen, meaning they are likely to cause cancer, but there is limited evidence of carcinogenicity in humans. Firewood smoke from burning wood for cooking in rural areas also falls into category 2A.
Yunnan Xuanwei is rich in coal, where women have the highest lung cancer mortality rate in the country!
In fact, a more dangerous indoor pollutant than oil smoke is soot from burning coal, which is a Class 1 carcinogen with strong evidence of carcinogenicity in humans.
An example of this is Xuanwei County, Yunnan Province, which is rich in coal resources. The smoking rate here is 90% for men and only 1% for women, (the ratio of men to women in the kitchen is the opposite of the smoking rate). But the local female lung cancer mortality rate is among the highest in the country.
Surveys show that 73% of Xuanwei people use bituminous coal as fuel, and the lung cancer mortality rate for these people is about 500/100,000 regardless of gender, whether they smoke or cook. Even the effects of smoking seem insignificant in the face of high levels of airborne carcinogens. Among those who use anthracite coal, only 4.7/100,000 are women (all non-smokers). This means that 99% of women would have been free of lung cancer if they had not used anthracite.
Think about it, this is how Xuanwei women live every day: poor quality kitchen smoke, long hours of coal cooking, and inhaling secondhand smoke from their husbands. …… How can lung cancer rates not be high?
Nowadays, with the improvement of living standards, it is rare for families to use honeycomb coal and briquettes. But in the northern and western rural areas of China, winter heating is still dominated by coal-fired, and many old rural women have respiratory problems.
So good indoor ventilation, using clean fuels and range hoods, and cooking with minimal frying and stir-frying can really help keep lung cancer away for many people, especially women.
But outside of lifestyle habits, there are two other “killers” that lurk in the air we breathe all the time.
Atmospheric pollution and radon gas also need to be careful, and exercise as little as possible on hazy days!
The first one is a new one.
Recently, heavy pollution has once again emerged in the north of China, which has been jokingly referred to by netizens as the 25th season – the “standing haze”.
In 2013, the World Health Organization listed “outdoor air pollution” as a Class 1 carcinogen, the same level as smoking and soot. 252,000 of the world’s lung cancer deaths in 2016 were related to air pollution. In 2010 alone, 140,000 people died of lung cancer from air pollution in China, accounting for more than half of all deaths worldwide.
Each 10 μg/m increase in PM 2.5 concentrations increases the risk of lung cancer for non-smoking women by 37%. Higher rates of lung adenocarcinoma have also been shown to be linked to atmospheric pollution, as the small particles of PM 2.5 are more likely to enter deeper into the alveoli.
A recent Canadian study found that lifetime PM 2.5 exposure concentrations were significantly higher in non-smoking women with lung cancer than in smoking women. If the air quality was poor during childhood, moving to a place with good air when you grow up does not eliminate the previous cumulative risk.
We are responsible for your lungs by wearing special anti-haze masks on hazy days and minimizing going out and exercising outdoors.
In addition to visible haze, there is also an invisible invisible killer around us – radon.
Radon gas is a radioactive inert gas that exists in the natural environment and is also a class 1 carcinogen. It is colorless and odorless, originally under the ground, but can enter the air through cracks in the foundation, pipes or gaps such as electrical wires.
In outdoor, the concentration of radon is almost negligible; however, indoors, the concentration of radon gas is often related to the proximity to the ground. For example, in the United States, the radon level in homes is often not low due to the house construction near the ground, especially in basements. Therefore, radon becomes the second biggest killer of lung cancer in the United States, second only to smoking.
In China, the radon level on the first floor of single-story homes or multi-story homes is often higher. For every 100 Bq/m³ increase in radon concentration, the risk of lung cancer will increase by 32% after 30 years of residence, and the risk is the same for women and men.
Even in natural high radon areas, soil radon only slightly affects floors below the third floor, and the radon level in daily living rooms is not high. Since most of our residents live in high-rise buildings and the first floor is mostly elevated, the effect of radon gas on non-smoking lung cancer will not be that great.
In addition, although granite and concrete also contain radon, in most cases, the level of radon they release is very low. People do not need to worry too much. If you are really not sure, you can ask a professional institution to conduct a test (China’s regulation is no more than 400 Bq/m³).
Lung cancer in women is “gentler” than in men, early screening is key
Lung cancer in women is both unfortunate and fortunate because it is not as aggressive as lung cancer in men.
At all stages of lung cancer, regardless of clinical stage, histologic type, or smoking status, female patients are better treated than men and have significantly higher survival rates than men. In particular, most female lung adenocarcinomas have genetic mutations such as EGFR, ALK, and HER2, and are better suited to targeted drugs that target these mutations. In contrast, squamous cancers caused by smoking in men lack these mutations and are difficult to treat with targeted therapy.
Lastly, I want to tell you that despite the rise in lung cancer in non-smoking women, tobacco is still the number one killer of lung cancer in China. The risk of lung cancer will only increase, not decrease, as tobacco and other factors “gang up” on us, and the fight against smoking is still urgent.
In addition to staying away from secondhand smoke, coal burning, oil smoke, and air pollution, the most important thing that non-smoking women need to do is to get screened early.
While many people take annual checkups, the package usually only includes a chest X-ray, which is basically useless for early lung cancer screening. If the tumor is large enough to be seen on an X-ray, it’s too late.
For truly early detection of lung cancer, low-dose spiral CT is the only means. It is recommended that people over the age of 50 who are at high risk (smokers, passive smokers or have a family history of lung cancer, etc.) get it done once a year. The cost is a little higher, but someday in the future, you may be thankful that you had this test done.
Of course, if you are not at high risk, but are over 45 years old, live in a place with a lot of air pollution, and are concerned about your risk of lung cancer, you might also consider getting a low-dose spiral CT and then getting regular screenings as recommended by your doctor.
I hope that every woman in China can stay healthy and breathe freely in clean air.