
Lung cancer cell - image courtesy of the LRI EM unit
This entry is part 12 of 22 in the series Science Surgery
Our Science Surgery series answers your cancer science questions.
Janette asked: “Why do never-smokers get lung cancer?”
“It’s a question that often comes up in the clinic,” says Dr Mariam Jamal-Hanjani, an oncologist and clinical researcher specialising in lung cancer at University College London. “And it’s one that researchers have been asking for decades.”
The link between smoking and lung cancer has been known for almost 70 years. It’s the biggest cause of lung cancer in the UK, with around 7 in 10 lung cancers caused by smoking cigarettes. But there’s also a group of people who develop lung cancer and have never lit a cigarette.
“Around 10-15% of the lung cancer patients I see have never smoked,” says Jamal-Hanjani, who’s working on two Cancer Research UK-funded studies. “But we don’t always know why it is that these people get lung cancer.”
According to Jamal-Hanjani, the data suggests that genetics play a role, as well as environmental or occupational exposures.
Spotting DNA differences
When you compare lung cancers in smokers and never-smokers, differences start to emerge. The first of which is the types of lung cancer they develop.
“Smokers can develop all types of lung cancers, although the association is stronger for small cell lung cancer and squamous cell carcinoma, whereas never-smokers are more likely to develop a non small cell lung cancer called lung adenocarcinoma,” says Jamal-Hanjani.
Types of lung cancer
Lung cancer is divided into 2 main groups:
- small cell lung cancer, and
- non small cell lung cancer.
They behave in different ways and respond to treatment differently. Around 9 in 10 lung cancers are non small cell lung cancer.
There are also differences when you look at the DNA inside the tumour cells.
Non-smokers who develop lung cancer are more likely to have cells with a fault in a gene called EGFR. This fault is commonly found in Asian women who had never smoked and developed lung cancer. But according to Jamal-Hanjani, it’s seen in other people too.
“If you’ve never smoked you’re more likely to have a lung cancer that’s driven by a fault in one or potentially more genes,” she says. “And these aren’t necessarily genetic faults that you’re born with, they’re faults that develop during someone’s lifetime.”
These DNA faults can offer up new options for treatment. For example, changes in the EGFR gene can be targeted by drugs like elortinib (Tarceva) and gefitinib (Iressa).
Looking for environmental risks
To understand what might increase someone’s risk of cancer, researchers study large groups of people for many years to look for links between exposure to something and lung cancer.
“These are really tough studies because they need to involve big numbers of people and long periods of follow up. And you need to clearly demonstrate that people who were exposed to something develop cancer, and that there are no other factors that could explain the association.”
To make it easier to exclude other risk factors, scientists will often run ‘case controlled’ studies.
“You might have one person who was exposed to second hand smoke, and then you’ll have another patient within the study who’s matched to that person in every way other than the fact they weren’t exposed to second hand smoke,” says Jamal-Hanjani. “And then you look in big numbers to see if the group of patients who were exposed to smoke were more likely to develop lung cancer.”
Studies like this have shown that being exposed to second hand smoke, for example by living with someone who smokes, can increase a person’s risk of lung cancer by almost a third.
Researchers have also discovered that exposure to asbestos, radon gas or tiny particles that come from diesel exhausts and construction sites can increase someone’s risk of lung cancer. But the individual risks are small.
Staying vigilant
Overall, the risk of developing lung cancer if you’ve never smoked is far lower than if you have or still do. But Jamal-Hanjani says that this shouldn’t lead to a blind sense of security.
“I’ve had patients who had a persistent cough or who were coughing up blood, but believed that because they had never smoked they couldn’t possibly have lung cancer. And it’s not true. There’s still a chance they could develop lung cancer and it not have anything to do with cigarettes. So, people should always seek advice from their doctor if they notice any changes.”
Katie
We’d like to thank Janette for asking this question. If you’d like to ask us something, post a comment below or email sciencesurgery@cancer.org.uk with your question and first name.
- Introducing our Science Surgery series
- Science Surgery: ‘What factors lead to a cell becoming cancerous?’
- Science Surgery: ‘Could more cancers be caused by inherited faulty genes than we now think?’
- Science Surgery: ‘Will cancer ever be cured?’
- Science Surgery: ‘Is the one-size-fits-all treatment approach obsolete?’
- Science Surgery: ‘Does having had cancer make you more likely to develop it again?’
- Science Surgery: ‘What’s being done to use treatments in different types of cancer?’
- Science Surgery: ‘Do we all have potentially cancerous cells in our bodies?’
- Science surgery: “What’s the difference between the words genome, gene and chromosome?”
- Science Surgery: ‘Will cancer ever be eradicated completely?’
- Science Surgery: ‘How quickly do tumours develop?’
- Science Surgery: ‘Why do never-smokers get lung cancer?’
- Science Surgery: ‘Why doesn’t the immune system attack cancer cells?’
- Science Surgery: ‘How do tumours ‘know’ where to spread?’
- Science Surgery: ‘How is skin cancer related to sun exposure?’
- Science Surgery: ‘Does cancer attack every age group?’
- Science Surgery: ‘Why do some cancer treatments stop working after so long?’
- Science Surgery: ‘Does cancer affect the future development of children?’
- Science Surgery: ‘How do cancer cells remain dormant for many years?’
- Science Surgery: ‘Why do some cancers metastasise, but others don’t?’
- Science Surgery: ‘Are benign tumours different from cancerous tumours?’
- Science Surgery: ‘How are children’s cancers different from adults’ cancers?’
Comments
News digest – lung cancer in non-smokers, targeted clinical trials, pancreatic cancer ‘chatter’ and immigration | HealthyVibe May 13, 2019
[…] 1 in 6 people dying of lung cancer in the UK are non-smokers, according to new research from the Royal Society of Medicine. The Guardian covered the new figures, which found that around 6,000 non-smokers in the UK die of lung cancer each year. Experts have suggested that the stigma of smoking has stalled investment in lung cancer research and said it’s time to give lung cancer “the recognition it deserves.” We blogged before about why never-smokers get lung cancer. […]
Carol Smith May 4, 2019
I was diagnosed with adenocarcinoma in August 2016.I have never smoked or lived anywhere that the environment would trigger it .I was put on a clinical trial ,which was 4 cycles of strong chemotherapy followed by 18 months of maintenance chemotherapy. When the tumour began to change I had 10 fractions of radiotherapy which reduced it a little but at the next scan it had doubled in size. I had also been tested for the immunotherapy drug & was found to be 100% positive so that was my next treatment. I had 3 cycles after which the scan showed it had grown 1 cm in each direction.
I have just recently been able to have the tumour & surrounding lymph nodes removed.( the lymph nodes were found to be cancer free) I am now just having the last 2 cycles of Chemotherapy as a precaution but after the next scan hopefully I will be cancer free.
I was told at the beginning that without treatment I would have months left to live. I can’t quite believe that I have now got to the end. I cannot thank the Freeman Hospital in Newcastle enough for the exceptional care & treatment they have given me.
Lung cancer in non-smokers is on the rise, experts say | edition america April 28, 2019
[…] 1 in 6 people dying of lung cancer in the UK are non-smokers, according to new research from the Royal Society of Medicine. The Guardian covered the new figures, which found that around 6,000 non-smokers in the UK die of lung cancer each year. Experts have suggested that the stigma of smoking has stalled investment in lung cancer research and said its time to give lung cancer “the recognition it deserves.” We blogged before about why never-smokers get lung cancer. […]
Lung cancer in non-smokers is on the rise, experts say | Londoner News April 28, 2019
[…] 1 in 6 people dying of lung cancer in the UK are non-smokers, according to new research from the Royal Society of Medicine. The Guardian covered the new figures, which found that around 6,000 non-smokers in the UK die of lung cancer each year. Experts have suggested that the stigma of smoking has stalled investment in lung cancer research and said its time to give lung cancer “the recognition it deserves.” We blogged before about why never-smokers get lung cancer. […]
Lung cancer in non-smokers is on the rise, experts say | The Daily Cambridge April 28, 2019
[…] 1 in 6 people dying of lung cancer in the UK are non-smokers, according to new research from the Royal Society of Medicine. The Guardian covered the new figures, which found that around 6,000 non-smokers in the UK die of lung cancer each year. Experts have suggested that the stigma of smoking has stalled investment in lung cancer research and said its time to give lung cancer “the recognition it deserves.” We blogged before about why never-smokers get lung cancer. […]
Lung cancer in non-smokers is on the rise, experts say | francenews7 April 28, 2019
[…] 1 in 6 people dying of lung cancer in the UK are non-smokers, according to new research from the Royal Society of Medicine. The Guardian covered the new figures, which found that around 6,000 non-smokers in the UK die of lung cancer each year. Experts have suggested that the stigma of smoking has stalled investment in lung cancer research and said its time to give lung cancer “the recognition it deserves.” We blogged before about why never-smokers get lung cancer. […]
Lung cancer in non-smokers is on the rise, experts say | Germany Latest News April 28, 2019
[…] 1 in 6 people dying of lung cancer in the UK are non-smokers, according to new research from the Royal Society of Medicine. The Guardian covered the new figures, which found that around 6,000 non-smokers in the UK die of lung cancer each year. Experts have suggested that the stigma of smoking has stalled investment in lung cancer research and said its time to give lung cancer “the recognition it deserves.” We blogged before about why never-smokers get lung cancer. […]
Lung cancer in non-smokers is on the rise, experts say | irelandnow April 28, 2019
[…] 1 in 6 people dying of lung cancer in the UK are non-smokers, according to new research from the Royal Society of Medicine. The Guardian covered the new figures, which found that around 6,000 non-smokers in the UK die of lung cancer each year. Experts have suggested that the stigma of smoking has stalled investment in lung cancer research and said its time to give lung cancer “the recognition it deserves.” We blogged before about why never-smokers get lung cancer. […]
Lung cancer in non-smokers is on the rise, experts say | texas 24 news April 28, 2019
[…] 1 in 6 people dying of lung cancer in the UK are non-smokers, according to new research from the Royal Society of Medicine. The Guardian covered the new figures, which found that around 6,000 non-smokers in the UK die of lung cancer each year. Experts have suggested that the stigma of smoking has stalled investment in lung cancer research and said its time to give lung cancer “the recognition it deserves.” We blogged before about why never-smokers get lung cancer. […]
Lung cancer in non-smokers is on the rise, experts say | Florida Report Daily April 28, 2019
[…] 1 in 6 people dying of lung cancer in the UK are non-smokers, according to new research from the Royal Society of Medicine. The Guardian covered the new figures, which found that around 6,000 non-smokers in the UK die of lung cancer each year. Experts have suggested that the stigma of smoking has stalled investment in lung cancer research and said its time to give lung cancer “the recognition it deserves.” We blogged before about why never-smokers get lung cancer. […]
Lung cancer in non-smokers is on the rise, experts say | United Journalism April 28, 2019
[…] 1 in 6 people dying of lung cancer in the UK are non-smokers, according to new research from the Royal Society of Medicine. The Guardian covered the new figures, which found that around 6,000 non-smokers in the UK die of lung cancer each year. Experts have suggested that the stigma of smoking has stalled investment in lung cancer research and said its time to give lung cancer “the recognition it deserves.” We blogged before about why never-smokers get lung cancer. […]
Lung cancer in non-smokers is on the rise, experts say - news wireline April 28, 2019
[…] 1 in 6 people dying of lung cancer in the UK are non-smokers, according to new research from the Royal Society of Medicine. The Guardian covered the new figures, which found that around 6,000 non-smokers in the UK die of lung cancer each year. Experts have suggested that the stigma of smoking has stalled investment in lung cancer research and said its time to give lung cancer “the recognition it deserves.” We blogged before about why never-smokers get lung cancer. […]
Lung cancer in non-smokers is on the rise, experts say | britain today news April 28, 2019
[…] 1 in 6 people dying of lung cancer in the UK are non-smokers, according to new research from the Royal Society of Medicine. The Guardian covered the new figures, which found that around 6,000 non-smokers in the UK die of lung cancer each year. Experts have suggested that the stigma of smoking has stalled investment in lung cancer research and said its time to give lung cancer “the recognition it deserves.” We blogged before about why never-smokers get lung cancer. […]
Lung cancer in non-smokers is on the rise, experts say | Evening Washington April 28, 2019
[…] 1 in 6 people dying of lung cancer in the UK are non-smokers, according to new research from the Royal Society of Medicine. The Guardian covered the new figures, which found that around 6,000 non-smokers in the UK die of lung cancer each year. Experts have suggested that the stigma of smoking has stalled investment in lung cancer research and said its time to give lung cancer “the recognition it deserves.” We blogged before about why never-smokers get lung cancer. […]
Terry Kavanagh April 11, 2019
Good site. A lifetime non-smoker I was diagnosed with lung cancer and had half of my left lung removed. Later I was told by my oncologist that cancers can be identified and mine was a smokers cancer. Squamous cell. Survive it now over 30 years from diagnosis.
A M Galloway April 10, 2019
Excellent, thank you. As a retired doctor I find your web site excellent. Keep it coming I know it takes a lot of work to keep it up to date and informative.
Katie Roberts March 14, 2019
Hi Issidoros,
Thanks for your questions. We’ve written about what can lead to a cell becoming cancerous for a previous science surgery (https://scienceblog.cancerresearchuk.org/2017/05/26/science-surgery-what-factors-lead-to-a-cell-becoming-cancerous/). Some viruses have been linked to causing damage that could lead to cancer, such as the human papillomavirus (HPV) and cervical cancer. And while we still don’t understand everything that could cause a cell to become cancerous, our scientists are looking at unique ‘fingerprints’ in a cell’s DNA to try and get a better picture (https://scienceblog.cancerresearchuk.org/2017/04/18/discovering-unknown-causes-of-cancer-through-fingerprints-in-dna/).
To answer your second question, scientists are working to develop treatments that can take immune cells from a patient and then alter them in the lab to make them better at killing cancer cells before returning them into the bloodstream. This innovative treatment is called CAR T cell therapy, we’ve written more about it here (https://scienceblog.cancerresearchuk.org/2018/10/05/cutting-edge-car-t-cell-immunotherapy-approved-in-england-but-is-the-nhs-ready/).
Best wishes,
Katie, Cancer Research UK
Issidoros Nicholas Lemanis March 12, 2019
Excellent explanation to various questions about cancer research and treatment. I am cancer patient and also cancer research supporter with monthly standing order. May I ask 2 questions. First is. Could damage to our cells get created by nano-viruses? Second is. Can we extract immune cells from a cancer patient then multiply them in lab and inject back to the patient to kill the cancer cells? Many thanks and please add me to your list to receive your news. With kind regards Issidoros N. Lemanis(Mr)
Opinion: ‘NHS targeted lung health checks are another reason to be positive about lung cancer’ – Trending Headline News February 27, 2019
[…] also need to develop ways to spot the disease early when it occurs in non-smokers – a group of thousands who often feel additionally marginalised by the disease’s tragic […]
Rita Lucas February 19, 2019
I think this is a very informative site and has answered/clarified the many aspects of cancers questions.
Opinion: ‘NHS targeted lung health checks are another reason to be positive about lung cancer’ – Cancer News February 15, 2019
[…] also need to develop ways to spot the disease early when it occurs in non-smokers – a group of thousands who often feel additionally marginalised by the disease’s tragic […]
Robin Boultwood January 7, 2019
My wife died from lung cancer 3.5 years ago, she was told it was not smoking related although she had smoked, but not for about 45 years. One thing she did do though was to use hair spray in our shower room which was quite small, I often wonder if this might have been a factor?
Mrs Patricia Summers January 5, 2019
I would love to think that one day they would find away of knowing the real reason what
really is the cause of people having cancer even on animals having that dreadful disease which kills them & people.
You are wonderful people that are so caring what would we do without you my Husband & I try to do all the right things & eat the best of foods..
Yours
Sincerely
Mrs Patricia Summers.
Lauraine January 5, 2019
Hi I read the story on lung cancer in non smokers I was a non smoker but I developed lung cancer in 2003 which was course by secondary breast cancer also I did live with people who smoked. Why do some people who had lung cancer end up with breathing problems I have to use a inhaler.
News digest – lung cancer in non-smokers, targeted clinical trials, pancreatic cancer ‘chatter’ and immigration – My Blog May 15, 2019
[…] 1 in 6 people dying of lung cancer in the UK are non-smokers, according to new research from the Royal Society of Medicine. The Guardian covered the new figures, which found that around 6,000 non-smokers in the UK die of lung cancer each year. Experts have suggested that the stigma of smoking has stalled investment in lung cancer research and said it’s time to give lung cancer “the recognition it deserves.” We blogged before about why never-smokers get lung cancer. […]