Transcription:
Overview of Lung Cancer

This is Hello Healthy, a Dignity Health Podcast.

Caitlin Whyte: Welcome back. I'm your host, Caitlin Whyte. And today, we have on the show Dr. Murali Dharan. He is a thoracic surgeon and is here to discuss the importance of lung cancer screenings as well as the benefits, risks and symptoms to look out for. So, Dr. Dharan, starting off here, who should be getting screened for lung cancer?

Dr. Murali Dharan: Yeah, that's a very good question to ask because there's a certain population of patients who are at a higher risk of developing lung cancer. And once we understand who these patients are, then we can use resources that are directed towards these patients. So we classify them into category 1 patients and category 2 patients.

And this is all done by the National Cancer Society and the National Cancer Society also had a National Lung Screening Trial. And what they said was category 1 patients are patients who have a history of smoking for a 30-pack-year. What it means is if you smoke one pack a day for one year, that's considered to be a one-pack-year smoking history.

So if you smoke one pack a day for 30 years, that's called a 30-pack-year smoking. So the American Cancer Society recommends screening in patients who are over the age of 55 and have a 30-pack-year smoking history. And if you ask why 30-pack-year? That's considered to be heavy smoking, one pack a year for 30 years, and that's a moderate heavy smoking. And those are the patients who are at risk of getting lung cancer.

The category 2 patients have a family history of smoking. They could have had a brother, a sister, a mother or a father who have lung cancer. And they are a high risk group, not as high as the smoking group. Let's say we have somebody who is 60 years old, she's a female. She does not smoke, has never smoked, but has a brother who died of cancer, that puts her at a slightly higher risk. If she were smoking and had a 30-pack-year smoking history, then she can also be screened. Even if she did smoke for 20 years, she's still considered a relatively high risk. Patients who have exposure to radon, to diesel exhaust fumes, to radiation. So these are again another subset of patients that have a slightly higher risk.

And lastly, you know, there's discussions about secondhand smoke. They could say you could have 55 or a 60-year-old woman coming in and saying, "You know, my dad smoked when I was a child. He smoked all the time. I was around smoke all the time. And in winter, we'd have the windows closed because it was cold. We didn't have a heater. And there was smoke in the air always." So there is an indirect link to cancer, but it's not as significant as in people who have direct exposure to smoke.

Caitlin Whyte: Now that we know who should be getting screened, what is involved with the screening itself?

Dr. Murali Dharan: So the screening actually is a very minimally invasive test. So the screening is a CT scan. It's a low-dose CT scan. It's a test that's done at any facility or hospital that has a CT scan. So it takes a few minutes to get this test done. There is no injections given. There's no medications given. All you need is to go into the CT scanner and you hold your breath for a few seconds and the CT scan does the job. And then you see the results on that on the CT scan.

So what does it show in people who have a likelihood of cancer? So it can show two things, right? It can show an opacity. An opacity is like an abnormality that's not well defined. It is kind of vague, but it's like a little density that you see. And the second type of finding that you can get is a density that's more solid.

So we can look at radiology picture and say this is very dense, this is less dense. If it is less dense, the chance of cancer is much less. If it is very dense, in which case we'd call that a pulmonary nodule, the incidence of cancer is high. And it's high when the density is of a larger size or the nodule is of a larger size. So if it's more than one centimeter in size, the likelihood of cancer increases.

So if you take most people and do a CT scan, you'll find 5-millimeter, 2-millimeter, 3-millimeter nodules. It's not that we need to get worried about it because if you live in the Central Valley, sometimes you can get a fungal infection or a scarring in the lung that can appear as a lung cancer. So these need to be followed up.

So anything that's larger than 1 centimeter needs to get worked up because the larger it is, the greater the chance of it being a cancer. The smaller it is, the less chance of a cancer. So you'll follow up with yearly CT scans. Or if it's over 10 millimeters or 1 centimeter, then we may follow it up depending on the patient's history, either every three months or every six months.

Medicare pays for this. So Medicare has approved the CT scanning as a screening tool and pays for this. And most insurances, if the doctor recommends it, also pay for this. So it's a simple test that's very quick. It's available in almost any part of the United States.

Caitlin Whyte: That's so good to hear that it's pretty accessible. Now, what are some concerning symptoms we should be aware of? You know, we know who should be getting screened, but what are some things that might pop up along the way?

Dr. Murali Dharan: So the symptoms of, uh, lung cancer appear actually late in the disease, meaning that a nodule that's 5 millimeters, 10 millimeters that's on its way to become a lung cancer usually is asymptomatic. That's why we want to pick up a lung cancer with a screening test, because when you pick it up with a screening test, your diagnose this very early on. It's usually stage I or at the most stage II. So the cure rates are high. When it's stage one, the cure rates are much higher than when patients present with symptoms.

So in general, when patients present with symptoms, it's a little late in the course of the disease that they present. Sometimes of course, you can have stage I cancer presenting very early on. You may have a little wheezing or it may be causing an obstruction to the airway and causing pneumonia that persists, doesn't go away or comes back all. Or you can have a bronchitis that's recurrent. It doesn't go away, it comes back. And that could be because there could be a small 1-centimeter tumor that's obstructing the airway. So those cases, they can still be an early lung cancer.

So you have different types of symptoms, but the most common symptom of lung cancer is coughing and a cough that persists, a persistent cough that doesn't go away, you know, you treat it with antibiotics, it still doesn't go away. So any cough that persists over two to three weeks is very concerning.

So if you have a cough that doesn't clear on a week's time, it's time to see your doctor. And they usually would do further testing. In general, the typical tests they would do would be an x-ray. They would also look your history. Sometimes if you have asthma, if you have wheezing problems, you may have cough.

And a lot of times, a smoker has a cough. So it's called a smoker's cough because in smokers, they have extra mucus production, which stagnates in the airways and they get early morning cough. When they wake up, they cough out sputum. So that's a little different from lung cancer. But any cough that's persistent, it doesn't go away or a new cough that comes on that's never been there and you get a cough, that's a warning symptom.

The second is shortness of breath, unexplained, shortness of breath. It can be again another symptom, although nonspecific, it can occur in lung cancer. Very rarely you can get blood when you cough. That is indeed concerning when you have blood when you cough and when you bring out the sputum.

The other symptoms are unexplained loss of weight, unexplained loss of appetite, just not feeling well, kind of feeling fatigued, tiredness. Sometimes hoarseness of the voice, a change in voice that's unexplained, then that persists. So a lot of times you can get bronchitis, your voice gets hoarse, but should get better in a few days, a week or so. But if it doesn't get better, that's the problem. Occasionally, you're going to have pain. Pain in your chest area, in your ribs, in one particular spot, that's kind of annoying, vague, dull aching pain.

So these are typical, you know, symptoms associated with lung cancer, but again, most symptoms associated with lung cancer has to be worked up. And anything that persists for over a week certainly needs to be investigated.

Caitlin Whyte: Now, what are some benefits and risks when it comes to these screenings?

Dr. Murali Dharan: So the benefits of the screening tests, of course, are the fact that you can diagnose these cancers very early on, right? So if you take lung cancer in 2010 to 2012, 2013, if you had five patients come in to my office with lung cancer, let's say they come in with some symptom and we worked them up and let's say all five of them are cancer, at the end of five years, only one of them would be alive. And the reason is because the incidence of the five-year survival, we usually go by five-year survival. If at five years, you're alive after lung cancer, it's very likely that it's cured.

So the chances of five-year survival in all comers of being alive at the end of five years is about 16 to 18%. Now that's improved now with significantly better chemotherapy agents, better radiation, better surgical techniques. So that has improved. But still, if you have symptoms or you come in with advanced stage lung cancer, the overall prognosis is quite poor.

But if you come in with stage I or an early lung cancer that's typically the stage that's found when you do a screening study, like a CT scan, then your chances of survival dramatically improves. So it's almost depending on the type of a cancer, the location of a cancer, it ranges anywhere from 60 to 80%. In favorable lung lesions, it is up to 80%.

So, if all those five patients had early lung cancer that came in because you have a CT scanner, four out of five would be alive at five years. So that's a dramatic improvement in survival from about 16 to 20% to about 70 to 80% at the end of five years. So that's why doing a screening study is so important in these high-risk patient groups.

And it's really painless. It is not a test that's very difficult to do. It's a very simple test. It takes a few minutes to get it done and it can be done pretty much in any reasonable medical center. It certainly can be done in most of the company, in many, many places. It can also be done at an outpatient CT scan department or a CT scan business. You don't have to come to the hospital for it. In a hospital, it is well suited to follow up. If you do have lesion or if you have a nodule, they have the wherewithal to decide what to do, how do we take care of this.

So what does it entail, right? Let's say you find something on the CT scan. Let's say you find a 15-millimeters, a 1.5-centimeter nodule. So what it then entails is a further lookup and a biopsy to see what it exactly is.

So when you said, what are the downsides of screening tests? The downsides are what we call an overdiagnosis, right? We see something, we think it's cancer, we go in and do a biopsy. It comes out as being benign. It's a scar tissue or a fungal infection, but now you ended up doing a procedure on the patient and like anything else, there's always a side effect or a risk or a complication of a procedure. But if you take all comers, that risk is significantly less than the benefit of what you get with lung screening.

So I would say the risks are small. The risks of overdiagnosis are small. And a lot of times you can do other testing to prevent something invasive from going on. So if you do a screening test, you are not sure, you can follow it up with another CT scan in three months or six months. And sometimes these lesions go away. You don't need to do anything else.

Sometimes if you have a suspicion that this is a lung cancer, we do another test called a PET CT scan. A pet CT scan, you inject glucose that's tagged and the glucose is eaten up by these cancer cells and it shows up as a hotspot. So when you see a hotspot or a hypermetabolic area, that's concerning for a lung cancer, you can still work it up.

But I think the downside for not doing something is much higher because the prognosis of lung cancer is one of the worst. If you take most cancers that come in, if you take lung cancer, you take breast cancer, you take colon cancer, you take kidney cancer, the prognosis is worse with lung cancer compared to all these. And that's why I think it's important that you need to do screening and get that taken care of because your prognosis is so much better when you diagnose these cancers early on compared to not doing it. Because if you don't, if you come in advanced advantage, for example, breast cancer or kidney cancer, sometimes the cure rates are still better than lung cancer.

And as you know, lung cancer is the number one leading cause of cancer for men and women in the United States and also the rest of the world. So we have about 135,000 patients that die from lung cancer every year in the United States. And that's the highest volume of deaths from any type of cancer.

Caitlin Whyte: Absolutely. It's so important to catch this as soon as possible. Now, wrapping up here, are there any last bits of information, doctor, that we should know about lung cancer screenings?

Dr. Murali Dharan: Yeah, I think a couple of things that I want people to know is one is cigarette smoking, right? If you look at, uh, cancers, patients who smoke and patients who don't smoke. If you look at it, there's about an 80% incidence of-- if you take lung cancers, a hundred of them come to you, we find that 80 of them probably smoke and about 15 to 20 of them don't smoke.

So you could say, "You know, my grandmother, you know, has been smoking for a60 years and she smoked a pack and a half and she was fine. She did great. She had no problems." Yes. There are some patients who are not prone to lung cancer. So we still can't identify what it is, but a lot of us have genetic mutations. And if you have genetic mutations that can make us prone to lung cancer, then once we start smoking, that accelerates the problem.

So that's why it's important-- and there are many, many mutations that are known, and there are many mutations that are prone for lung cancer. In smokers, it makes them very susceptible to it. So if you look at cigarette smoke, it has about 7,000 chemicals in it. And all of the 7,000 chemicals, 50 of them are called so-called carcinogens or cancer-provoking agents in cigarette smoke. And that's why it's important to avoid smoking.

So if you quit smoking today in about 12 to 24 hours to test these patients, there's already a decrease in carbon monoxide levels in them, right? That's in a very short time. You start seeing the benefits of quitting smoking in a day and every day that you get away from smoking, it makes your lungs better.

There's a lining in the lung called the cilia. And there are certain air sacs in the lung called alveoli and all of these get damaged by the nicotine and smoking. So once you stop, there's a gradual improvement in the function. The cilia starts working better. That's why smokers tend to have more mucus production. They cough a little bit more. They have this early morning cough with mucus. All that starts getting better. And as the days from quitting smoking increase and increase and increase, I think your lung cancer incidence can go down. So I think it's very important to quit smoking. And I think that is the most important thing that you can do for yourself and for your family, if you want to avoid lung cancer, right?

There's not many things that you can avoid. Diabetes, sometimes it's hard to avoid it. Uh, getting a cancer somewhere, sometimes it's hard to avoid. You may get it just because you get older, there's a family history, there's genetic mutations. But one thing you can do to stop is stop smoking and that I would encourage.

Caitlin Whyte: Always important. Well, doctor, thank you so much for your time and for sharing this information with us.

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This has been Hello Healthy, a Dignity Health podcast. I'm Caitlin Whyte. Stay well.