Mesothelioma Diagnosis and Treatment

M. D. Anderson Cancer Center
Cancer Newsline Audio Podcast Series
Date: April 27, 2009
Duration: 0 / 14:13

Return to Cancer Newsline

Host Lisa Garvin:

Welcome to Cancer Newsline, a weekly podcast series from The University of Texas M. D. Anderson Cancer Center. Cancer Newsline helps you stay current with the news on cancer research, diagnosis, treatment, and prevention, providing the latest information on reducing your family’s cancer risk. I’m your host, Lisa Garvin. Today, we’re talking with Anne Tsao, M.D., she’s an assistant professor in the Department of Thoracic Head and Neck Medical Oncology, here at M. D. Anderson. Welcome, Dr. Tsao.

Anne Tsao, M.D.:

Thank you so much for having me.

Garvin:

Let’s talk about mesothelioma first, as a disease. Can you describe mesothelioma?

Dr. Tsao:

Yes, it’s a disease that originates from the lining of the lung, what we call the pleura. And, this is a disease which is most commonly associated with asbestos exposure. And, it can unfortunately take between 20-40 years to develop; the median is usually about 32 years from time of exposure.

Garvin:

We know that a lot of people contracted it during World War II, working in war time industries and manufacturing plants and so forth and the belief was that mesothelioma cases would spike and then start to go down as we gotten rid of asbestos in manufacturing and so forth. What are the trends now?

Dr. Tsao:

Back in the late 1960’s, early 1970’s the United States government did induce some bans on using asbestos as insulation material. Prior to that, most of the people who were exposed tended to be pipe fitters, people who worked in construction, people who worked in the military and certainly, since that time the incidence was assumed to have peaked in 2005 and then go down in the United States. However, with the advent of 911 in New York City, there is a concern that we may see an additional spike. And, indeed there’s a registry of all the first responders in New York City that came, who have now developed some lung disease and the concern is that they need close monitoring just in case they develop some asbestos related diseases later.

Garvin:

Now asbestos, these little fibers, they settle in the lungs. What is the genesis of the disease from the asbestos to the disease?

Dr. Tsao:

Yes, so that is a little bit less clear. The thought is that it may induce some type of inflammatory reaction that over time develops into frank carcinogenesis from the lining of the lung. But, the exact molecular pathway has not been elucidated yet, which is why this is such a difficult disease to treat. In addition to asbestos though, there is some other potential ideologic agents that are a little controversial, one of which is SV40, which is a virus that was thought to contaminate some polio vaccines back in the 1940’s. That has been a little controversial but it’s known that in the laboratory, at least, with infection of certain pleura cells that you can develop Mesothelioma in the laboratory with SV40.

Garvin:

Now, I guess there would be really no way of screening. Say, you’ve got, like my grandfather he may have worked building planes for World War II and he probably has inhaled some asbestos but there really is no screening method. I mean, are they ever discovered before it becomes malignant and grows?

Dr. Tsao:

That’s correct. And this is again part of the problem because it tends to be more of a rare disease; it affects about three thousand people in the United States every year. And so, the natural biology is not very well elucidated. For instance, if you have known exposure, so far, there is no screening methodology such as a chest X-ray yearly, or a chest CT. There are, however, developments in technology and I’ll mention one of them which is a blood test, well I’ll mention two blood tests, one is called serum-soluble mesothelin-related peptide (SMRP) and this actually can detect whether or not a patient who has mesothelioma after they have surgery, if they have an elevated level of SMRP in their blood before surgery, you can see it actually go down to nothing after the surgical resection and when it recurs, you can see it begin to rise again. This is not FDA approved yet. The other study that was just published in the New England Journal of Medicine recently was something called serum osteopontin, and that was discovered in certain people exposed to asbestos to predict that higher levels meant that you were more likely to develop mesothelioma later. However, we haven’t adopted that as a screening method yet because we don’t quite know how to use it.

Garvin:

And so most of your patients, I guess, are probably largely men and probably in their 50s, 60s, 70s, in age?

Dr. Tsao:

Yes. So the usual instances in terms of ratio of men to women, is about three to one. But, it used to be that we would see a lot of people in their 60s and 70s but unfortunately, of late, we’re seeing more people in their 40s and 50s. The reason is that as children they’re exposed to asbestos fibers that clung to their parent’s clothing when they brought it home and if they were washing clothes or were in the house, they developed their exposure to the asbestos.

Garvin:

I know we recently did a story for CancerWise about a fellow who had not worked in any sort of industry, he had maybe renovated a couple of houses but he had mesothelioma. Does asbestos, it’s a naturally occurring material, is it not?

Dr. Tsao:

That is correct, but we have often used it as insulation in certain buildings as well and so he may have potentially lived in an older building and not quite known it. Or potentially, I had one patient who taught at a school which had known asbestos used as insulation as part of the building and unfortunately, there was a few instances of mesothelioma in the teachers that worked at that school.

Garvin:

What is the prognosis for people with malignant pleura mesothelioma?

Dr. Tsao:

Unfortunately, it’s a very difficult disease to treat and if you cannot do multimodality therapy, meaning, if you cannot do surgery, radiation and chemotherapy or potentially now these new biologic agents, the incidence of cure is not there. So, the median survival for someone who cannot have definitive or curative intent treatment is roughly around nine months. In a patient who can get surgery, usually those patients will need to go through very intensive treatment and even then, unfortunately, the median survival can still only range between fifteen to seventeen months.

Garvin:

But it sounds like there are exciting things on the horizon. As you said, I believe you said that standard treatment would be surgery followed by radiation and/or chemo? Or, what is the standard line of care?

Dr. Tsao:

Yes. So, the standard of care per say for anyone who has very limited or early stage disease, meaning it has not spread to the lymph nodes in the center of the chest, and has really stayed contained within the pleura of the chest, on one side. Those patients can potentially get surgery and then usually they get radiation afterwards and often times now, medical oncologists will give adjuvant chemotherapy. We’ve done clinical trials looking at giving chemotherapy ahead of time, before surgery, and then followed by radiation and in some instances that would be appropriate.

Unfortunately though, our trials have not demonstrated on a wide-scale level that this has benefit for all patients with mesothelioma. So now we’ve designed trials to incorporate the novel targeted therapies into this sort of a setting.

Garvin:

You said you were very excited about a drug called Dasatinib

Dr. Tsao:

Yes, actually we identified that SAR kinase, which is a protein that controls cell cycle growth proliferation and is instrumental in some of the other growth signaling pathways that it’s up regulated in mesothelioma. And Dasatinib, which targets SAR kinase actually has an anti-tumor effect in the laboratory. So, we actually have a clinical trial designed to incorporate this, it’s the first of its kind in the world, incorporating it in the new adjuvant setting, meaning before surgery in our patients.

Garvin:

And that’s with the intent to shrink the tumor for better surgical outcomes?

Dr. Tsao:

Well, the intent is to see if it can make the tumor control the tumor growth. And so, the way the trial is designed is to almost test sensitivity. So our patients, when they come in, they will get what we call the staging procedure or extended surgical staging and this is critical because if a patient already has spread of disease to the lymph nodes and the center of the chest or into the abdomen they should not be receiving a surgical procedure because that will make them very likely to have it return very quickly. And, so those patients should not receive surgery. But we will do that procedure and we’re able to harvest certain tumor tissue that we can test for and use as a baseline for the molecular analysis of SAR kinase. And then they get the four weeks of the oral pill, the Dasatinib, and then they get the surgery and we’re able to look at their post-treatment, post four week Dasatinib treatment, and look at their tumor tissue and see if they’ve had molecular modification of that protein. And, we also will look at whether or not radiographically they have a response by CT scan or PET CT, and then those patients that get either a radiographic response or a molecular response they get the drug for free for two years after their surgery, radiation and chemo.

Garvin:

Do you have enough data to…, is it a Phase I trial?

Dr. Tsao:

It is a Phase I trial. It’s being supported by the Department of Defense and in our first ten patients we’ve actually had two that have actually had shrinkage of their tumor …

Garvin:

Wonderful!

Dr. Tsao:

… after only four weeks of the pill.

Garvin:

Wonderful, so it sounds quite promising.

Dr. Tsao:

Yes, it’s very exciting.

Garvin:

And it sounds like targeted and personalized therapy might be the way to go. I know it’s true for a lot of cancers but possibly for mesothelioma as well.

Dr. Tsao:

That is definitely the hope. We know that, with the grim prognosis with our current treatment modalities, we need to make a breakthrough in another way and I do believe that systemic therapy with targeted agents is the way to go.

Garvin:

Of course, we always say at M. D. Anderson, the mantra is early detection is best but it sounds that it’s a pretty rare occurrence with mesothelioma.

Dr. Tsao:

Very true, often times, patients will be seen by their primary care physician and they often times have just a little bit of fluid in their lung and they’re treated with antibiotics, they’re followed a few months down the line and unfortunately this continues until all of a sudden they’re found to have this very large tumor surrounding their lung. And often times, in those situations it becomes almost too late to do a surgery.

Garvin:

Are there any symptoms? And, if there are symptoms do they mimic that of lung cancer?

Dr. Tsao:

There are in many ways similar to lung cancer, the only main difference is you’re more likely to develop chest pain, or what the patient would perceive as chest pain simply because this tumor is from the lining of the lung and it can often press on or grow outward into the chest wall. So they may be more likely to develop chest wall pain sooner than a lung cancer patient would, however, some of the other symptoms are shortness of breath, cough are almost identical to what a lung cancer patient might develop.

Garvin:

Now can mesothelioma be picked up on a chest X-ray like lung cancer?

Dr. Tsao:

When it becomes fairly sizeable, yes, but more often than not, a patient who has early stage disease will be found to have a pleural effusion or water in the lung and that can definitely be picked up on an X-ray. The problem is that, that often has a wide differential; it could mean pneumonia, it could mean lung cancer, it could mean metastatic cancer from another area. So, this is why it’s important to raise awareness of mesothelioma to include that as part of the differential.

Garvin:

And while we’re talking about awareness of mesothelioma, and this is slightly controversial. A lot of what you see when you Google mesothelioma on the internet or on TV commercials, you see lawyers actively seeking mesothelioma patients to get some sort of remuneration for their disease. Does that concern you as a health professional?

Dr. Tsao:

Well, I think what would concern me certainly would be if they promised or provided information that was not reviewed by a certified physician. Um, I’ve seen many of those websites. And I do think that on the one hand, it is very important for a mesothelioma patient who has a known exposure to asbestos from a company, the military, or from a known source, that they receive compensation to help offset the cost of their medical care. So, on the one hand I do think that it is important for legal recourse to be a part of a patient’s journey when they do develop mesothelioma. On the other hand, I think that there’s always some caution that I have that sometimes on the websites, if they are not being presented by a medical professional, that there may be misinformation that’s there about their disease.

Garvin:

So people need to be careful and talk to their healthcare professional?

Dr. Tsao:

Absolutely. They should know that in almost all of the states in the US you do have a statute of limitations on when you can file for a lawsuit; and I believe in the state of Texas it’s either one or two years from time of diagnosis.

Garvin:

So, with mesothelioma, because you have surgical intervention, you’ve got radiological intervention, and chemical intervention, it sounds like it’s very important to come to a multi-disciplinary center like M. D. Anderson for treatment?

Garvin:

So, with mesothelioma, because you have surgical intervention, you’ve got radiological intervention, and chemical intervention, it sounds like it’s very important to come to a multi-disciplinary center like M. D. Anderson for treatment?

Dr. Tsao:

Oh, absolutely. I would encourage anyone who has a diagnosis of mesothelioma to definitely seek a major cancer center, that, and you can look these up on the internet that has a program specifically designed for mesothelioma. I would encourage any patient to consider a clinical study that gives you a little bit more than the standard of care.

Garvin:

Great, I think that that covers it but do you have any final parting thoughts for the audience?

Dr. Tsao:

No, thank you so much for inviting me. It’s a very important disease that needs advocates and so we are certainly grateful that you were interested in highlighting the program.

Garvin:

Great, thank you Dr. Tsao for being with us today.

Dr. Tsao:

Thank you.

Garvin:

If you have questions about anything you’ve heard today, on Cancer Newsline, contact askMDAnderson at 1-877-MDA-6789 or online at www.mdanderson.org/ask. Thank you for listening to this episode of Cancer Newsline, tune in next week for the next podcast in our series.

Return to Cancer Newsline