New Discoveries Provide Hope For Better Treatment Of Deadly Lung Cancer

Asbestos has got lots of negative publicity. The discovery that it is linked to lung cancer has caused practically total ban of this material from industrial use.  But what exactly is the problem and how common it is? There are several misconceptions here that this article aims to address.

Exposure to asbestos is a serious health hazard

Asbestos is a natural fibrous material. In the form of dust, it can easily be inhaled. When this happens, the fibers precipitate on the surface of lungs and stay there forever, since asbestos is insoluble and cannot be removed from the body. Obviously, construction workers are the most exposed part of population since in not so distant part many of them were dealing with asbestos on the daily basis. But most of us have also been in contact with this harmful material since many older building still contain plenty of asbestos.

Asbestos rarely causes immediate serious problems. Intensive or prolonged exposure to the material can cause asbestosis – a chronic inflammatory condition characterized by shortness of breath and even respiratory failure in the advanced cases. But major trouble with asbestos (and the major reason it is not in use anymore) is its link with lung malignancies.

Asbestos causes lung mesothelioma

Contrary to the common opinion, asbestos is rarely causing lung cancer. The type of tumor triggered by asbestos is called malignant mesothelioma. Usually this disease happens in the lungs (and thus become known as pleural mesothelioma) but can also occur in other parts of the body such as linings of the stomach. The difference between lung cancer and lung mesothelioma is in the site of origin – the cells that become cancerous and produce tumor come from different tissues. Lung cancer originates from the cells of lungs themselves while pleural mesothelioma begins from the cells of mesothelium, the linings of the lung. The particles of asbestos are large in size and can’t go deep into lungs thus causing the problems on the surface of this organ rather than in the deep layers of lung tissues.

Both lung cancer and lung mesothelioma have similar symptoms. Both are very aggressive and deadly diseases that tend to develop quickly. For both we have very few effective methods of treatment and management. But their mechanisms are different. This means that drugs that will be eventually developed for these malignancies will have to work differently.

Popular media led us to believe that asbestos-caused malignancies are very common. In fact, this is not entirely correct. Lung mesothelioma is a relatively rare disease. Around 3,000 cases of this disease are registered in the US each year. For comparison, around 200,000 lung cancer cases happen each year among Americans.

Why lung mesothelioma is a major concern?

Even though the frequency of asbestos-linked lung mesothelioma is relatively low, the number of incidences is growing. The reason for this is that disease can have an incredibly long incubation period of 20 years or even more. Some patients have developed cancer 50 years after asbestos exposure. Those insulators workers who were exposed to asbestos decades ago in their twenties can get disease now when they are already retired.

Unfortunately, like in the case of usual lung cancer, the early detection of pleural mesothelioma represents a significant problem. We simply have no effective methods of doing so. CT scan is the only way of catching the disease early. The scans should be performed at regular intervals, ideally every 6 months or so. Needless to say, this is an expensive option that is not available to everyone. Also, we have nothing to prevent the development of disease, and people with the known exposure to asbestos can do very little to reduce their chances of getting cancer.

Lung Mesothelioma Is Incredibly Difficult To Treat

Like other lung tumors, pleural mesothelioma presents a major challenge for the oncologists. Apart from classical approaches based on radical surgery, aggressive chemotherapy and irradiation of lungs, there are very little therapeutic options. The fact that most patients get diagnosed at late stage of this cancer doesn’t help in improving their chances of survival.

Recent relative progress in the treatment of cancer left lung malignancies on the side line of progress. New targeted therapeutics allow to improve the survival of breast cancer patients by almost three times and give many women many additional years of life. The same or similar drugs extend the life of patients with lung mesothelioma by few months only.

New therapeutic approaches offer hope

Not everything is doom and gloom though. Although slowly, new drugs do get developed. Each new treatment allows to extend the median survival of lung mesothelioma patients by few months. If more such drugs developed, a significant progress can be achieved. A number of promising drugs is now in the development by major pharmaceutical companies.

A significant improvement in treatment of this malignancy was recently achieved by the use of photodynamic therapy. Researchers from the Perelman Schools of Medicine at the University of Pennsylvania tried a new conservative lung-sparing surgery in combination with photodynamic therapy technique.  Surgery in this case intends to remove only the bulk of tumor. Any metastases (which are present almost always) remain in the lung. Photodynamic therapy is used to eliminate them, or at least to slow down their development.

The idea of photodynamic therapy is quite interesting. A special drug capable of accumulating in cancer cells is given to the patients. Drug is not toxic and does not create any major side effects. But it has a special property: when irradiated by the certain type of light, it starts to produce very aggressive free radicals that kill and damage the surrounding cells. Since drug is located mostly in cancer cells, they will be the most affected by the radicals. Initial results published in 2012 indicate that patients who underwent this treatment survive for at least two years, which is twice longer than average post-diagnosis survival period of just one year typical for this disease.

Gene therapy for lung mesothelioma is also being investigated. In the course of this therapy, specific genes capable of killing cancer cells get delivered to tumor with the help of modified herpes simplex virus. Phase 1/2 clinical trials are now on the way to establish if this therapy is effective.

Not everyone might be at risk – genetic tests need to be developed

Recently, it came to the attention of scientists that the incidences of malignant mesothelioma are higher in some families. This implies that there are specific genes responsible for predisposition to this disease. If the genes are identified and proper tests developed, we can clearly identify those people who are really at risk and direct the resources to monitor their health closely instead of trying to follow everyone with the known exposure to asbestos.

Lots of work needs to be done to deliver the meaningful help to people with asbestos-linked lung malignancies. The recent progress in treatment and management of these conditions offers the hope that real improvements are not far away.