What’s New in Lung Carcinoid Tumor Research?

Many medical centers around the world are researching the causes and treatment of lung carcinoid tumors. This disease is challenging to study because it is not common. But each year, scientists find out more about what causes the disease and how to improve treatment.

Genetics

Researchers have made great progress in understanding how certain changes in the DNA inside normal cells can cause them to become cancerous. DNA is the molecule that carries the instructions for nearly everything our cells do. We usually look like our parents because they are the source of our DNA. But DNA affects more than how we look.

Some genes (parts of our DNA) contain instructions for controlling when our cells grow and divide into new cells. Certain genes that cause cells to grow, divide, and stay alive are called oncogenes. Others that slow down cell division or cause cells to die at the right time are called tumor suppressor genes. Cancers can be caused by DNA changes that turn on oncogenes or turn off tumor suppressor genes.

Researchers have found many DNA changes in lung carcinoid cells in the past few years. The hope is that continued research in understanding these changes will lead to new tests for earlier diagnosis and new drugs for more effective treatment.

Diagnosis

Because the outlook and treatment of lung carcinoids and other types of lung cancer are very different, it’s important to be able to tell these cancers apart as soon as possible. Researchers have made great progress in developing tests that can detect specific substances found in the cells of carcinoid tumors but not other lung cancers. Most of these tests treat tissue samples with special man-made antibodies in the lab. The antibodies are designed to recognize specific substances in certain types of tumors.

Treatment

Doctors are learning how to treat lung carcinoids more effectively. For example, newer surgical techniques allow doctors to remove parts of the lung through smaller incisions, which can result in shorter hospital stays and less pain for patients. And new radiation therapy techniques help doctors focus the radiation more precisely on tumors, lowering the amount of radiation that normal tissues get and reducing side effects.

Carcinoid tumors that have spread remain hard to treat. Most carcinoid tumors grow fairly slowly. Because standard chemotherapy drugs work by attacking quickly growing cells, they are not very effective against carcinoid tumors.

Newer drugs called targeted therapies may prove to be more effective against carcinoids. Targeted therapies attack the parts of cancer cells that make them different from normal, healthy cells. Each type of targeted therapy works differently, but they alter the way a cancer cell grows, divides, repairs itself, or interacts with other cells in some way.

The targeted therapy drug sunitinib (Sutent^®) has been shown to be helpful in treating neuroendocrine tumors that start in the pancreas. More studies of this drug in carcinoid tumors (including lung carcinoid) are in progress.

Targeted drugs called angiogenesis inhibitors affect the growth of new blood vessels, which tumors need to grow larger. Some of these drugs are already used to treat other types of cancer and are now being studied for use against carcinoid tumors. Examples of these drugs include bevacizumab (Avastin^®), pazopanib (Votrient^®), axitinib (Inlyta^®), and cabozantinib (Cometriq^®).

Researchers are also trying to improve upon drugs related to somatostatin, which help some people with carcinoid tumors. An example is pasireotide (Signifor^®) , which may prove to be more potent than current drugs such as octreotide and lanreotide. Another new approach is to pair drugs similar to octreotide with a radioactive atom . These drugs are like those used for some radionuclide scans, but the radiation is stronger. The drugs bind to the carcinoid cells, delivering radiation to those cells and limiting the effects on normal cells. In early studies, this type of treatment has helped some patients with advanced carcinoid tumors that were no longer responding to other treatments, but more studies of these new drugs are needed.

These and other new drugs are now being studied in clinical trials.