What`s new in nasopharyngeal cancer research and treatment?

Research into the causes, prevention, and treatment of nasopharyngeal cancer (NPC) is being done in many university hospitals, medical centers, and other institutions around the world.

Causes, prevention, and early detection

Many studies are looking at how Epstein-Barr virus (EBV) infection and other risk factors cause cells of the nasopharynx to become cancerous. Researchers hope these studies may eventually lead to vaccines to help prevent some cases of NPC by avoiding EBV infection.

Recent discoveries about EBV, its interaction with nasopharyngeal cells, and the immune system’s reaction to EBV have led to new blood tests that may help detect NPC early and better predict the response to treatment. These tests are now being studied in areas of the world where this cancer is common.

Treatment

New surgical techniques

Advances in the field of skull base surgery such as the use of endoscopes in the nose now allow doctors to remove some tumors from hard to reach areas like the nasopharynx. This type of surgery requires a specialized team that has expertise in this field. It may offer hope for some patients with recurrent NPC and patients with the keratinizing type of NPC, which often doesn’t respond to radiation therapy.

New radiation therapy techniques

Recent advances in radiation therapy have helped improve the outlook for patients with NPC. Doctors can now use 3-dimensional images (created from CT or MRI scans) and computers to figure out how best to aim radiation at the cancer while limiting the radiation to normal tissues. This may lessen side effects. Intensity-modulated radiation therapy (IMRT) and stereotactic radiosurgery are examples of this highly-focused approach to treatment.

Another type of radiation uses protons instead of x-rays to kill cancer cells. Unlike x-rays, which release energy both before and after they hit their target, protons cause little damage to tissues they pass through and then release their energy after traveling a certain distance. This means that proton beam radiation may be able to deliver more radiation to the tumor and do less damage to nearby normal tissues. This approach is promising, but the machines needed to make protons are expensive, and there are only a handful of them in use in the United States at this time.

Doctors are also studying the best schedule for giving radiation therapy. External beam radiation treatments are usually given once a day, 5 days a week, for many weeks in a row. Studies are now under way to see if schedules that either give the doses over fewer days or give smaller doses twice a day might be more effective.

Chemotherapy

Researchers continue to develop new chemotherapy drugs, new drug combinations, and new ways to give drugs that might be more effective against advanced NPC. Several drugs that are already used to treat other cancers, such as capecitabine, oxaliplatin, and gemcitabine, have been studied for use against NPC as well.

Clinical trials are also testing ways to best combine chemotherapy with radiation therapy. For example, studies are comparing the effectiveness of chemotherapy given before, during, or after radiation therapy.

Targeted therapy

Drugs that target specific parts of cancer cells may prove to be useful against NPC and have fewer side effects than standard chemotherapy drugs.

The drug cetuximab (Erbitux), which targets the EGFR protein, is already being used in some cases of NPC that recur or keep growing after treatment with chemotherapy. Other drugs that target EGFR are also being studied for use against NPC, including nimotuzumab and icotinib.

Other newer drugs target a tumor’s ability to develop new blood vessels, which they need in order to grow larger. These drugs are called angiogenesis inhibitors. Several of these drugs are now being tested for use against NPC, including bevacizumab (Avastin^®), sorafenib (Nexavar^®), and pazopanib (Votrient^®).

Immunotherapy

NPC seems to be caused at least in part by infection with the Epstein-Barr virus (EBV). Although patients’ immune systems can be shown to have reacted against EBV, this doesn’t seem to be enough to kill the cancer. Researchers are trying to use different ways to boost the immune system or help it better target EBV-infected cells.

One way to do this is to remove T lymphocytes (immune system cells) from the blood of patients with NPC and alter them in the lab to increase their numbers and their power to kill EBV. The cells are then injected back into the patients. Early results with small numbers of patients have been promising, and larger studies of this technique are now under way.

Gene therapy

Scientists have recently discovered how certain gene mutations (changes) in nasopharyngeal cells may cause them to become cancerous. A clinical trial using a virus to replace the damaged tumor suppressor gene p53 in the cancer cells had some promising results. This approach is still being studied.