What’s New in Salivary Gland Cancer Research?

A lot of research on the causes and treatment of salivary gland cancer is being done in medical centers world-wide . This is a challenging disease to study because it’s quite rare and there are many types of salivary gland cancer. But each year, scientists find out more about the disease and how to better treat it.

Gene changes in salivary gland cancers

Studies have found certain gene changes in various types of salivary gland cancers. Researchers are learning more about how these changes can cause salivary gland cells to become cancer. They are also finding out that some of these gene changes can be targeted by specific drugs for treatment.

For example, in adenoid cystic cancers, a mutation in the NOTCH1 gene appears to make this cancer more aggressive and have a higher chance of cancer spread. But this also means that salivary gland cancers with this NOTCH1 mutation might respond to a category of drugs called NOTCH1 inhibitors. Some secretory cancers have an ETV6-NTRK3 fusion gene that makes TRK inhibitors a possible treatment option. More research is being done to test targeted drugs against gene changes in different types of salivary gland cancers.

As scientists learn more about these gene changes in salivary gland cancer cells, they hope to develop new targeted treatments that work better and cause fewer side effects. Someday these cell changes may also be used to diagnose salivary cancers, predict outcomes, and make treatment choices.

Treatment of salivary gland cancers

Surgery

With advances in surgical techniques, teams of head and neck surgeons and neurosurgeons can now remove small tumors and tumors near key structures, such as cancers that have spread near the base of the skull. These operations are becoming more common and successful.

Reconstructive surgery is becoming more sophisticated and successful, too. This lets surgeons do more extensive surgery to remove the cancer and improves patients’ quality of life after treatment.

Radiation therapy

New ways of giving radiation therapy now allow more precise targeting of radiation. Intraoperative radiation, where radiation is given right to the tumor site during surgery, is being studied as a better way to treat salivary gland tumors that are likely to come back. This may help when treating tumors that are close to nerves or big blood vessels and only limited surgery can be done.

Chemotherapy

Since salivary gland cancer is rare and there are so many types, knowledge about treating these cancers that have spread (stage 4) with chemotherapy (chemo) is still changing.

In general, chemotherapy does not work very well to treat salivary gland cancers. Most of the information using chemotherapy in stage 4 salivary gland cancer comes from treatment of other types of head and neck cancers.

Another area of interest is the use of chemo along with radiation after surgery in people at high risk of the cancer coming back (for example, those with cancer in the lymph nodes or a large tumor invading nearby structures).

Chemo drugs, often given along with radiation, continue to be studied in clinical trials.

Targeted therapy

As researchers have learned more about the gene changes in cells that cause cancer, they have been able to develop drugs that specifically target these changes. These targeted drugs work differently from standard chemotherapy drugs. They sometimes work when chemo drugs don’t, and they often have different (and sometimes less severe) side effects.

Studies have identified gene changes in some salivary gland cancer cells that help the cancer grow and spread. Some of these changes affect proteins that can be blocked by targeted drugs that are already used to treat other types of cancer. So far these drugs are used in cases of advanced salivary gland cancer and the tumor must be tested for specific proteins or genes before the drug can be tried. See Targeted Drug Therapy

Hormone therapy

Early research has found that some salivary gland tumors have too many receptors (proteins) for male hormones called androgens. Drugs that block these receptors or lower hormone levels, such as bicalutamide or leuprolide, appear to be helpful in treating these tumors.

Treating side effects of salivary gland cancer treatment

Even with better radiation and surgical techniques, some people still have long-term side effects, like dry mouth, from treatment for their salivary gland cancer. Photobiomodulation therapy (PBMT)  has been investigated to help with this common side effect of salivary gland cancer treatment. It is a low-level laser therapy that is applied to the salivary glands and initial studies have shown some success in people with dry mouth. More studies are needed to show that this therapy is helpful for this side effect.

Other studies are looking at different types of prevention and treatment of dry mouth including new medicines, acupuncture, hyperbaric oxygen, submandibular gland transfer, and increasing saliva production through stimulation of the taste buds and by chewing.