New Therapies Target Biological Markers for Salivary Gland Cancer

Published in Greater Washington Area - Spring/Summer 2020

Photo: Karim Boudadi

New treatments for salivary gland cancers are now being provided at the Johns Hopkins Kimmel Cancer Center at Sibley Memorial Hospital.

Salivary gland cancer affects between 2,000 and 2,500 people in the U.S. every year, accounting for 6 to 8 percent of all head and neck cancer cases. Symptoms include irritated and swollen salivary glands, a bad taste in the mouth, difficulty opening the mouth, dry mouth, pain in the face or mouth, or swelling of the face or neck or under the tongue.

These cancers are typically treated with surgery and radiation — and in some advanced, aggressive cases, chemotherapy. Johns Hopkins, a high-volume center for the treatment of salivary gland cancer, is offering new, innovative treatments, such as hormone therapy, that target tumors based on their biological characteristics and improves survival rates.

“There’s a spectrum of cancers within salivary gland cancers that have very different biological characteristics,” says Karim Boudadi, a medical oncologist at the Johns Hopkins Kimmel Cancer Center at Sibley Memorial Hospital and professor of oncology at the Johns Hopkins University School of Medicine. “They can express certain molecular markers that we typically associate with other types of cancer.”

Patients with tumors that have high expression of the androgen receptor, which is commonly associated with prostate cancer, are candidates for hormone therapy. Patients with tumors that have high expression of the human epidermal growth factor receptor 2 (HER2) gene, which is commonly associated with breast cancer, are candidates for anti-HER2 therapy.

While less toxic than chemotherapy, side effects of androgen deprivation hormone therapy in both men and women are akin to inducing menopause, Boudadi says. These include hot flashes, muscle and joint aches, fatigue and enlargement of breast tissue in men.

The average course of hormone therapy — administered in pills or shots — is six months to one year, Boudadi says, although he generally won’t stop therapy if it appears to be working. The response duration varies but usually isn’t above two years, he says.

Hormone therapy and anti-HER2 therapy can be helpful in patients with advanced disease that has spread in their body or recurred after surgery and/or radiation and in patients whose tumors can’t be removed surgically. If the disease is spreading rapidly or a patient is very symptomatic, the treatment regimen may also include chemo.

“In cases where the cancer is very slow-growing, we use a watch-and-wait approach because chemo doesn’t always improve overall survival outcomes,” Boudadi says.

Androgen receptor expression is most commonly seen in a subset of salivary gland cancers called salivary ductal carcinoma, Boudadi says, in which 80% to 90% of tumors express the androgen receptor.

For cancers expressing the androgen receptor, hormone therapy appears to halt tumor growth and improve overall survival rates compared with patients who don’t receive hormone therapy treatment. The five-year survival rate of salivary gland cancer patients is 71%, but the rate varies, depending on the stage of the cancer when it was diagnosed and whether or not the cancer has spread to other parts of the body, he says.

For patients whose tumors express both the androgen receptor and HER2, Boudadi and his team will treat them sequentially, starting with whichever therapy they believe will be most effective.

Although salivary gland cancer represents only a small subset of head and neck cancer cases, Boudadi anticipates advancements in hormone therapy.

“There’s a newer generation of hormone therapy treatment,” he says. “I look forward to seeing trials of those newer drugs for salivary gland cancer.”

Immunotherapy Targets Tumors’ Genetic Characteristics

Oncologist Karim Boudadi treats head and neck cancers based on tumor genetics.

A photo shows Sue Hallowell.

Individualized Treatment for the Full Range of Head and Neck Cancers

The Johns Hopkins Kimmel Cancer Center in the greater Washington area provides a full range of treatment and post-treatment services.

The proton machine provides targeted treatment for head and neck tumors.