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Monkees' Peter Tork Dies of Rare Salivary Gland Cancer

— But what is adenoid cystic carcinoma?

MedpageToday

Fans of the 1960s TV sitcom The Monkees are mourning the death of band member Peter Tork. Tork, born Peter Halsten Thorkelson, died last month at the age of 77 from adenoid cystic carcinoma.

Tork played bass guitar and keyboards for The Monkees and was often portrayed as the "goofy" one. The show lasted two seasons, winning the Emmy Award for outstanding comedy series in 1967. Despite being a "made for TV" band, The Monkees went on to have several hit records and recorded for three years before disbanding. Tork went on to have a solo career, forming a blues band called Shoe Suede Blues.

In March 2009, Tork that he had been diagnosed with adenoid cystic carcinoma after having some difficulty swallowing and a change in his voice. A preliminary biopsy discovered that the cancer was confined to a single site. Tork explained: "It's a bad news/good news situation. It's so rare a combination (on the tongue) that there isn't a lot of experience among the medical community about this particular combination. On the other hand, the type of cancer it is, never mind the location, is somewhat well known, and the prognosis, I'm told, is good."

Tork underwent successful surgery to remove the lesion. However, in July 2009, the cancer recurred and Tork received a course of radiation therapy. In an , Tork said: "I recovered very quickly after my surgery, and I've been hoping that my better-than-average constitution will keep the worst effects of radiation at bay."

In 2011, Tork went back on the road with bandmates Micky Dolenz, Michael Nesmith, and David Jones. Jones died of a heart attack in February 2012, and the three remaining Monkees did a 45th-anniversary tour that year.

Tork's cancer returned in 2018, and he passed away on February 21, 2019. His :

"Peter's energy, intelligence, silliness, and curiosity were traits that for decades brought laughter and enjoyment to millions, including those of us closest to him. Those traits also equipped him well to take on cancer, a condition he met with unwavering humor and courage."

What is adenoid cystic carcinoma?

Adenoid cystic carcinoma (ACC) is a rare form of adenocarcinoma, a type of cancer that begins in glandular tissues. It most commonly arises in the major and minor salivary glands of the head and neck. It can also occur in the trachea, lacrimal gland, breast, skin, and vulva.

ACC tends to be a slow growing, but aggressive neoplasm, with a remarkable capacity for recurrence. Morphologically, three growth patterns have been described: cribriform or classic pattern; tubular; and solid or basaloid pattern. The cribriform pattern shows epithelial cell nests that form cylindrical patterns. The lumina of these spaces contain mucopolysaccharide secretions. The tubular pattern reveals tubular structures that are lined by stratified cuboidal epithelium. The solid pattern shows solid groups of cuboidal cells. The cribriform pattern is the most common, and the solid pattern is the least common. Solid adenoid cystic carcinoma is a high-grade lesion with reported recurrence rates of as much as 100% compared with 50% to 80% for the tubular and cribriform variants.

Each year, about 1,200 people are diagnosed with ACC in the U.S. and about 60% are women. ACC is most often found in younger and middle-age adults, but anyone of any age can be diagnosed, including children. The peak incidence for this tumor is reported to be in the fourth through sixth decades of life. Regardless of histologic grade, adenoid cystic carcinomas, with their unusually slow biologic growth, tend to have a protracted course and ultimately a poor outcome, with a 10-year survival reported to be less than 50% for all grades. These carcinomas typically show frequent recurrences and late distant metastases.

Symptoms depend on the tumor's location. Salivary gland tumors may cause painless masses in the mouth or face. Tumors of the lacrimal gland may cause a bulging eye or changes in vision. Those affecting the trachea or larynx may cause respiratory symptoms or changes in speech, respectively. Pain and facial paralysis develop frequently during the course of the disease, as ACC often spreads along the nerves. It may also spread through the bloodstream. The most common place of metastases is the lung, followed by liver and bone. It spreads to the lymph nodes in only about 5% to 10% of cases.

The cause of ACC is currently unknown, but implicate somatic mutations in the MYB oncogene and dysregulation of well-known intracellular signaling pathways; these results point to potential new drug targets.

ACC typically does not run in families. No strong environmental risk factors specific to ACC have been identified. According to the , unlike some other cancers of the head and neck, ACC is not linked to tobacco or alcohol use or infection by the human papillomavirus (HPV).

Treatment depends on many factors and may include primarily surgery and/or radiation. Both external beam and brachytherapy (internal radiation therapy) have been used successfully in patients with ACC. Chemotherapy is typically reserved to patients unresponsive to the above treatments or in those with tumors located near vital organs that are not treatable with surgery or radiation.

Clinical trials for patients with ACC can be found .

Michele R. Berman, MD, and Mark S. Boguski, MD, PhD, are a wife and husband team of physicians who have trained and taught at some of the top medical schools in the country including Harvard, Johns Hopkins, and Washington University in St. Louis. Their mission is both a journalistic and educational one: to report on common diseases affecting uncommon people and summarize the evidence-based medicine behind the headlines.