When Brittany Sullivan was 3, she was diagnosed with a rare cancer called Alveolar Soft Part Sarcoma, or ASPS. Now 30, the Nashville resident has endured years of treatment and seen her cancer return five times.
In May 2015, Sullivan joined a clinical trial at Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine. The trial, led by medical oncologist Dr. Breelyn Wilky, tested the effectiveness of immunotherapy, drugs that boost the immune system to fight cancer.
For the first 13 weeks, Sullivan flew from Nashville to Miami once a week to get immunotherapy infusions through an IV. She also took an oral drug. After the initial trial period, she flew down every three weeks for infusions.
“When it’s your only option, you find a way,” said Sullivan, a former teacher.
Sullivan got scanned every three months. Nine months after the trial started, the majority of her tumors had melted away, she said. The trial ended in February.
“It was a huge response … and at this point, the only thing left is scar tissue. There is no living disease,” Sullivan said.
Wilky said Sullivan was very receptive to the treatment.
“She's just been one of the people that had an incredible response to these immune drugs,” she said. “Most of her disease is undetectable now. She’s had an 80 percent shrinkage in tumors.”
A rare cancer
Sarcomas grow in connective tissue — cells that connect or support other kinds of tissue in your body. The tumors are most common in soft tissues such as muscles, tendons, cartilage, nerves, fat and blood vessels, or in bones.
It is a rare cancer. About 13,000 new soft tissue sarcomas and 3,000 bone sarcomas will be diagnosed in the United States in 2018, according to the American Cancer Society. About half of the bone cancers are typically in children and teens.
Osteosarcomas are the most common of the bone cancers, but other forms include Ewing sarcoma and chondrosarcoma, the second most common.
“Sarcomas are extremely rare. Sarcomas make up only about 1 percent of all adult cancers … and within the group of sarcomas, which are cancers of bone and soft tissue, there's over 100 different types,” Wilky said.
Difficult to diagnose
Because the cancer is rare, it’s sometimes difficult to diagnose, said Dr. Christopher Gannon, a surgical oncologist with Memorial Cancer Institute at Memorial Regional Hospital in Hollywood. He treats soft tissue sarcomas.
“Most sarcomas, unless they get to be very large, tend not to cause symptoms because they don’t invade other structures. They tend to wrap themselves around things instead of growing into things,” Gannon said. “More common cancers like colon cancer or breast cancer grow into and through things and can cause symptoms like pain.”
A small growth on a leg that doesn’t hurt but is growing should be checked out, he said. In most cases, it’s probably benign. “But if a few months later, it has doubled in size, that’s not normal,” Gannon said. “Keep following up.”
With bone sarcomas, diagnosing “is generally very straightforward, if you know what you're looking for,” said Dr. Theresa Pazionis, an orthopedic oncologist with the Miami Cancer Institute, part of Baptist Health South Florida. She treats sarcomas of the extremities, including bone and muscle.
“If it's the typical presentation in a child, it's fairly easy to diagnose,” she said. For example, if a teenager has slight pain during sports and has imaging, sarcoma tumors would be easy to spot because they have a signature look.
In an adult, bone sarcomas can sometimes be misdiagnosed, Pazionis said. If a 60-year-old man has leg pain and imaging shows that he's missing bone in his femur, the assumption might be cancer that’s spread from a different area, such as the lung, breast or prostate.
“Most of the time, that's not incorrect, but if your patient doesn't have a history of cancer, it's not something you can assume,” Pazionis said. The catastrophic consequences of incorrectly treating a patient who has a primary bone tumor like a sarcoma could lead to loss of a limb.
“It's easy to diagnose in children, less so in adults,” she said. “That's where a referral to an orthopedist oncologist with experience in sarcomas is going to be key.”
Treating the sarcoma
Surgery is the first treatment strategy, “but it needs to be done by an expert sarcoma surgeon because these tumors often are very deep and bigger than they appear on scans,” said Wilky, of Sylvester.
Sometimes chemotherapy is used to shrink the sarcoma before surgery and help prevent it from spreading.
Memorial only treats soft tissue sarcomas, and the most common soft tissue sarcoma seen there are gastrointestinal stromal tumors, known as GISTs, Gannon said. Memorial performs 50 to 60 surgeries per year, and treats 100-150 patients a year who need follow-up treatment for GISTs.
Bone sarcomas are so rare that Pazionis, of Miami Cancer Institute, typically sees only about 20 patients a year. Treatment usually begins with chemotherapy to shrink the tumors, surgery, then more chemo.
For certain types of inoperable tumors, a type of radiation called proton beam therapy is used. This therapy uses protons instead of X-rays to kill cancer cells, and causes little damage to surrounding cells. But not all bone sarcomas are receptive to the therapy, Pazionis said.
In general, the success rate depends on the sarcoma. With the most common type of sarcoma, the GIST, surgery is very successful.
“If you're able to surgically remove the tumor, cure rates are in the 90th percentile … if the tumor hasn't metastasized,” Gannon said. A targeted therapy for that type of tumor’s specific mutation uses chemotherapy that only affects the cells with the defect.
“Patients can be on this chemo for quite some time and have a lot of benefit with minimal side effects,” Gannon said.
Other common types of sarcoma are liposarcomas, which affect fatty tissue and are usually found in the legs. In their early stages, some liposarcomas can be successfully treated with surgery, although other types can be more aggressive, such as round-cell and pleomorphic liposarcoma.
Leiomyosarcomas, which affect smooth involuntary muscles and are usually found in the abdomen, tend to be more aggressive and have a higher rate of recurrence. “We see those most commonly in the uterus,” Gannon said. “Again, surgery is the first-line therapy.”
There are clinical trials that focus on standard treatment, trials that try to make surgery or chemotherapy better up front, and trials for patients where the disease has spread or where traditional chemotherapy is not effective, Wilky said.
Some trials involve precision medicine, which identify genetic mutations that lead to targeted therapies to attack cancer cells.
Wilky said she has a personal interest in the newest type of cancer therapy, immune therapy or immunotherapy, which was used with patient Brittany Sullivan. In some immune therapy trials, a patient’s tumor is used to generate a vaccine to fight the cancer. In other trials, immune checkpoint inhibitors take the brakes off the immune system to unleash attacks on tumors.
Sullivan said she feels so blessed that the immunotherapy clinical trial has worked so well for her.
“I’m beyond thrilled, just over the moon,” she said. “It was everything we hoped for and more.”
An earlier version of this story had incorrect references related to bone sarcomas.
Clinical Trial Information
Sylvester has more than 20 clinical trials for sarcomas underway, Wilky said. Memorial Cancer Center and Miami Cancer Center also participate in clinical trials. Patients can find trials at facilities around the world at www.clinicaltrials.gov.