Dec. 21, 2018
Rhabdomyosarcoma (RMS) is a rare cancer that forms in soft tissue, and most often affects children. RMS can arise anywhere in the body including the genitourinary system, involving the bladder, prostate or vagina. At Mayo Clinic, each child's case is reviewed by pediatric oncologists, radiologists, surgeons and radiation oncologists, and a care plan is created with the family. The Mayo Clinic approach to sarcomas is multifaceted and unique, offering cutting-edge treatments and research to beat the RMS beast.
Mayo Clinic's surgical sarcoma team
Mayo Clinic specialists approach surgery for pediatric genitourinary RMS as a multidisciplinary team. These rare, complex tumors must be approached by a team of surgeons that specializes in a particular organ or organs who together can create a customized surgical plan.
Depending on which abdominal and pelvic structures are involved or near the tumor, the following subspecialists may be involved: pediatric urologists, pediatric surgeons, vascular surgeons, orthopedic oncology surgeons, hepatobiliary surgeons and peripheral neurosurgeons, and genitourinary oncology surgeons.
"Treating pediatric RMS is like building a house. You need different experts to build each part of your house ― plumbers, electricians, and so on. With RMS surgery, it takes a whole team of experts to work on these complicated tumors and all of the involved organs," says Patricio C. Gargollo, M.D., a pediatric urologist at Mayo Clinic's campus in Rochester, Minnesota. "We are blessed at Mayo Clinic to have an amazing team of people who are dedicated, talented and well-versed in sarcoma surgery to give these kids the best chance at beating this rare cancer."
3D models for surgical planning
"Another unique component of sarcoma care at Mayo Clinic is that we have the benefit of creating 3D-printed models of a child's tumor," says Candace F. Granberg, M.D., a pediatric urologist at Mayo Clinic in Rochester, Minnesota. Using data from a child's MRI or CT scan, pediatric radiologists construct 3D, color-coded models of the tumor and surrounding structures to assist the surgical team with preoperative planning; models are brought into the operating room for reference during surgery. "It is one thing to look at a scan and try to visualize how things will look during surgery. It is another to be able to hold the 3D model in your hands, turn it in every direction and see exactly where we need to cut to get the entire tumor out, or plan where we need to give intraoperative radiation," Dr. Granberg says. "Additionally, families see the models before surgery to gain a better understanding of their child's tumor."
Intraoperative radiation therapy for RMS
At times, tumors extend into vital structures, limiting resection and increasing the risk of leaving microscopic cancer behind. In these cases, the area can be treated with intraoperative radiation therapy (IORT) — a high dose of radiation applied directly to a target area where a tumor is difficult to remove. During surgery, other structures are moved out of the way to allow IORT to be delivered to specific areas, avoiding radiation of sensitive surrounding tissues.
Proton beam therapy for RMS
Some children with RMS receive proton beam therapy. Mayo Clinic's program differs from most other programs in the United States. It exclusively features intensity-modulated proton beam therapy with pencil beam scanning — spot scanning to deposit streams of protons back and forth through a tumor, closely targeting the tumor and sparing healthy tissue.
Hyperthermic intraperitoneal chemotherapy
Mayo Clinic has one of only a few pediatric hyperthermic intraperitoneal chemotherapy (HIPEC) programs in the country, offered to select patients. HIPEC is a highly concentrated, heated chemotherapy treatment delivered directly to the abdomen during surgery. Unlike systemic chemotherapy, which circulates throughout the body, HIPEC delivers chemotherapy directly to cancer cells in the abdomen, allowing for higher treatment doses. Heating the solution may improve absorption of drugs by tumors and it destroys microscopic cancer cells remaining in the abdomen after surgery.
"When cancer cells spread beyond the primary tumor, standard intravenous or oral chemotherapy drugs won't be able to kill them," Dr. Gargollo says. "By resecting every visible tumor, called cytoreductive surgery, then applying HIPEC, we can treat microscopic cancer cells that would eventually grow and be refractory to standard treatment."
Fertility preservation program
Mayo Clinic's Fertility Preservation Program offers options for children at risk of having future fertility impaired by their cancer treatments. A team of specialists determines if a child is at risk, then provides options for both pre- and post-pubertal boys and girls in a timely fashion, so as not to delay cancer treatment.
"Though much of this work is experimental, the fact that we can cryopreserve tissue for future fertility is promising, especially for families who are already going through a difficult time with dealing with their child's cancer diagnosis and treatment," says Dr. Granberg.
Precision medicine: Research for the future
At Mayo Clinic, the goal is to transform how pediatric cancer is treated by providing a timely and cost-effective assessment of the best potential therapies for each child. The approach involves using Mayo-developed genomic tools to provide a comprehensive strategy for the molecular characterization of individuals' tumors. This approach can identify treatment targets missed by commercial tests.
Mayo Clinic investigators have developed a 3D microcancer assay, growing microtumors from patient tissue. By studying drug responses to these microtumors, personalized, targeted treatment plans can be generated, avoiding a catch-all approach that gives unnecessary drugs with their inherent side effects and unacceptable failure and recurrence rates.
For more information
Mayo Clinic. Pediatric Urology.
Mayo Clinic. Intraoperative radiation therapy (IORT).
Mayo Clinic. Proton Beam Therapy Program.
Mayo Clinic. Cytoreductive surgery and HIPEC offers effective treatment for selected patients with peritoneal carcinomatosis.
Mayo Clinic. Children's Center Fertility Preservation Program.