Preserving Life and Limb

Limb-sparing procedures and technological advances are making modern treatment of soft-tissue sarcomas less drastic.

by Alicia Di Rado

Brachytherapy—the administration of radiation therapy locally through radioactive seeds—holds promise as part of a limb-sparing treatment program for patients with soft-tissue sarcomas.

A team of Keck School of Medicine and USC/Norris Comprehensive Cancer Center radiation oncologists, orthopaedists and preventive medicine researchers incorporated brachytherapy in the treatment of patients diagnosed with soft-

tissue sarcomas. Five years after treatment, 83 percent of patients in the trial had survived; results echo those of a similar trial done at Memorial Sloan-Kettering Cancer Center, prompting physicians to hold out hope that the radiotherapy technique will augment oncology’s anti-sarcoma arsenal.

Soft-tissue sarcomas are relatively rare, with fewer than 10,000 diagnoses expected in the United States in 2005. The term sarcoma comes from the Greek word meaning “fleshy growth.” Soft-tissue sarcomas grow in the connective tissues of the body, such as muscles and nerves.

When cancer is caught early enough, about 90 percent of patients survive five years; but in those whose cancer has spread, the chance of survival drops significantly. Treatment for sarcoma itself can change a patient’s life, too.

Although sarcomas can arise practically anywhere in the body, about half are found in the arms or legs. In the past—and still sometimes today—surgeons have had to amputate a limb to treat soft-tissue sarcomas.

But limb-sparing procedures and new technological breakthroughs are helping make modern treatment less drastic, according to Oscar E. Streeter Jr., M.D., associate professor of radiation oncology at the Keck School and USC/Norris. Experts estimate that only 5 to 15 percent of contemporary soft-tissue sarcoma surgeries in the United States require amputation.

Radiotherapy has been a mainstay of limb-sparing sarcoma treatment. Radiation damages tumor cells’ DNA so they can no longer reproduce themselves.

Used either before surgery, to shrink a tumor, or after surgery, to kill remaining cancer cells, radiotherapy has helped physicians preserve patients’ limbs.

Because sarcoma cells can spread and evade surgery more than many other cancerous cells, radiation oncologists must be more aggressive and cover more territory when they irradiate tissue. They must subject larger swaths of the body around the tumor site to radiation, to try to hit cancerous cells that may have moved beyond the original tumor.

With brachytherapy, Streeter explains, radiation oncologists intend to focus radiation where it is most desired. By applying radiation exactly where they want it, they will prevent the radiation from unnecessarily harming skin that is healing from cancer surgery, while sending X-rays to the specific areas where lingering cancer cells are most likely to remain.

In this technique, after a surgeon removes the tumor from the patient, the radiation oncologist then inserts several catheters through the skin and into the cavity left by the tumor. After the patient recovers from surgery, a radiation oncologist threads tiny radiation sources through the catheters and into the cavity.

This radiation treatment can often be done over just a few days, and then the catheters are removed.

In the USC study, researchers looked at 12 patients with soft-tissue sarcomas in the arms or legs (or both) removed between 1994 and 1995 by Lawrence Menendez, M.D., USC director of orthopaedic oncology. Eight of the patients had chemotherapy before the surgery, while 10 received traditional external beam radiation therapy before the surgery and one received the external beam radiation therapy after the surgery. All 12 patients received high-dose-rate brachytherapy after surgery.

The researchers followed up to see how patients were doing five years later. In one patient, cancer had returned locally at the tumor site about three years after treatment. In another, cancer had returned both locally and away from the tumor site after about two years. Another two patients developed distant metastases early (at five and 12 months, respectively), and both patients died. Other patients remained disease-free.

Overall, sarcomas recurred in a third of the patients.

The Keck School physicians’ experiences indicate that high-dose-rate brachytherapy, combined with other therapies, can reduce the risk that sarcoma will recur at the original tumor site, Streeter says. In addition, the researchers believe that chemotherapy before surgery may be important to preventing cancer’s return locally, as well as helping improve overall and disease-free survival.

Sant Chawla, M.D., a USC medical oncologist specializing in sarcomas, says that while physicians do not know exactly why patients develop sarcomas, they do recognize some sarcoma risk factors. Patients who received ionizing radiation for another cancer, such as breast cancer, or who have damaged lymph nodes may be at higher risk. Those with other inherited conditions, such as neurofibromatosis, Gardner’s syndrome, Li-Fraumeni syndrome and retinoblastoma, also appear to face a greater risk of sarcomas. Certain chemicals such as dioxin and ingredients in some herbicides also might raise risk.

Because the disease is rare and can arise in so many different locations, it is often not detected until the tumor has grown significantly. Experts recommend that anyone experiencing growth of an unusual lump have it checked by a physician. Most growths are benign, but only a sample of the tissue can indicate for certain.

For more information about brachytherapy, call 1-800-USC-CARE (1-800-872-2273). For more information about sarcomas and their treatment, go to www.cancer.org or www.sarcomaalliance.com.