July is Sarcoma Awareness Month. We asked Dr. Don C. Beringer with Northside Hospital Orthopedic Institute to answer some of the most common questions he receives about sarcoma.
What is sarcoma?
Sarcoma is a malignant tumor of connective tissue, primarily occurring in or around the muscles and bones of the trunk and extremities. These are rare tumors, accounting for only 1% of all malignancies. Although there are over 70 subtypes of sarcomas, there is a general lack of familiarity with these tumors due to their rarity.
What is the most common type of sarcoma?
Soft tissue sarcomas occur more frequently than bone sarcomas. Of the 12,000 new sarcoma cases in the United States each year, 90% of these are soft tissue sarcomas. Owing to their rare occurrence, they are typically referred to cancer centers with an experienced team of sarcoma specialists. They tend to invade the surrounding tissue and the prognosis for spread to distant parts of the body (metastatic disease) or mortality depends on factors such as size, microscopic appearance (grade), and the extent of disease at the time of diagnosis. Treatment can be complex, usually involving surgery, and may require radiation or chemotherapy.
Who is at risk for getting sarcoma?
Sarcomas can occur at any age and affect people throughout life. The majority of bone sarcomas are called osteosarcoma, occurring more commonly in children and adolescents. However, there is another peak in the incidence of bone sarcomas in older adulthood.
On the other hand, the majority of soft tissue sarcomas occur in adults with only 15% of these tumors affecting children. Previous radiation treatment, chronic lymphedema, unusual chemical exposures, and rare hereditary/genetic abnormalities are risk factors for developing soft tissue sarcomas. However, it is very important to stress there are no known risks or causes for the vast majority of soft tissue sarcomas.
How important is screening and early detection?
Unlike more common forms of cancer, there are no screening tests for early soft tissue sarcoma. Sarcomas can be easily overlooked or difficult to diagnose because they can mimic many common benign soft tissue tumors. Additionally, they are usually asymptomatic early on, making delay in diagnosis a common occurrence. However, early detection, before the tumor has reached a significant size or spread, is associated with a much better prognosis.
Are any new diagnostic tools or treatments on the horizon?
Evaluation requires that appropriate imaging studies be done before a carefully planned tissue biopsy. Standard imaging studies, including X-ray, MRI, CT and bone scan, have been utilized over many years for evaluation and surveillance of sarcoma. However, current versions of these tools employ very high-resolution output for precise evaluation of tumor extent and surgical planning. For example, high-resolution CT with 3-D reconstruction is commonly used for surgical planning in bone sarcoma. In addition, CT-guided biopsy is a technique for precisely localizing the lesion for tissue sampling while avoiding unnecessary trauma, bleeding, or contamination of surrounding tissue.
PET/CT is an imaging study that combines nuclear medicine with imaging to evaluate both metabolic activity and the specific location of potential tumors. It is a very sensitive test for the presence of sarcoma anywhere in the body, so it is increasingly used for initial determination of the extent of a tumor to support treatment decisions at the start of treatment or in follow-up surveillance for recurrence.
Finally, a long-standing principle of effective sarcoma management is coordinated, multidisciplinary treatment that includes specialists in orthopedic or surgical oncology, medical oncology, pathology, radiology, and radiation oncology. Once a diagnosis is established, the patient is introduced to the multidisciplinary team and presented at weekly multidisciplinary conferences. Treatment planning and monitoring of progress occurs within this team environment. Decisions for treatment are made and typically include either surgery, radiation, chemotherapy, or a combination of these. More than 180 sarcoma patients were presented and discussed at Northside Hospital Cancer Institute multidisciplinary conferences in the past year, leading to over 50 sarcoma operations during that time period.
What can we do, if anything, to prevent sarcoma?
At this point, there are no known nutritional, environmental or behavioral measures for the prevention of sarcoma in the vast majority of patients. However, in patients with risk factors such as previous radiation treatment/exposure, and known genetic predispositions, close monitoring and surveillance to identify potential sarcoma at its earliest stage is recommended.
What is the current survival outlook?
The prognosis for patients with sarcoma varies widely. More important than the specific tissue subtype of sarcoma, the “stage” of the tumor at the time of diagnosis determines prognosis. Stage is determined by tumor size, regional or distant spread, and the tumor grade, or its specific appearance under the microscope.
We view prognosis in terms of the extent to which the sarcoma can be controlled. Obviously, the goal is complete removal of the primary site of sarcoma with no spread or recurrence. We refer to this as “disease-free survival.” If a tumor persists or recurs after initial treatment, it may be either localized only to the anatomic area where it initially arose, progress into the region around the initial tumor, or spread to distant sites such as the lung or liver. Distant spread, or metastatic disease, is usually associated with significant loss in quality of life and a markedly shortened life expectancy. When disease persists, the sarcoma team works diligently to achieve “progression-free survival,” often with either systemic chemotherapy or radiation.
Seventy percent of sarcomas are localized to one site and the 5-year survival for this group is 80%. If the initial tumor has spread, the prognosis for survival falls off significantly. Regional spread is associated with about a 50% 5-year survival and patients with metastatic disease at diagnosis survive 5 years only 15% of the time.
What is the primary message you want people to know about sarcoma?
Although both bone and soft tissue sarcomas are rare diseases with widely variable behavior, long-term survival can be anticipated in 80% with a well-trained team experienced in managing sarcoma in a multidisciplinary environment. Any tumor that is either deep or appears to be at least the size of a golf ball should be referred to a sarcoma center prior to biopsy or excision. Complete excision of these tumors with a “tumor-free” margin is critical to satisfactory, disease-free outcomes.
Limb-sparing approaches are most common and require detailed imaging and treatment planning. Dramatic improvements in survival are associated with the development of effective chemotherapy and new targeted therapies in coordination with excision. Radiation continues to play a critical role in the management of these tumors.
