Soft-tissue sarcomas are a family of cancers that arise from supportive (connective) tissue other than the bones. Specifically, soft-tissue sarcomas may afflict the muscles (rhabdomyosarcoma and leiomyosarcoma), fibrous tissue (fibrosarcoma and malignant fibrous histiocytoma), fat cells (liposarcoma); the blood vessels (angiosarcoma), and the joints (synovial cell sarcoma). Children are the most common victims of these soft-tissue sarcomas; adults are rarely affected.
Soft-tissue sarcoma usually starts as a painless mass or lump, although in some cases pain occurs before the lump, but only for a short time since these cancers grow rapidly. Any unexplained lump should be investigated promptly, particularly if it is in the thigh since many soft-tissue sarcomas originate in that region. Similarly, a lump in the groin may indicate a sarcoma of the bladder, vagina, or uterus, although other disorders such as a hernia or lymphoma are more frequent causes. Recurrent earache or facial paralysis may be an early symptom of rhabdomyosarcoma of the middle ear. This type of sarcoma also may originate in the supporting structure of the eye.
In addition to a thorough physical examination, specific diagnostic studies used when soft-tissue sarcoma is suspected include (depending upon the affected part), X rays, CT scans, ultrasonic (echo) examinations, kidney studies and others. A biopsy is an essential diagnostic step, and precautions such as those followed for bone biopsies should be taken. Tissue for biopsy may be obtained either through a surgical incision or with a hollow needle. In any instance, care should be taken to minimize the damage and to make sure that the wound is closed without drains to reduce as much as possible the risk of spread and infection.
Before developing a treatment plan, staging to determine the extent of disease and specific type of cancer is usually recommended. Microscopic examination of the sarcoma cells also is recommended by many authorities to determine the cell grade. Grade One sarcomas have cells that are fairly well differentiated and have few reproducing or dividing cells. In contrast, Grade Three sarcomas are relatively undifferentiated and have many reproducing cells. Grade Two sarcoma lies between these two.
In general, the lower the grade, the better the prognosis.
The treatment of soft-tissue sarcoma has traditionally involved extensive surgery aimed at removing the cancer and surrounding tissue. Often this meant limb amputation and removal of muscles. More recently, however, a combination of treatments—less radical surgery, radiation therapy, and chemotherapy—has been used with good results. The timing and administration of the treatments depends upon staging, grade and other circumstances. In most cases limbs and muscles can be saved without lowering the rate of cure. Surgical treatment, however, may entail removal of the lymph nodes from the area of the tumor to help prevent the cancer’s spread to other parts of the body. Postsurgery radiation therapy may be given to the tumor site and regional lymph nodes.
The prognosis for soft-tissue sarcoma appears to be improving with the increased use of combination treatment. This is especially true for children. The success rate is clearly related to the stage of the disease and possibly to the grade of tumor cell. For example, Stage I and II rhabdomyosarcoma in children has a 60 to 80 percent cure rate, compared to cure rates of 40 and 15 percent respectively for Stages III and IV.
The prognosis is also related to the site of origin. Rhabdomyosarcoma of the eye and of the genitourinary tract are generally associated with a good prognosis (approximately 60 to 80 percent survival) compared with a 20 percent survival among patients with rhabdomyosarcoma affecting the arms and legs. As for cell grades, Grade One sarcoma is associated with a survival in the 80 percent range; Grade Two, a 40 percent survival; and Grade Three, a 20 percent survival. It should be emphasized that these are only survival rates for large numbers of patients. One cannot predict the outcome in any individual patient.
Complications of Treatment
As noted throughout this book, all cancer therapy involves certain short-term adverse reactions and possible long-term consequences. Nausea, vomiting, loss of hair, depressed production of white blood cells and resulting increased susceptibility to infection are among the short-term complications of cancer therapy. Although these can be very troubling and uncomfortable at the time, they are self-limiting and end when the therapy is completed. Some anticancer drugs may produce sterility, either temporary or permanent. Others affect the heart and other vital organs.
Although these are serious problems, the potential benefits generally outweigh the adverse effects.
Radiation therapy also produces adverse effects, including an increased potential for developing cancer in the area exposed to the radiation. Thus radiation therapy is limited to the minimum effective dosage and is carefully administered to protect surrounding tissue as much as possible. The effects of surgery, particularly amputation, are immediate and generally permanent. The development of effective combinations of treatments that minimize the radical surgery have spared the limbs and muscle tissue of many victims of bone and soft-tissue sarcomas. Improved prosthetic devices and increased attention to rehabilitation, particularly of young patients, have added greatly to the quality of life following surgery.