Sarcomas – Cancers That Affect Connective Tissues
Because most people are not familiar with cancer, it can be easier for us to describe what a sarcoma is not. When most people think of cancer, they are actually thinking of carcinomas. Carcinomas are cancers of glands or the lining of an organ. For women, this commonly includes breast, ovarian, and lung cancer. More specifically, these are referred to as adenocarcinomas of the breast, ovary, and non-small-cell or small-cell carcinoma of the lungs. For men, common adenocarcinomas include those of the prostate, lung, and colon. Collectively, carcinomas represent the vast majority of all cancers. There are other cancers that sarcomas are not: leukemias and lymphomas are cancers of blood cells. Melanomas and brain tumors (gliomas) also arise from unique cells.
In contrast, sarcomas are cancers of the bony skeleton (the skull, vertebrae, ribs, and extremities), and also the muscle and other tissues attached to, supporting, or joining those bones. Connective tissues include fat, blood vessels, fibrous and nerve tissue, skeletal and smooth muscle, etc. - all those that connect the skeletal tissue.
Skeletal Muscles and Smooth Muscles
When you flex your arm, bringing your wrist to your shoulder, your brain first sends a command signal via your nerves to the muscles in your arm to carry out this action. This flexes the arm as the muscles contract with the support of your tendons and ligaments. These types of muscles are referred to as skeletal muscles and are under our voluntary control.
Smooth muscles are responsible for automatic functions such as contraction along the intestinal tract as digesting food moves through your gastro-intestinal system, blood vessels (during blood vessel tightening and relaxing to force blood to different areas of the body based on demand), and the uterus (during menstrual periods or birthing). These functions are not under our voluntary control and are dependent on what are called “smooth” muscles.
Who is at risk?
Carcinomas occur more commonly among older individuals. Some carcinomas can be attributed to lifestyle choices. Smoking cigarettes, eating an unhealthy diet, and lack of exercise can all contribute to development of a carcinoma. In contrast, sarcomas occur in people of all ages – from newborns and infants to teenagers, young adults, and seniors. Also unlike carcinomas, a sarcoma isn’t thought to be associated with any lifestyle choices. You can’t get sarcoma from eating the wrong foods, making love, or insufficient exercise.
Why is Sarcoma difficult to diagnose?
Though there are many types of sarcomas, very few doctors have experience in dealing with them. This is not because they are mentally slow or poorly trained or inadequately experienced. Simply, sarcomas are rare diseases. For example, many doctors who practice in general pediatrics for decades may not encounter even one case of osteosarcoma (the most common sarcoma of bone). This is why it can be difficult to establish a sarcoma diagnosis or pursue the appropriate treatment for sarcoma patients.
At major sarcoma centers across the US, such as those participating in SARC trials, physicians might see one or two new osteosarcoma patients a week. The medical personnel at these high-volume centers have the valuable experience that is considered essential in the management of sarcoma. Experience does matter.
The American Cancer Society (ACS) estimates that there are about 15,000 cases of sarcoma in the US each year. Sarcomas are relatively more common among children, accounting for 15% of pediatric cancers, but become less frequent with increasing age, accounting for approximately only 1% of all adult cancers. It is the most common solid tumor found in young adults today.