Laurence Baker, DO

Professor of Internal Medicine, Division of Hematology/Oncology

Professor of Pharmacology And Head of Clinical Research

University of Michigan Comprehensive Cancer Center

Chair, Southwest Oncology Group (SWOG)

Founding Member, First President and Chairman of the Board, SARC

 

When most people think of cancer, what comes to mind is carcinoma.  This is a cancer of glandular tissue or the lining of organs.  For women, this commonly includes types such as breast, ovarian, and lung cancer.  More specifically, these are referred to 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 and colon.  Collectively, these represent about 95% of all cancers.

Sarcoma is a cancer of the bony skeleton (ie. the skull, vertebrae, ribs, and extremities), and also the tissue attached to, supporting, or joining those bones.  These connective tissues include fat, blood vessels, fibrous and nerve tissue, skeletal and smooth muscle, etc. - all those that connect the skeletal tissue.  If I were to flex my arm, bringing my wrist to my shoulder, my brain would first send a command signal via my nerves to the muscles in my arm to carry out this action.  This would cause flexion of my arm from the muscles contracting with the support of my 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 track (used to push food being digested through your body), blood vessels (during vasodilation/vasoconstriction to divert blood to different areas of the body based on transient demand), and the uterus (used during menstrual periods or giving birth).   These types of functions are not under our voluntary control and therefore are smooth muscle dependent.

Carcinomas occur more commonly among older individuals and can be attributed to various lifestyle choices.  Smoking cigarettes, having a faulty diet, and lack of exercise can all contribute to the development of a carcinoma.  In contrast, sarcomas can occur in people of all ages – from newborns, infants, teenagers, to young and mature adults.  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 from insufficient exercise.

Despite there being many types of sarcomas, very few physicians have experience in dealing with them.  This is neither a reflection of intelligence nor is it dependent on how long they’ve been practicing; where they received their medical degree; or did their residency.  This fact is simply a reflection of the rarity of the disease.  I knew a man that practiced in general pediatrics for 70 years and not once over the course of his career did he encounter a case of osteosarcoma (the most common sarcoma of bone).  This is the reason why it is not uncommon for there to be difficulties in reaching a diagnosis or sometimes why the wrong direction may be pursued in the management of sarcoma patients.

At major sarcoma centers across the US, such as those participating in SARC trials, physicians might see 1 or 2 osteosarcoma patients a week.  The medical personnel at these high-volume centers have the valuable experience that is considered essential in the management of sarcomas.  Experience does matter.

Sarcoma is a cancer of connective tissue, or the manifestation of malignant (cancerous) tumors through irregular cellular division in the bones or the soft tissue that may metastasize (or spread) to other parts of the body.  They can occur anywhere in the body and the location of the tumor is an important variable that greatly influences treatment and outcome. 

 

Types of Sarcoma:

Soft tissue Sarcoma:  Soft tissue sarcomas are the most frequently occurring sarcomas and are a group composed of more than 50 different subtypes.  All these subtypes differ in terms of their tissue of origin, clinical behavior, age of occurrence, aggressiveness, the way they spread, genetic alterations, and their sensitivity to certain therapies.  This group of sarcomas comprises only 1.6% of all malignant tumors diagnosed country-wide, representing between 6,000 and 8,000 new cases per year.  Click here to view a glossary of terms for Soft tissue sarcoma subtypes.

 

Sarcoma of the bone: Tumors under this category are very rare and account for only 0.2% of all cancers in the country, and it was approximated by ACS that 4,700 new cases in the United States were diagnosed in 2007. Click here to view glossary of terms for Bone Sarcoma subtypes.

 

Overall Incidence: The American Cancer Society predicts over 10,000 cases of sarcoma will be diagnosed in 2008.  Sarcomas are 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.