What is a Sarcoma?
A disease of mesenchymal origin
Obligatory—This is not medical advice
The names of most cancers are rooted in their tissue or origin. Conveniently, their locations are used as adjectives. Lung cancer is from the lung. Breast cancer is from the breast, and so on and so forth. Sarcoma is not so simple. Rather, sarcoma is a family of neoplasms that can originate nearly anywhere in the body. As I tell the disoriented fellows who wander into my clinic, from an oncologist’s standpoint, sarcoma is a state of mind. This is partly why the field is so multidisciplinary, by its nature. This is not to say that other oncologists don’t work closely together with multiple types of surgeons, radiation oncologists, etc. It’s just to say that we’re like the rest of medical oncology, only more so.
See the following figure, from a 2018 Cancer Letters Paper, which demonstrates the heterogeneity of these diseases.1
The word ‘sarcoma’
I suppose that if we’re looking to ground ourselves, it’s best to start with the name. Sarcoma was derived from the Greek term ‘sarkoun,’ which loosely translates into ‘fleshy substance’ in conjunction with ‘oma’ which indicates a mass. Therefore, sarcoma is a mass of fleshy substance. The number of distinct sarcoma diagnoses continues to expand, but it is often quoted that there are in excess of 50 subtypes. These are best divided into bone and soft tissue sarcomas.
Epidemiology
Sarcomas, in aggregate, represent about 1% of cancers in adults. Recent papers, including the annual Cancer Statistics, anticipate ~4000 bone cancers, and 13400 soft tissue cancers in 2023. This number has been relatively stable over the last few years. There will also are estimated to be 7000 deaths from these conditions in 2023.2
As you can see, the distribution of bone cancers is bimodal, indicating that there are two primary populations to get bone cancers—children/adolescents, and the elderly. For soft tissue sarcomas, while there are certainly some in the young, it predominantly is a disease of the elderly.
Now, understand, that this is us taking a HUGE step back and looking at the population as a whole. Demographics may be different for each specific subtype. Remember, we said there are over 50 different types.
What are symptoms prior to diagnosis?
Clinical features are variable, understandably, but most patients will present with a palpable enlarging mass. Many intra-abdominal or retroperitoneal sarcomas grow to large sizes prior to diagnosis. It’s commonly quoted that it takes patients on average over one year to be diagnosed.3
What could it be?
The first step is a biopsy. As has been remarked earlier, there is a huge variety of diagnoses. See below for a list of the BONE tumors that are possible. This is why it’s so important to have the sample reviewed by an expert pathologist, as the diagnosis has dramatic implications on the treatment. What distinguishes sarcoma as a family of diagnoses is that it includes mesodermal derivatives, including connective tissue, muscle, and peripheral nerve sheath. These are the building blocks of the body, the scaffold, if you will.
Next Steps/Treatment
See the other posts here for more information regarding treatment and initial staging. Simply put, treatment requires imaging to determine optimal administration of surgery, radiation, and chemotherapy. The treatment for each subtype of sarcoma can vary wildly, and so discussion is best had with a sarcoma expert.
pubmed.ncbi.nlm.nih.gov/30223067
acsjournals.onlinelibrary.wiley.com/doi/10.3322/caac.21763
/www.ncbi.nlm.nih.gov/pmc/articles/PMC3270193/