Madrid, 10 February 2020. 22% of people diagnosed with cancer in Spain have a rare tumour, according to data from the Spanish Orphan and Infrequent Tumours Group (GETHI). In these cases, as with other rare diseases, the main problems are delayed diagnosis, reduced availability of therapeutic options and, above all, the difficulty of finding professionals who are experts in a disease that only affects a small part of the population.
This last aspect becomes crucial in rare tumours such as sarcomas, where a patient's chances of cure depend very much on the health professional's accumulated experience. “If there is even the slightest suspicion of sarcoma, it is important to refer the patient to a centre specialised in the treatment of sarcomas because the first surgery is unrepeatable and the patient risks the majority of his or her prognosis in this first operation,” stresses Dr Ricardo Cubedo, head of the Hereditary Cancer and Sarcomas Unit in MD Anderson Cancer Center Madrid.
As this expert continues, “a standard oncology service may have seen few, if any, cases of a particular type of sarcoma, and in the approach to sarcoma it is essential that the person who diagnoses it under the microscope has diagnosed many, that the person who operates on it has operated on many and that the person who treats it with chemotherapy has already dealt with many previous cases.” In fact, with early detection and a specialised approach to sarcoma, “a patient's life expectancy can be the same as that of a healthy subject,” he notes.
The problem is that early diagnosis of sarcoma is complicated, especially for two reasons: sarcoma usually occurs in young people in whom a tumour is not suspected at first, and there are up to 150 subtypes of sarcoma, which means that there is a very wide variety of very non-specific symptoms that can often be confused with growing pains or sports injuries.
“The truth is, we diagnose patients more advanced than we would like to,” recognises Dr Cubedo, who also explains that “beyond some cases related to previous treatments with radiation therapy, the reasons for the origin of this tumour, which does not seem to have anything to do with lifestyle, are not really known, so it is complicated to recommend prevention guidelines.”
Dr Cubedo recommends going to the specialist if pain appears in children or adolescents that is located on only one side of the body, wakes up at night and lasts more than a month. Another circumstance in which it would be better to go to the specialist would be a pain diagnosed as tendinitis or overload that does not improve after treatment with anti-inflammatory drugs, infiltrations or short wave frequencies, as well as any lump larger than a golf ball in adults or a marble in children. In these cases, the usual procedure is to perform an imaging test to rule out the presence or not of any type of sarcoma.
Osteosarcomas and soft tissue sarcomas
In order to try to improve diagnosis, the scientific community has classified sarcomas into two large groups: osteosarcomas, which originate in the bones, and soft tissue sarcomas, which originate in any part of the body, such as muscles, nerves, tendons, fat, etc. Of the approximately 150 sarcomas that exist, two of the most common are liposarcoma (fat-based) in youth and osteosarcoma in children (preferably starting in the extremities).
Although, as Dr Cubedo points out, the key to curing sarcomas is “optimal surgery in the best hands and with a very well integrated team,” treatments such as chemotherapy or radiation also play an important role in sarcomas, either after surgery as an adjunct to surgery or before surgery in cases where the tumour is unresectable, that is, when it has spread to nearby tissues.
In addition to the usual treatments and despite the fact that research on rare diseases always involves many difficulties, there are several clinical trials currently investigating the effectiveness of new therapies such as immunotherapy or targeted treatments in the treatment of sarcomas.