Only specialists. Most doctors do not see that many patients with sarcoma, only those doctors (surgeons and others) who specialize in the treatment of sarcomas.
Depends . Sarcomas are rare compared to the much more common carcinoma so in general doctors see and diagnose them less commonly. There are specialists that spend their entire day either diagnosing or treating patients with sarcoma, however, so it varies. .
Only some doctors. There are only a few thousand cases of sarcoma a year in the US, where the population is almost 320 million. Most doctors will see only a few patients with a sarcoma in their career. It is important to have sarcoma treated by a specialist who has experience in this rare cancer as wrong treatment may end up in loss of limb and even life.