Part of the reason insurance is low is that the pain and suffering component of medical malpractice damages ceases at the death of the patient.
Thus if you a doctor makes an error and you suffer the pain of living with one less arm, you can calculate damages for pain and suffering from the date of the malpractice to the estimated time of your death.
If you're 25, your doctor causes malpractice, you take him to court, and you die in the meantime at age 26, then your pain and suffering damages will only cover one year of life.
This is one of the main reasons the eldery and soon to die have enormous difficulties finding malpractice lawyers. The defense can usually stall (and it does try) until the patient dies in order to lower pain and suffering damages.
In rad-onc most of the patients don't have long to live if the rad-oncologist makes a mistake. While it won't eliminate damages, you won't see the 8 figure damages you see for plaintiffs with 60 years of life left.