Screenings For Family Members?

My mom has leiomeiosarcoma, the Dr's say they dont know where it came from or how or why. Of course it is behaving strangely and not responding to normal treatments. It has spread from leg, to abdomen, to lungs now. Her mother died from lung cancer that was attributed to rheumatic fever when she was a child that created scar tissue and 2nd hand smoke. My grandmother's mother also died from lung cancer, which they didnt know til the autopsy. This was also attributed to smoking, which she did for many years. My question is why do the Dr's tell me there is nothing to worry about. There's been 3 generations of women in a direct line to have had cancer of some kind, most of it ending up in the lungs. I am overweight and in grad school so its a little difficult to be as healthy as I would like but none of my Dr's seem concerned that I be screened for anything early. Should I ask about something? I have an HMO so I don't know if they will pay for anything out of the ordinary, also I do not want to suggest that I have cancer and lose my insurance. Im open to suggestions as to what I should do. Thanks and good luck.
Buttercup

The study of the genetics of cancer is in its infancy. It is important to take careful note of family history and get screened early for cancers common in your family. Some of the signs that cancer in a family may be genetic are diagnosis at an early age, more than one primary cancer in individuals, the same or related cancers in more than one generation. You may be told that there is no reported genetic cancer pattern, but just because the pattern of cancer in your family has not been named and written up in a medical journal does not mean that it does not exist.

I have had endometrial cancer, as did my mother and her mother. My sister has had renal cell (kidney) carcinoma, as did our mother, and our mother's brother. Three family members have had two different primary cancers, one has had three different primaries, and other family members have had many other different cancers. We have been told that the cancer in our family does not follow any previously described pattern, but it definitely is inherited in my family. We are checked periodically for kidney cancer, and my daughter will be checked for endometrial cancer beginning at age 30.