Aspiration of atypical cyst or surgery?

When I had a CT scan for possible diverticulitis, a 5.7cm cyst was found on my kidney (I weigh 117lb, 5ft tall). The Urologist said it was an atypical cyst with some calcification. He recommended surgery and he indicated that part of my kidney would be removed as well as the cyst. I do not have the normal symptoms for cancer, i.e. weight loss (actually have gained about 5 lbs), night sweats, pain, fever, etc. He didn't take any blood tests or even ask for urine, but I left a sample in the little door anyway. He said that a biopsy wouldn't be effective in determining if there is cancer. Questions: Can I have the cyst aspired instead of full surgery? Would a PET test tell me if I have kidney cancer? If I can't have the cyst aspirated and do need full surgery, would it needlessly exacerbate the problem by waiting to have the surgery until the first part of Sept.? I plan to also consult a Nephrologist as soon as I can make an appointment.