Investigation of the safety and accuracy of intraoperative gamma probe directed biopsy of bone scan detected rib abnormalities in prostatic adenocarcinoma.

Purpose: We evaluated the technique of intraoperative gamma probe directed rib biopsy in patients with suspected metastatic prostate adenocarcinoma. This technique can be used to identify accurately the rib in question, reliably obtain sufficient tissue for diagnosis, be performed with minimal patient morbidity and potentially alter the course of therapy.

Materials And Methods: From 1996 to 2001, 8 patients with biopsy proved adenocarcinoma of the prostate and suspicious rib lesions on radionuclide bone scanning underwent open rib biopsy as part of the evaluation for metastatic disease. Mean prostate specific antigen in the patient population was 17.1 ng/ml (range 6.1 to 36.5) and clinical stage was T1c to T3c. A new technique of intraoperative gamma probe directed biopsy was used to localize and resect the rib in question. At 6 to 12 hours before the operation each patient received an intravenous injection of 28 mCi. (99m)technetium-oxidronate. The hand held, pencil sized gamma probe in a sterile sleeve was used to localize the area of greatest activity in the target bone and 3 cm. of bone were resected.

Results: Of the 8 patients who underwent the procedure 2 had metastatic prostate cancer on final rib pathological findings. Four of the remaining 5 patients had benign rib lesions (an old rib fracture) and 1 had metastatic lung cancer. The hot spot on bone scan was localized with 100% accuracy using our technique and a pathological diagnosis was made in all cases. Mean operative time was 61 minutes and estimated blood loss was less than 20 ml. in all cases. Seven of the 8 patients were discharged home the same day, while 1 required overnight hospitalization. There was 1 intraoperative complication of inadvertent entry into the pleural cavity, resulting in a small pneumothorax, which was treated with small chest catheter drainage and observation.

Conclusions: Intraoperative gamma probe directed rib biopsy of suspected metastatic lesions in patients with prostate cancer can be safely and accurately performed with minimal patient morbidity. The information obtained using this technique can be used to tailor treatment decisions for this subset of patients with prostate cancer.