Reporting and Handling of Indeterminate Bone Scan Results in the Staging of Prostate Cancer: A Systematic Review.

Bone scintigraphy is key in imaging skeletal metastases in newly diagnosed prostate cancer. Unfortunately, a notable proportion of scans are not readily classified as positive or negative but deemed indeterminate. The extent of reporting of indeterminate bone scans and how such scans are handled in clinical trials are not known. A systematic review was conducted using electronic databases up to October 2016. The main outcome of interest was the reporting of indeterminate bone scans, analyses of how such scans were managed, and exploratory analyses of the association of study characteristics and the reporting of indeterminate bone scan results. Seventy-four eligible clinical trials were identified. The trials were mostly retrospective (85%), observational (95%), large trials (median 195 patients) from five continents published over four decades. The majority of studies had university affiliation (72%), and an author with imaging background (685). Forty-five studies (61%) reported an indeterminate option for the bone scan and 23 studies reported the proportion of indeterminate scans (median 11.4%). Most trials (44/45, 98%) reported how to handle indeterminate scans. Most trials (