Is diagnostic review of radiotherapy-planning CT scans important in the conformal therapy era?

Detailed CT scans are often acquired during the radiotherapy planning process. This study was performed to determine the incidence of important benign and cancer-related CT findings on these scans.

From December 1998 to December 2000, 162 radiotherapy patients who were to be treated curatively underwent treatment planning CT scans on a helical scanner in the radiology department at Washington Hospital, Fremont, CA. All CT scans were prospectively interpreted relative to diagnoses, and reports were dictated for the medical records. The diagnostic reports and records on all patients were reviewed to determine the incidence of previously unknown benign or cancer-related findings, the impacts of such findings on treatment, and the need for additional radiologic studies or procedures on the basis of the CT interpretations.

Incidental benign findings were noted for 32 patients (20%). Potentially important benign findings were noted for three patients: two with aneurysms and one with a possible deep vein thrombosis. Potentially cancer-related findings were reported in 20 patients: a single liver lesion (four patients), multiple liver lesions (two patients), possible or probable lymphadenopathy (11 patients), abnormal soft tissue (one patient), a small-bowel obstruction (one patient), and a breast mass (one patient). After reviewing prior diagnostic studies and obtaining additional recommended studies, the physicians found that only three of the previously unknown findings required further investigation: two aneurysms, which did not require near-term treatment, and one metastatic neck node.

Routine diagnostic interpretation of radiotherapy planning scans resulted in few important medical findings and changed patient care for less than 1% of the patients.