Clinical correlation of previously undetected cancer-related incidental findings on CT planning scans for radiation therapy

OBJECTIVE. The purpose of our study was to determine the management and cancer outcome of incidental cancer-related findings reported on CT radiation treatment planning scans. MATERIALS AND METHODS. We conducted a retrospective review of CT planning scans performed from 2004 to 2006 with diagnostic radiology reports. We previously found 45 (8%) cancer-related findings, defined as any previously unknown radiologic finding that could potentially change the staging or treatment of the cancer, in the 580 CT scans reviewed. This study further examines the cancer-related findings to identify their clinical significance, management, and cancer outcomes. RESULTS. Eight (18%) of the 45 cancer-related findings prompted additional imaging, with negative findings and no cancer failure at the site of the cancer-related findings. Three (7%) cancer-related findings resulted in changes in cancer management without further imaging, including initiating induction chemotherapy instead of localized radiation, increasing the radiation dose to identified lymphadenopathy, and changing the sequence of local management to initial surgery followed by radiation. Two of these findings had local recurrence at the site of cancer-related findings. The remaining 34 (76%) cancer-related findings did not result in any additional action. With a median follow-up of 17 months (range, 2-67 months) from CT, there was a similar failure rate at the site of cancer-related findings in the groups without (15%) and with (18%) additional action. CONCLUSION. In our series, cancer-related findings identified by diagnostic radiology review of radiation planning CT scans are associated with low incidence of cancer management changes and disease progression. However, the generalizability of this study is unclear because of the small number of cancer-related findings present.