Diagnostic Radiation Exposure During Surveillance in Patients With pT1a Renal Cell Carcinoma

Abstract

To determine the pattern of postoperative radiographic surveillance in patients with pT1a renal cell carcinoma (RCC) at a tertiary care hospital. An institutionally approved urologic oncology database was used to retrospectively identify patients who underwent partial or radical nephrectomy for pT1a RCC from 1990 to 2010 at a tertiary care center. Baseline characteristics were reviewed, and postoperative imaging for the indication of RCC surveillance was recorded. Radiation exposure was calculated using the effective dose according to imaging modality. Relative risks of the development of solid malignancies and leukemia were calculated from the dose of radiation exposure. RCC recurrence, defined as radiologic evidence of local recurrence or distant metastases, was noted. A total of 1708 patients had undergone partial or radical nephrectomy for a renal mass. Of these, 315 patients had pT1a RCC with postsurgical follow-up, and 252 (80%) of these patients were exposed to ionizing radiation during postoperative surveillance. Mean radiation doses in years 1, 2 to 5, and≥6 after surgery were 11.4, 47.0, and 13.8 mSv, respectively. Relative risks of radiation-induced solid cancers and leukemia were 1.05 and 1.12, respectively. There were 8 (2.5%) total recurrences. During the past 20 years, 80% of patients undergoing surgery for pT1a RCC were monitored with radiation-based imaging during postoperative surveillance. Given the low rate of cancer recurrence in this population, expanded efforts in counseling physicians regarding the risk of ionizing radiation in imaging should be encouraged.