Findings and Impact of Early Imaging After Partial Nephrectomy

American Urological Association guidelines for surveillance of renal-cell carcinoma after partial nephrectomy recommend imaging within 3-12 months of surgery. Imaging following partial nephrectomy may be difficult to interpret due to the surgical defect, the use of surgical material, and normal postoperative fluid collections. Our primary objective was to evaluate the frequency of indeterminate postoperative imaging results and how those radiographic findings altered patient management. Retrospective chart review from 2006 to 2013 of patients who had undergone open, laparoscopic, and robotic partial nephrectomy at our institution was completed. There was a minimum of 2 years of follow-up imaging. Radiology reports were reviewed from follow-up imaging and were categorized as "normal" or "abnormal." We identified 180 patients with 127 (70.5%) considered to have normal findings on initial follow-up imaging, and 53 (29.5%) with abnormal findings. Median time to initial postoperative imaging for normal findings was 6.8 months compared with 4.4 months for patients with abnormal postoperative scans (p = 0.02). On subsequent imaging, 60% of abnormal studies were downgraded to normal. The median time to receive a second postoperative image from surgery in the normal and abnormal groups was 13.2 and 10.2 months, respectively. The median time interval to the second imaging study was 6.3 months for normal initial scans compared with 5.2 months for initially abnormal scans (p ≤ 0.01). Early postoperative imaging after partial nephrectomy frequently results in "abnormal" findings and more subsequent radiology exams even though the findings rarely represent cancer recurrences. Based on our results, and pending further validation from other centers, we believe postoperative CT or MRI surveillance after partial nephrectomy can be safely deferred until 1 year after surgery.