Second Look: Intraoperative sonography aids surgical management in cancerous kidney cell removal

Utilizing ultrasound technology during removal of cancerous kidney segments has been shown to increase the chance of detecting findings not seen during preoperative imaging, according to a study published online this month in the American Journal of Roentgenology.

Researchers studied 198 patients undergoing intraoperative ultrasound (IOUS) during open partial nephrectomy for renal cell cancer.

Of these patients, 21 (10.6 percent) had additional findings on IOUS that were not seen prior to surgery. Fifteen patients with additional findings (71.4 percent) had surgical modifications as a result of the IOUS imaging—seven because of the detection of multifocal tumor and eight because of other findings suggestive of invasive malignancy.

“The primary objective of our study was to determine whether changes in surgical management were made because of findings discovered with IOUS,” wrote lead author Priya R. Bhosale, MD, of MD Anderson Cancer Center in Houston, and colleagues.

The study’s second objective, according to its authors, was to identify incidences of local and distant recurrences after IOUS-guided partial kidney removal and to measure five-year overall survival rates and event free-survival rates of patients.

During the study, IOUS procedures were performed by four radiologists who were not blinded to preoperative CT or MRI findings. The transducers used by the IOUS radiologists were placed directly on the renal surface and the primary tumor was documented for size, vascular supply and its relationship to major blood vessels. Tumor boundaries were marked on the renal capsular surface and the entire kidney was imaged from the upper pole to the lower pole and additional cystic or solid lesions were documented. The entire procedure lasted between 15 and 20 minutes.

When the study concluded in 2012, 161 of the original 198 patients were still alive. The five-year overall and event free-survival rates for the entire study population were high—81 percent and 76 percent, respectively.

“The goal of surgery in renal cancers localized to the kidney is to obtain an adequate tumor-free margin to prevent recurrence, while preserving nephrons and therefore renal function,” wrote Bhosale and colleagues.

Although CT and MRI scans before surgery show the proximity of a tumor to renal structures, real-time imaging like IOUS helps determine whether the distance between a main or segmental blood vessel and the tumor is greater than 3 to 5 mm, making partial nephrectomy possible.

While open partial nephrectomy is currently the standard for treating small renal masses, study authors stated that IOUS is not commonly used for the procedure.

“One likely reason may be that the urology department is not accepting of IOUS and is very hesitant to collaborate with the radiology department,” Bhosale and colleagues wrote.

Another reason, according to the authors, could be the unwillingness of radiology practices to allocate resources to IOUS because of lack of training.

“However, IOUS requires only 15-20 minutes of intraoperative scanning, minimizing the radiologist’s time away from the imaging department and commonly available ultrasound equipment is required,” they said.