Treating renal cell carcinoma: Cryoablation or partial nephrectomy?

January 1, 2009

In the treatment of renal cell carcinoma, partial nephrectomy produces better quality of life than cryoablation, according to researchers at Washington University, St. Louis.

San Francisco-In the past, there has been an assumption that laparoscopic cryoablation leads to better quality of life (QoL) than laparoscopic partial nephrectomy for the treatment of renal cell carcinoma because of the less invasive nature of cryoablation. This is not necessarily the case, according to researchers at Washington University in St. Louis, who compared outcomes and QoL scores in patients who underwent laparoscopic partial nephrectomy or laparoscopic cryoablation.

Questions about the two procedures' outcomes have received renewed interest in recent years, given the increased incidence of small renal masses (<4 cm in diameter). Clinicians and their patients are faced with a decision over the most appropriate treatment for these tumors.

"I would have assumed that the cryoablation patients had the better quality of life because the procedure is less invasive," said first author Matthew Katz, MD, a minimally invasive urologic oncology at Washington University, working with Sam Bhayani, MD, and colleagues. "Our data does not necessarily support this notion."

The SF-36 is a well-validated instrument used to measure multiple components of physical and mental health, Dr. Katz noted. The survey is broken down into eight domains that are scored from 0 to 100, with higher scores correlating with better function. Typical treatment parameters and outcomes were also recorded for all patients.

'Statistically significant' outcomes

Dr. Katz said the analysis revealed statistically significant differences in treatment outcomes between the two arms. Median tumor size was 2.36 cm in the cryoablation arm versus 2.68 cm for the partial nephrectomy arm. Estimated blood loss for cryoablation patients was 104 mL compared to 301 mL for partial nephrectomy patients. Median operating time for cryoablation was 170 minutes versus 218 minutes for partial nephrectomy. The cryoablation complication rate was 18.3% versus 24.8% for the partial nephrectomy arm.

However, partial nephrectomy produced better QoL, the measure that most directly concerns patients, Dr. Katz reported, although he noted that the differences were not dramatic. When controlling only for baseline QoL, at day 1, partial nephrectomy scores were better in the domains of role limitation due to physical problems (48 vs. 29 for cryoablation); general perception of health (64 vs. 51); energy and vitality (49 vs. 39); and mental health (72 vs. 64). At 3 months, when controlling for baseline QoL only, the partial nephrectomy group scored better in physical functioning (75 vs. 56); role limitation due to emotional problems (83 vs. 66); and mental health (79 vs. 70).

When controlling for baseline QoL and tumor size, age, and ASA, the partial nephrectomy group at day 1 had better scores for general perception of health (63 vs. 54); at 3 months, nephrectomy patients scored higher in physical functioning (70 vs. 61) and had slightly higher pain scores than the cryoablation patients did (1.53 vs. 0.44).

Whether or not the small differences in QoL scores make a practical difference to patients or to surgeons is unclear, said Maxwell Meng, MD, associate professor of urology at the University of California, San Francisco.

"You point out that some of our perceptions with regard to cryoablation and partial nephrectomy are actually misconceptions," Dr. Meng said in discussing the study. "But do a couple of points [in SF-36 scores] translate into a clinical difference? That's the real question that we have to consider here."

It is also a question that the current data cannot answer, Dr. Katz said.

"One significant weakness of this study is the potential for surgeon selection bias," he explained. "A randomized, controlled trial would better answer the questions that we all have about quality of life differences between patients who undergo either laparoscopic cyroablation or partial nephrectomy."