Active surveillance of small kidney masses is a safe and effective alternative to immediate surgery, with similar overall and cancer-specific survival rates, according to a study published in the November issue of the urology journal BJUI. The technique is primarily used to treat elderly patients who have complex health issues or decline surgery. But researchers from the Department of Urology at Churchill Hospital, Oxford, UK, say that the results of their study suggest that active surveillance could safely be extended to other selected patients.

"The incidence of kidney cancer has been increasing in Europe and the U.S.A. since the 1980s and the use of more sophisticated imaging techniques means that smaller masses of less than four cm are being picked up at earlier stages," says lead author Dr Nilay Patel. "This has led to an increased rate of surgery for small kidney masses, but the benefits of this remain unclear. Conflicting reports on improvements in death rates for kidney cancer over the last few years suggest that increased detection may not necessarily be improving survival rates for patients with smaller tumours inside their kidney," states Patel.

A total of 202 patients with 234 small renal masses of less than four centimeters inside their kidney - classified as T1a – were identified. Ninety were managed with partial nephrectomy (where only the diseased part of the kidney is removed), 41 with a radical nephrectomy (where the entire kidney is removed) and 71 with active surveillance (where patients are monitored for disease progression). Key findings included:

  • Over a median follow-up of 34 months, the mean growth rate of the kidney masses in patients who were under active surveillance was 0.21cm. However, 53 percent of the small renal masses in these patients showed negative or zero growth.
  • No statistically significant differences were observed in overall and cancer-specific survival rates for patients who were under active surveillance or received partial or radical nephrectomy.
  • The overall survival rates were 83 percent for active surveillance, 80 percent for radical nephrectomy and 90 percent for partial nephrectomy.
  • The cancer specific survival rates were 99 percent for active surveillance, 93 percent for radical nephrectomy and 97 percent for partial nephrectomy.

"Our research suggests that active surveillance of small kidney masses offers similar cancer outcomes to radical or partial surgery in the short and intermediate term" says Dr Patel. "The results of this study support the need for a multi-center, prospective randomised trial to compare how active surveillance and surgery compare when it comes to managing such patients."