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Question 4#

Which one of the following statements regarding active surveillance of T1a small renal masses is CORRECT?

A. Active surveillance is the recommended treatment of choice for low grade
B. Clear cell renal cell carcinoma
C. Malignant tumours can grow at a faster rate than benign lesions
D. The risk of metastatic progression on active surveillance is the same as for all other treatment options
E. Masses have an average annual growth rate of 0.75 cm/year

Correct Answer is C

Comment:

Answer C

Active surveillance has traditionally been reserved for the treatment of T1 small renal masses in elderly patients with multiple co-morbidities or those who decline surgery. The current guidelines for the treatment of T1 renal cancer from the American Urological Association (AUA) and the European Association of Urology (EAU) both propose partial nephrectomy as the gold standard treatment option in the surgically fit patient.

A number of studies have shown that on average benign oncocytomas grow at the same rate as RCC.

Metastatic progression rates for T1a SRMs managed with AS are reported to be between 1% and 2%. Kunkle et al performed a meta-analysis of oncologic outcomes for over 6,000 SRMs and concluded that no statistically significant differences were detected in the incidence of metastatic progression regardless of whether lesions were excised, ablated or observed [6]. A meta-analysis of active surveillance for SRMs revealed a mean growth rate of 0.28 cm/year at a mean follow up of 34 months. Data from a pooled analysis by Smaldone et al demonstrated that T1a tumours have a growth rate of 0.31 cm/year [7]. Jewett et al. noted an annual growth rate of 0.13 cm/year for T1a masses in the prospective Canadian Small Renal Mass Trial.

Numerous studies have previously demonstrated a degree of variability in growth rates of T1 renal masses. Studies have demonstrated that 23%–36% of T1 SRMs have zero or negative growth rates. The pooled analysis of 880 patients with SRMs by Smaldone et al observed that metastatic progression was not observed in any patient who had negative or zero growth on follow-up, which is of great importance when counselling patients being managed with AS.