Stereotactic radiotherapy a viable treatment option for solitary kidney tumours
Stereotactic ablative radiotherapy has shown its capability as a treatment option in patients with renal cell carcinoma in a solitary kidney, achieving excellent oncologic outcomes as well as having an acceptable impact on renal function, according to an analysis of the IROCK (International Radiosurgery Oncology Consortium for Kidney) database.
Eighty-one patients (mean age, 67.3 years; median tumour diameter, 3.7 cm, IQR, 2.5–4.3; 37 percent of tumours were ≥4cm) with a solitary kidney underwent stereotactic ablative radiotherapy, of whom 97.5 percent had good performance status, including ECOG (Eastern Cooperative Oncology Group) 0-1 or KPS (Karnofsky Performance Status) ≥70 percent.
Patients (n=138) in the bilateral kidney cohort had larger tumours and were older (p<0.001), with a lower baseline estimated glomerular filtration rate (eGFR; p=0.024).
After stereotactic radiotherapy in the solitary kidney cohort, patients had a mean estimated eGFR decrease of –5.8±10.8 ml per minute (–9 percent), and none of them required dialysis. Furthermore, a tumour size of ≥4 cm correlated with an eGFR decrease of ≥15 ml per minute (odds ratio, 4.2; p=0.029).
The rate of local control at 2 years was 98.0 percent, while progression-free, cancer-specific and overall survival rates were 77.5 percent, 98.2 percent and 81.5 percent, respectively. No significant between-group difference was observed in renal function or oncologic outcomes (p>0.05).
This study pooled individual patient data from nine IROCK institutions in Germany Australia, Japan, Canada and US, with a median follow-up of 2.6 years. The authors compared baseline characteristics and outcomes between the solitary and bilateral kidney cohorts. Logistic regression modeling was used to assess the predictors of renal function after stereotactic radiotherapy.