Inoperable renal cell carcinoma: Is radiation an alternative?
Surgery is a first choice in primary renal cell carcinoma. Radiotherapy has played a subordinate role, but it could gain importance, as not all tumours are operable.
The study at a glance
- The cohort analysis included 190 patients with stage I renal cell carcinoma from five countries.
- All subjects had received primary SBRT between 2007 and 2018, of which 43% received it as a single-treatment regimen and 57% as a fractionated regimen.
- The follow-up period was at least two years.
- The primary endpoint was local recurrence rate according to RECIST (Response Evaluation Criteria In Solid Tumours) criteria.
After 5 years, the cancer-specific survival was 92%. The progression-free survival in the same period was just under 64%, whereby about three quarters of the total of 66 deaths were not due to the tumour. After all, the median age of the subjects was just under 74 years and they often had comorbidities.
One-time better than fractionated
The study team also found remarkable values with regard to the primary endpoint. For example, the 5-year incidence of local recurrence was just 5.5% - and this in the majority of inoperable patients with relatively large tumours (median diameter 4 cm).
One-time SBRT performed better than fractionated radiotherapy. It was associated with a lower local recurrence rate as well as with a higher progression-free survival compared to multistage SBRT.
GFR is somewhat affected by SBRT
Next, the researchers examined the course of kidney function. Pretherapeutically, the median glomerular filtration rate (eGFR) was 60 ml/min/1.73 m². After five years, it decreased by a median of 14.2 ml/min/1.73 m². However, almost half of the patients had chronic renal insufficiency of grade ≥ 3 (GFR < 60 ml/min per 1.73 m²) before treatment, and almost 30% had a single kidney.
Seven patients (4%) required dialysis during the follow-up period. They also had significantly reduced kidney function before SBRT, with a median eGFR of 33 ml/min per 1.73 m².
Radiation was well tolerated
The side effects of radiotherapy also remained manageable. Only one patient suffered more severe toxicities (duodenal ulcer and gastritis). 70 patients (37%) developed mild toxicities of grade 1-2, mainly fatigue. There was no difference in toxicity rates between single-stage and fractionated radiotherapy.
Conclusion for medical practice
The comprehensive meta-analysis of the International Radiosurgery Consortium of the Kidney (IROCK) provides for the first time reliable long-term data on SBRT for primary renal cell carcinoma. From the researchers' point of view, radiotherapy also proves to be effective and safe in the long term. For patients who are inoperable or refuse surgery, this opens up another treatment option. By contrast to resection, radiotherapy is also a gentle procedure that could be particularly beneficial for older people with comorbidities.
- Siva S, Ali M, Correa RJM et al (2022) 5-year outcomes after stereotactic ablative body radiotherapy for primary renal cell carcinoma: an individual patient data meta-analysis from IROCK (the International Radiosurgery Consortium of the Kidney). Lancet Oncol. 23(12):1508–1516. DOI: 10.1016/S1470-2045(22)00656-8.
- Only German: Rühle A, Kirste S. Vielversprechende Therapieoption insbesondere für ältere und inoperable Patienten. Stereotaktische Strahlentherapie von primären Nierenzellkarzinomen. InFo Hämatologie + Onkologie 2023; 26(3): 28-29. DOI: https://doi.org/10.1007/s15004-023-9857-5.