Do you need renal biopsy before SBRT for RCC suspicious cancer?   

Yes. The teaching is usually that ≈ 20% of small renal masses (<4 cm) are benign, and this rate goes down as size increases (Thompson et al., PMID 19286217). Features such as contrast enhancement, tumor location, and sex can help to improve the malignant risk potential of these lesions, but...

Rare case to not have or be able to do a biopsy (usually there is significant co-morbidity so makes you question the benefit to the planned radiation therapy). In this case, you mention HCC which would likely need to be treated first as it is likely the more problematic cancer (although there is som...

Interesting question. In the IROCK metaanalysis, 83% of the patients had pathological confirmation. So not everyone requires a biopsy although it is recommended. In cases like this, one can weigh the pros and cons of upfront SABR to the renal mass versus short-term surveillance, especially with a co...