Stereotactic body radiation therapy shows promising results in frail patients and oligometastatic cases, offering potential for curative approach and delaying systemic therapy
Renal cancer has been considered a radioresistant tumor until recent advancements in radiation oncology. New techniques, such as stereotactic body radiation therapy (SBRT) allow for the safe and precise administration of high-dose radiation in a limited number of fractions, producing a different biological effect than conventional radiotherapy. A study in the International Journal of Urology reviewed renal SBRT in primary tumors and metastases.
Primary Renal Cancer
- Indications and Results
Surgery is the treatment of choice for localized renal cancer. However, factors such as patient comorbidities, tumor characteristics (e.g., size >4cm, closeness to the renal pelvis), renal function, or frailty can make surgery unfeasible. SBRT, a non-invasive technique, is an alternative treatment option for patients unfit for surgery. It is recommended in patients with a performance status <2, creatinine clearance in >25–30 ml/min, and no specific age or tumor size limit.
SBRT for primary renal tumors shows promising results. Studies show good local control and overall survival with a favorable safety profile. However, the available data is limited.
- Comparison With Other Treatments
There are no randomized studies comparing SBRT and surgery or ablative therapies in localized renal cancer. Two retrospective studies showed that SBRT had worse results for overall survival than surgery. Ongoing clinical trials are evaluating SBRT as a therapeutic option for suitable candidates.
Renal Oligometastases
- Indications and Results
Oligometastasis is defined as the presence of five or fewer metastatic lesions with a controlled primary tumor. Local treatment of these metastases improves survival in these patients. A phase II trial has reported improvements in overall and progression-free survival in oligometastatic patients who were randomized between a control arm with a palliative standard of care and a stereotactic ablative body radiotherapy (SABR) arm with SABR to all metastases.
SBRT can be used in oligometastatic patients who are not surgical candidates. Local ablative therapies can improve quality of life in cases of oligoprogression and oligopersistent disease with the continuation of systemic therapy. Studies regarding SBRT for oligometastases have shown satisfactory local control rates that can impact overall survival with minimal toxicity.
- Comparison With Other Treatments
SBRT of different sites in metastatic disease has been reported to have favorable results. However, no recommendations can be made regarding the best treatment modality based on the existing data. The combination of SBRT with immunotherapy and cytoreductive SBRT are promising strategies for metastatic renal cancer.
Source
Sosa-Fajardo, P., Blanco-Suarez, J. M., Pineda-Munguía, Á., Rubí-Olea, L., Peleteiro-Higuero, P., Gajate, P., Zafra-Martín, J., Siva, S., Bossi, A., López-Campos, F., & Couñago, F. (2023). Stereotactic body radiation therapy for kidney cancer. Where do we stand? International Journal of Urology, 30(5), 437–445. https://doi.org/10.1111/iju.15156
