Hybrid Therapy (Surgery and Radiosurgery) for the Treatment of Renal Cell Carcinoma Spinal Metastases

Abstract

BACKGROUND:The management of spinal metastatic renal cell carcinoma (mRCC) is controversial regarding extent of resection and radiation dosing.OBJECTIVE:To determine outcomes in patients treated with hybrid therapy (separation surgery plus adjuvant stereotactic body radiation therapy [SBRT]) for mRCC.METHODS:A retrospective study of a prospectively collected cohort of patients undergoing hybrid therapy for mRCC between 2003 and 2017 was performed. SBRT was delivered as high-dose single-fraction, high-dose hypofractionated, or low-dose hypofractionated. Extent of disease, clinical and operative outcomes, and complications data were collected, and associations with overall survival (OS) and progression-free survival were determined.RESULTS:Ninety patients with mRCC with high-grade epidural spinal cord compression (ESCC grades 2 and 3) were treated. Metastases were widespread, oligometastatic, and solitary in 56%, 33%, and 11% of patients, respectively. SBRT delivered was high-dose single-fraction, high-dose hypofractionated, and low-dose hypofractionated in 24%, 56%, and 20% of patients, respectively. The 1-yr cumulative incidence of major complications was 3.4% (95% confidence interval [CI]: 0.0%-7.2%). The median follow-up was 14.2 mo for the entire cohort and 38.3 mo for survivors. The 1-yr cumulative incidence of progression was 4.6% (95% CI: 0.2%-9.0%), which translates to a local control rate of 95.4% (95% CI: 91.0%-99.8%) 1 yr after surgery. The median OS for the cohort was 14.8 mo.CONCLUSION:These data support the use of hybrid therapy as a safe and effective strategy for the treatment of renal cell spine metastases.

Fifty‐year history of the evolution of spinal metastatic disease management

“…The neurologic and oncologic considerations are combined to optimize the preservation of neurologic function and local tumor control. The role of radiation therapy and surgery has evolved over the past five decades in large part due to the development of sSRS, which provides histology independent, durable tumor control, and has revolutionized the NOMS framework in both the neurologic and oncologic domains 14,16–18 . Prior to the 2000s, cEBRT was the only widely available modality for treating spine metastases 5 .…”

“…Hypofractionated radiation overcomes the radioresistance seen with cEBRT by substantially increasing the biologic equivalent dose, which leads to increased lethal double‐stranded DNA breaks and invokes unique radiobiologic mechanisms such as endothelial apoptosis that is mediated by the acid sphingomyelinase pathway and cytotoxic T‐cell immunogenic responses 19,38,39 . The benefits of sSRS compared to cEBRT include shorter treatment times, delivery of an ablative radiation dose resulting in histology‐independent, durable tumor control, and the ability to safely re‐irradiate those who have failed prior radiation 14,18,22 …”

“…Whereas the indications for surgery have remained unchanged since the publication of the Patchell study, the efficacy of postoperative sSRS has shifted surgical objectives 18,20,22,25 . The improved local control of sSRS allowed for separation surgery, a surgical technique whereby the thecal sac is decompressed and reconstituted to create a 2 mm margin between the tumor and the spinal cord for targeting constraints.…”

“…Over the past 15 years, the development of spine stereotactic radiosurgery (sSRS) has fundamentally changed the treatment paradigm 12–17 . The ability of sSRS to deliver ablative radiation doses that are histology independent changed the indications for and types of surgery required 14,18,19 . The pendulum has swung back toward radiation as the principal treatment modality with surgery used in selective cases as an adjuvant to sSRS for recovery of neurologic function, improvement in radiation target volume coverage within spinal cord dose constraints, and spinal reconstruction 12,20,21 .…”

“…[12][13][14][15][16][17] The ability of sSRS to deliver ablative radiation doses that are histology independent changed the indications for and types of surgery required. 14,18,19 The pendulum has swung back toward radiation as the principal treatment modality with surgery used in selective cases as an adjuvant to sSRS for recovery of neurologic function, improvement in radiation target volume coverage within spinal cord dose constraints, and spinal reconstruction. 12,20,21 Intralesional gross total or en bloc excisions are no longer required and largely have been supplanted by separation surgery to create a safe sSRS target through epidural decompression.…”