First Ever Use of Proton Stereotactic Body Radiation Therapy Delivered with Curative Intent to Bilateral Synchronous Primary Renal Cell Carcinomas

Abstract

Limited therapeutic options exist for inoperable bilateral kidney tumors. We report the first ever use of proton therapy to treat primary renal cell carcinoma (RCC) and the first report of proton stereotactic body radiation therapy (SBRT) for RCC in an inoperable patient with synchronous RCCs treated with proton SBRT. The patient is a 47-year-old 450-pound female with multiple medical comorbidities, including Stage 3 chronic kidney disease (CKD), who was found to have bilateral renal masses during work-up for cellulitis and sepsis. Following resolution of her sepsis, subsequent cross-sectional imaging demonstrated interval growth of the left renal mass to 4.4 x 4.8 cm and the right renal mass to 2.0 x 2.6 cm. Bilateral biopsies were performed, with pathology revealing Furhman Grade 1-2 clear cell RCC on both sides. A customized SBRT plan delivered a total dose of 3,000 cGy in five fractions to the bilateral kidneys every other day using proton beam therapy. The patient experienced no grade > 1 acute adverse toxicities from proton therapy, and now at one year after treatment, she has had no clinical symptoms of late radiation-induced toxicities. Although a marginal decline in post-treatment glomerular filtration rate (GFR) was observed (baseline 34 mL/min/1.73m2, one-year post-SBRT 29 mL/min/1.73m2), the patient remains asymptomatic and without a requirement for intervention. In presenting a case in which proton SBRT was performed safely and effectively for a medically complex patient with inoperable synchronous bilateral RCC, we suggest that proton therapy is a promising therapeutic approach for even unilateral primary RCC where preservation of renal function is of importance and should be considered for medically inoperable patients. Further experience is needed to determine the optimal dose and fractionation regimen for renal SBRT with proton therapy.

Sarcomatoid renal cell carcinoma: biology, natural history and management

“…A 2017 case report about a patient with an inoperable RCC, owing to morbid obesity and multiple comorbidities, is the only published instance of proton therapy for a primary RCC. Although a decline in glomerular filtration rate was observed from 34 ml/min/1.73 m 2 to 29 ml/min/1.73 m 2 , no clinical symptoms of late radiation-induced toxic effects were observed and the patient had remained asymptomatic by the last follow-up point of 1 year 142 . This is a hypothesis-generating report, but it remains a single-institution case report and further research is required to determine whether proton therapy is appropriate in both RCCs and sRCCs.…”

Comparison of Combination Stereotactic Body Radiotherapy Plus High-Intensity Focused Ultrasound Ablation Versus Stereotactic Body Radiotherapy Alone for Massive Hepatocellular Carcinoma

“…In SBRT, high doses of photon beam radiation are delivered to the target lesion, causing ionization of water molecules to produce reactive oxygen species, which in turn elicits DNA and cellular damage. Tumor cells are less efficient than normal cells in repairing radiation-induced damage, leading to the preferential destruction of malignant cells [22].…”

Managing treatment-related uncertainties in proton beam radiotherapy for gastrointestinal cancers

“…4D RO typically relies on matching the delivered proton spots to a specific target location or 4D-CT phase (77) or on the assumption that the interplay effect will be averaged out over the delivery of many fractions (39). However, matching a specific delivery to specific tumor motion is technically difficult to implement; fraction averaging breaks down for hypo-fractionated treatments [i.e., stereotactic body proton therapy (78,79)], and the 4D dynamic dose (hence the interplay effect) are only potentially evaluated post optimization. Consequently, some investigators have taken the approach to directly include the treatment temporal dependences and optimize on the 4D dynamic dose itself, i.e., dynamic 4D RO (d4D RO).…”