ABSTRACT
Papillary renal cell carcinoma (PRCC) is a less common subtype of kidney cancer and is typically more resistant to systemic treatments. This report describes a patient with metastatic type II PRCC who experienced two complete responses (CR) to the tyrosine kinase inhibitor (TKI) sunitinib. The patient remains on sunitinib with durable control of the disease. To the best of our knowledge, this is the first case of metastatic type II PRCC with CR to sunitinib.
ABSTRACT
PURPOSE: Our purpose was to evaluate the incidence of acute and late esophageal toxicity in patients with thoracic tumors near or abutting the esophagus treated with SABR. METHODS AND MATERIALS: Among patients with thoracic tumors treated with SABR, we identified those with tumors near or abutting the esophagus. Using the linear-quadratic model with an α/ß ratio of 10, we determined the correlation between dosimetric parameters and esophageal toxicity graded using the Common Terminology Criteria for Adverse Events, version 5.0. RESULTS: Out of 2200 patients treated with thoracic SABR, 767 patients were analyzable for esophageal dosimetry. We identified 55 patients with tumors near the esophagus (52 evaluable for esophagitis grade) and 28 with planning target volume (PTV) overlapping the esophagus. Dose gradients across the esophagus were consistently sharp. Median follow-up and overall survival were 16 and 23 months, respectively. Thirteen patients (25%) developed temporary grade 2 acute esophageal toxicity, 11 (85%) of whom had PTV overlapping the esophagus. Symptoms resolved within 1 to 3 months in 12 patients and 6 months in all patients. No grade 3 to 5 toxicity was observed. Only 3 patients (6%) developed late or persistent grade 2 dysphagia or dyspepsia of uncertain relationship to SABR. The cumulative incidence of acute esophagitis was 15% and 25% at 14 and 60 days, respectively. Acute toxicity correlated on univariate analysis with esophageal Dmax, D1cc, D2cc, Dmax/Dprescription, and whether the PTV was overlapping the esophagus. Esophageal Dmax (BED10) <62 Gy, D1cc (BED10) <48 Gy, D2cc (BED10) <43 Gy, and Dmax/Dprescription <85% were associated with <20% risk of grade 2 acute esophagitis. Only 2 local recurrences occurred. CONCLUSIONS: Although 25% of patients with tumors near the esophagus developed acute esophagitis (39% of those with PTV overlapping the esophagus), these toxicities were all grade 2 and all temporary. This suggests the safety and efficacy of thoracic SABR for tumors near or abutting the esophagus when treating with high conformity and sharp dose gradients.
