Proton Radiation Therapy for Nasopharyngeal Cancer Patients: Dosimetric and NTCP Evaluation Supporting Clinical Decision

Abstract

(1) Background: we proposed an integrated strategy to support clinical allocation of nasopharyngeal patients between proton and photon radiotherapy. (2) Methods: intensity-modulated proton therapy (IMPT) plans were optimized for 50 consecutive nasopharyngeal carcinoma (NPC) patients treated with volumetric modulated arc therapy (VMAT), and differences in dose and normal tissue complication probability (ΔNTCPx-p) for 16 models were calculated. Patient eligibility for IMPT was assessed using a model-based selection (MBS) strategy following the results for 7/16 models describing the most clinically relevant endpoints, applying a model-specific ΔNTCPx-p threshold (15% to 5% depending on the severity of the complication) and a composite threshold (35%). In addition, a comprehensive toxicity score (CTS) was defined as the weighted sum of all 16 ΔNTCPx-p, where weights follow a clinical rationale. (3) Results: Dose deviations were in favor of IMPT (ΔDmean ≥ 14% for cord, esophagus, brainstem, and glottic larynx). The risk of toxicity significantly decreased for xerostomia (−12.5%), brain necrosis (−2.3%), mucositis (−3.2%), tinnitus (−8.6%), hypothyroidism (−9.3%), and trismus (−5.4%). There were 40% of the patients that resulted as eligible for IMPT, with a greater advantage for T3–T4 staging. Significantly different CTS were observed in patients qualifying for IMPT. (4) Conclusions: The MBS strategy successfully drives the clinical identification of NPC patients, who are most likely to benefit from IMPT. CTS summarizes well the expected global gain.

Radiotherapy with Helium Ions Has the Potential to Improve Both Endocrine and Neurocognitive Outcome in Pediatric Patients with Ependymoma

“…By inserting parameters which represent the potential biological damage caused by irradiation the patient specific risk for long-term side effects can be calculated [ 21 ]. In fact, NTCPs are expected to become gold standard for identifying the patients likely to benefit most from particle therapy [ 22 ]. Due to its limited availability and its high treatment costs, it is very important to define strategies for clinical decision making.…”

Acute radiation dermatitis among patients with nasopharyngeal carcinoma treated with proton beam therapy: Prognostic factors and treatment outcomes

“…A variety of ARD severity exists in the literature and our cohort for NPC patients treated with PBT or XRT. The proportion of patients with grade 1, 2 and 3 ARD after treatment with PBT was 0-64.3%, 25-67.4%, and 3.6-42.0%, respectively [3,4,14,20]. For XRT, it varies from 6.4-51.0% for grade 1, 31-69% for grade 2, and 8.8-23.6% for grade3 in selected reports [21][22][23][24].…”

The Normal, the Radiosensitive, and the Ataxic in the Era of Precision Radiotherapy: A Narrative Review

“…NTCP models are currently used in clinical practice to optimize the planning of treatments and to guide the dose distribution in order to reach the optimal balance between Tumor Control Probability and the risk of toxicities. They can also assist the clinician in decision-making, e.g., selecting patients who would benefit the most from advanced RT techniques (rather than conventional radiotherapy), such as proton therapy, through a comparison of competing options for radiotherapy plans [ 42 ].…”