# Quality of Life and Clinical Outcomes in Patients with Skull Base Chordoma and Chondrosarcoma Treated with Pencil-Beam Scanning Proton Therapy

## TL;DR

This study examines how proton therapy affects the quality of life and survival of patients with skull base chordoma and chondrosarcoma over the long term.

## Contribution

The study provides the first long-term quality of life analysis for these patients treated with proton therapy.

## Key findings

- Quality of life declines immediately after proton therapy but improves after five years.
- Complete tumor resection before therapy correlates with better quality of life outcomes.
- Gender, resection status, and disease progression significantly affect quality of life.

## Abstract

Understanding of long-term QoL in skull base Ch and ChSa patients following PT is essential due to their relatively long survival. Previous data on this aspect was limited to only one study with a short follow-up period. Our study aims to fill this gap by providing the first analysis of QoL in these patients in a long-term follow-up setting. We correlated the QoL data to oncological outcomes and identified three main factors affecting QoL in this population. Our findings highlight the importance of consideration of QoL in comprehensive patient care and treatment decision-making for skull base chordoma and chondrosarcoma.

Background: skull base chordoma (Ch) and chondrosarcoma (ChSa) are rare neoplasms prone to local relapse. Alongside surgery, proton therapy (PT) is a well-established treatment for them. Given the relatively long patient survival expectancy, post-treatment quality of life (QoL) is crucial. This study prospectively assessed long-term QoL in this collective. Methods: seventy-seven adult patients (median age, 50 years; male n = 31; 40.3%) with skull base Ch/ChSa completed at least two EORTC-QLQ-C30 and BN20 questionnaires during and after PT. Oncological outcomes and therapy-related toxicities were recorded during follow-up. QoL was analyzed, with post-treatment scores compared to each patient’s baseline and correlated to oncological outcomes. Results: median follow-up was 51 months (range, 1–94), with 5-year overall survival (5yOS) and local control (5yLC) rates of 88.8% and 82.8%, respectively. The time to local or distant failure ranged from 8 to 58 (median, 22) months. QoL deteriorated directly at completion of PT and two to three years thereafter, especially in patients with local or distant failure. From the fifth year onward, QoL improved again. Complete resection before PT correlated to better QoL at all time points. Disease progression was associated with overall worse QoL, higher neurological symptoms already before PT, and higher symptom burden one year thereafter. Males reported better QoL before and one year after PT than females. Conclusions: PT achieves excellent OS and LC in patients with skull base Ch/ChSa. QoL declines directly after PT but remains close to reference population values. From the fifth year onward, QoL improves again. Gender, resection status, and disease progression significantly affect QoL in these patients.