Quality of life after proton beam therapy in childhood - early results
Last Modified: June 10, 2013
Presenting Author: B. Timmermann, MD
Presenting Author Affiliation: Essen University Hospital, Westgerman Proton Therapy Centre, Essen, Germany
- Improving quality of life (QoL) after cancer care is a major aim when adapting modern therapy concepts.
- Proton therapy (PT) is of special interest in childhood cancer diseases to potentially reduce treatment burden. However, data on QoL after PT are scarce.
- PSI established a collaboration with the PEDQOL Study to enable prospective evaluation of QoL in children receiving PT.
Materials and Methods
- The pilot phase started in 2005 and evaluation ended in December 2010.
- According to age, either PEDQOL or PedsQL forms were handed out before PT, 2 months and yearly thereafter from years 1-5.
- In total, 142 children were included aged between 1-19 years (mean 6.2 years).
- Diagnoses were CNS tumor (n=53), soft tissue sarcoma (n=45), bone tumor (n=12), chordoma/low grade chondrosarcoma (n=11) and miscellaneous (n=21).
- In 84 children (59%) at least one physical deficit was reported before onset of PT.
- The most common deficits were vision (37), motor skills disorder (34), and cranial nerve palsy (31).
- In 120 children, Karnofsky performance scale before PT was exceeding 80%.
- 123 children had received at least one previous treatment modality, the most common of which was chemotherapy (105).
- Applied PT dose ranged from 36 to76 Gy (mean 55.6 Gy and median 54 Gy).
- In total, 626 questionnaires were completed and analyzed. Results were compared to a normal reference group (NG).
- QoL before PT was equal to NG by children themselves above 4 years of age. In contrast, their parents reported the QoL before PT slightly inferior to NG.
- QoL for children below 4 years of age before PT was reported to be significantly inferior to NG in all domains.
- When comparing QoL before PT to QoL after 2 months and 1 year, no drop in QoL was observed for any age group. This included the PEDQOL report in patients >4 yo and the PedsQL proxy report in patients less than 4.
- Proton therapy offers clear dosimetric advantages over photon therapy in the pediatric population.
- Maintaining high QoL and limiting severe adverse events after cancer treatment are important goals in pediatric oncology.
- Presented early data suggest that even after intensive local proton beam treatment, QoL was fully preserved. This included even the very young patients.
- Data will need to be confirmed after longer follow up and in larger cohorts.
- This was a very large, prospective study showing data proving the hypothesis that proton beam therapy, due to its decreased integral dose, may not decrease pediatric quality of life.
- Approximately half of these patients had CNS malignancies; neurocognitive effects after CNS radiation are related to dose, volume, and patient age (Mulhern Lancet Oncol 2004, Merchant JCO 2009). Proton beam therapy, due to its highly conformal SOBP, has the potential to improve these outcomes.
- A secondary observation of this study was that parents do not have the same QoL assessment as children < 4. Therefore, it is important to continue to measure both parent and child assessments in patients <4 and to determine which best correlates with long-term QoL.
- An interesting additional study would be a matched cohort study with patients who receive photon therapy; the presenter noted that while this would be an ideal study to assess for the QOL benefits specific to proton therapy, it may be a difficult study because most children, particularly those <4 yo, now receive proton therapy. Therefore, it would be difficult to find matched photon patients treated similarly in the modern era.
- In the final report of this study, it will be important to see the specific questions asked in the PEDQOL questionnaire and if this has been prospectively validated. We will also await long-term follow up to assess for comorbidities and second malignancies.