Radiotherapy for Aggressive Fibromatosis: The Association Between Local Control and Age

Publication date: Available online 21 December 2017
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): James E. Bates, Christopher G. Morris, Nicole M. Iovino, Michael Rutenberg, Robert A. Zlotecki, C. Parker Gibbs, Mark Scarborough, Daniel J. Indelicato
PurposeRadiotherapy is often used in the treatment of unresectable or recurrent aggressive fibromatosis (also known as desmoid tumor) typically with excellent local control. Prior reports have suggested that local control in pediatric patients with aggressive fibromatosis is poor. We aimed to report a long-term single-institution experience with the radiotherapeutic treatment of these tumors with a focus on age-dependent outcomes.Methods and MaterialsA total of 101 patients treated with radiotherapy for aggressive fibromatosis between 1975 and 2015 at a single institution were identified. A variety of demographic and treatment related variables were abstracted from patients' medical records. Kaplan-Meier analyses were performed to investigate the relationship between these variables and local control.ResultsOverall survival was excellent (98% and 95% at 5 and 10 years); local control was likewise excellent (82% and 78% at 5 and 10 years). Patients ≤20 years at diagnosis had significantly worse 5-year local control compared to those over the age of 40 at diagnosis (72% vs 97%; HR = 9.0; p = 0.009). Those treated with once-daily fractionation had significantly improved 5-year local control compared to those treated with twice-daily fractionation (90% vs 73%; HR = 0.3; p = 0.008). Neither the presence of gross versus microscopic residual disease, initial versus recurrent presentation, number of prior surgeries, nor tumor size had any effect on 5-year local control. A total of 36.6% of patients developed CTCAE grade 3 or 4 toxicity following treatment; the frequency of toxicities was reduced in those treated after 1995 (24.5%) relative to those treated prior to 1995 (51.9%, p=0.02).ConclusionsRadiotherapy for aggressive fibromatosis offers excellent local control and should remain the standard of care for patients with unresectable or recurrent disease. Younger patients have diminished local control relative to older patients, suggesting possible biologic differences contributing to radioresistance in the pediatric and young adult population.

Teaser

Radiotherapy is used in the treatment of unresectable or recurrent aggressive fibromatosis; prior data suggests that local control may be diminished in younger patients. We analyzed a single-institution experience of patients treated with radiotherapy for aggressive fibromatosis over 4 decades. Patients 20 years or under at diagnosis experience diminished local control following radiotherapy compared with patients over 40 years old at diagnosis, suggesting possible biologic differences between tumors in these age groups.


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