Long-term effect and prognostic factors of alow-dose radiotherapy of painful plantar calcaneal spurs : Aretrospective unicenter study.

Abstract

To estimate the long-term effect of low-dose radiotherapy of painful plantar calcaneal spurs, and to verify possible prognostic factors. In this retrospective unicenter study, electronic patient files of patients with painful plantar calcaneal spurs treated with low-dose radiotherapy between July 2009 and February 2020 were reviewed. The low-dose radiotherapy consisted of atotal dose of 3.0 Gy given with afraction dose of 0.5 Gy three times aweek. The pain reduction was estimated using apatient questionnaire with avisual analogue scale. Kaplan-Meier statistics and Cox regression analysis were used for the statistical analysis. Altogether, 864 heels of 666patients were reviewed. The probability of an insufficient pain control 10years after low-dose radiotherapy was 45.9% (95% confidence interval 39.4-52.4%) in the subset of patients with aminimum follow-up of 3months (582 heels of 467patients). Patients with an unsatisfactory pain reduction 3months after low-dose radiotherapy were offered are-irradiation. Forty percent of the patients who received are-irradiation developed good pain reduction. Occurrence of an initial aggravation of pain during or within 3months after low-dose radiotherapy (p = 0.005), and treatment of bilateral painful plantar calcaneal spurs (p = 0.008) were identified as significant unfavorable prognostic factors on univariate analysis. On multivariate analysis, the initial aggravation of pain remained as independent significant prognostic factor (p = 0.01). No clear radiation toxicity was observed. Low-dose radiotherapy is asafe and effective treatment option for patients with painful plantar calcaneal spurs. An initial aggravation of pain during or within 3months after radiotherapy was identified as unfavorable prognostic factor for the treatment outcome. Re-irradiation of patients with an unsatisfactory pain reduction after low-dose radiotherapy is effective and should be offered to patients.