Randomized Multicenter Trial on the Effect of Radiotherapy on Plantar Fasciitis (Painful Heel Spur) using Very Low Doses: Mature Results after 12 Months' Follow-up

Due to the lack of literature data with high level of evidence concerning the effect of radiotherapy on painful heel spur, the GCGBD initiated a randomized trial comparing the analgesic effect of a standard dose to a very low one (replacing the placebo arm). Patients with the clinical and radiological diagnosis of painful heel spur were randomized to receive radiotherapy either with a total dose of 6.0 Gy applied in 6 fractions of 1.0 Gy twice a week (standard arm) or with a total dose of 0.6 Gy applied in 6 fractions of 0.1 Gy twice a week (experimental arm). In all patients, lateral opposing 4 – 6 MV beams of linear accelerator were used. The results were measured using the VAS scale (visual analogue scale), the Calcaneodynia-score published by Rowe (measuring pain intensity, use of tools, limitations during work, and daily life activities and problems with gait), and the SF12 health survey as an instrument for assessment of quality of life. The randomized phase of the study was terminated after 3 months' time; however, the follow-up was continued up to 1 year. Patients with insufficient pain relief after 3 months' follow-up were offered a second radiotherapy series with the conventional dosage at any time afterward. After obtaining approval of the local ethics committee and the patients' informed consent, 66 patients have been included in this trial. Four of them had to be excluded later due to withdrawal of informed consent or screening failures. After 3 months' follow-up, the results concerning pain relief and general health status were highly significantly superior compared to those in the experimental arm (VAS-scale: p = 0.001; Calcaneodynia-score: p = 0.027, SF12: p = 0.045). The accrual of patients was stopped at this point. Further evaluation after 12 month follow-up, showed the following results: 1. Highly significantly fewer patients have been re-irradiated in the standard arm compared to the experimental one (p < 0.001). 2. The results of patients randomized into the experimental arm and having been re-irradiated were identical to those of patients in the conventional arm not having been re-irradiated (re-irradiation as a salvage-therapy for the inferior lower dose). 3. Patients experiencing a favorable result after 3 months will show this even after 12 months, the results can be further improved between 3 and 12 months. This study confirms the beneficial effect of radiotherapy with conventional doses on painful heel spur even for a longer time period up to 1 year. Further trials will be performed testing radiotherapy for other benign indications.