Randomized multicenter follow-up trial on the effect of radiotherapy on painful heel spur (plantar fasciitis) comparing two fractionation schedules with uniform total dose: first results after three months' follow-up.

BACKGROUND: Our first trial on radiotherapy for painful heel spur published in 2012 comparing the analgesic effect of a standard dose (6 × 1.0 Gy within three weeks) to that of a very low one (6 × 0.1 Gy within three weeks) resulted in a highly significant superiority of the standard dose arm. In the meantime, experimental data have shown that lower single doses in the range of 0.5 - 0.7 Gy might be even more effective than the current standard dose of 1.0 Gy. Therefore, we conducted a second trial comparing the analgesic effect of standard single doses of 1.0 Gy to that of low single doses of 0.5 Gy using uniform total doses of 6 Gy.

PATIENTS AND METHODS: One hundred twenty-seven patients were randomized to receive radiation therapy either with a total dose of 6.0 Gy applied in 6 fractions of 1.0 Gy twice weekly (standard dose) or with the same total dose applied in 12 fractions of 0.5 Gy three times weekly (experimental dose). In all patients lateral opposing 6MV photon beams were used. The results were measured using Visual analogue scale (VAS), Calcaneodynia score (CS) and SF-12 health survey. The first phase of this trial ended after a three months' follow-up; it will be continued up to 48 weeks.

RESULTS: Nine patients had to be excluded after randomization either due to the withdrawal of informed consent to radiotherapy by the patients or radiotherapy with an incorrect dosage. The groups were comparable concerning biographical and disease data. The mean calcaneodynia score (CS) was higher in the experimental group (p = 0.002). After three months' follow-up, we saw a very favorable pain relief in both arms (decline of VAS score: standard arm 42 points, experimental arm 44 points (n.s.), but we did not notice any statistically significant difference between the arms neither concerning the pain parameters nor the quality of life parameters. No relevant acute side effects were recorded.

CONCLUSIONS: Favorable laboratory results could not be translated into an enhanced pain relief in our patients. This trial was terminated after the interim analysis (127 patients randomized). Further trials will be necessary to explore the best fractionation schedule. This trial has been approved by the expert panel of the DEGRO as well as by the Ethics committee of the Saarland Physicians' chamber.

TRIAL REGISTRATION: Current trial registration at German Clinical Trials Register with the number DRKS00004458.