A 15 Year Single Centre Audit of the Outcome of Fractionated Superficial X-Ray Radiotherapy Treatment of Recurrent Keloid Tumours
Henry Weatherburn' PhD and John Glees' MD, FRCR, DMRT
Background
For patients who have experienced a keloid recurrence at a site previously treated by surgery and radiotherapy, the efficacy of a further course of radiotherapy for treatment of this recurrence has not been previously reported as a distinct study outcome. This study reports such results.
The results of two series of long-term audits of recurrence rates of keloid tumours, following surgical excision of the keloid and administration of a single (10Gy) dose of superficial X-ray radiotherapy (SXRT) within 24 hours, have previously been reported in 2003 (ref. 1) & 2022 (ref. 2). The study period for the second series of patient treatments has now been extended to January 2025 and, during this entire second series, keloid recurrences were re-treated with fractionated SXRT. The outcome of this re-treatment is now reported.
Methods
Outcomes of patient treatment of keloid tumours between 2010 and 2020, by surgical excision then SXRT within 24 hours, have previously been reported (refs. 2 & 3). This recurrence study has now been extended to January 2025 and recurrence results over a 15-year period derived (see Table 1).
For this treatment regime of 10Gy in one fraction (1#), the Biological Effective Dose (BED), using $\alpha/\beta = 3$ for skin, is 43.3 Gy.
Following a patient reporting a keloid recurrence, re-treatment was undertaken with fractionated SXRT only and using the following protocol: 4Gy administered in 4# at 3-monthly intervals to a maximum dose of 16Gy over 12 months. Treatment was discontinued after 4Gy, 8Gy, or 12Gy if, at review, a successful outcome had been achieved at this dose.
Here the $BED_{3}$ is:
9.3 Gy for 1#
12.6 Gy for 2# (assuming moderate tissue repair)
13.7 Gy for 3#
14.1 Gy for the full 4# course delivered over a 12-month period.
Recurrences were usually small and the results of employing this radiotherapy re-treatment regime for a patient recurrence are summarised below (see Table 2).
Results
Table 1: Keloid Recurrence Rate Post Surgery and SXRT (2010–2025)
| 1. Centre / Period | 2. Dose (Gy) | 3. SXRT Treatment | 4. Patients: Number & Gender | 5. Number of Keloids | 6. Outcome at 4–6 Week Post-Treatment Review | 7. % Relapse Rate After 1 Year | 8. % Relapse Rate After 5 Years |
| Cancer Centre London 2010 – 2025 (January) | $10Gy$ in $1$ fraction ($1\#$) | $60kV$, $100kV$, or $160kV$ X-ray beam | $87$ patients $66\%$ (F) $34\%$ (M) | $158$ keloids | $100\%$ ($158$ keloids) Free from recurrence | $6.8\%$ (for $148^*$ keloids) | $14.7\%$ (for $102^+$ keloids) |
* 10 keloids treated within previous year; *56 keloids treated within previous 5 years
For entire patient cohort (158 keloids): 23 (14.6%)relapsed during the 15 year period
Notes:
1.Minimal skin reaction - reddening /itching and/or pigmentation change for 6 -12 months
2. No cancers recorded
3. Time Period before Relapse: 3.5 months to 10 years
4. Mean Follow-Up Period:7years months (Minimum: 1 month; Maximum: 15 years)
Table 2 - Outcome of Keloid Recurrence Re-Treatments by Fractionated SXRT
(2010-2025)
| 1. Centre | 2. Dose (Gy) | 3. SXRT Treatment | 4. Patients: Number & Gender | 5. Number of Keloids | 6. Outcome at Quarterly Review (Before Next Planned Fraction) | 7. % Relapse* Rate After 1 Year | 8. % Relapse* Rate After 5 Years |
| Cancer Centre London | $4Gy$ at 3-monthly intervals: Maximum dose $16Gy$ (i.e., $4Gy/4\#$) over 12 months | $60kV$, $100kV$, or $160kV$ X-ray beam | $14$ patients
$50\%$ (F)
$50\%$ (M) | $23$ keloids | Treatment discontinued after $2\#$ or $3\#$ in ~50% of patients: further treatment not required. | None; but for $16Gy$ ($4\#/1yr$) patient treatments: response ongoing & outcome yet TBC. | None requiring further re-treatment: patients satisfied with outcome. |
Hallmarks and Notes
Hallmarks of recurrence: Keloid regrowth, itching; red, shiny skin: not present.
Patient Satisfaction: Patients satisfied with treatment outcome, though a minority had residual skin thickening.
Notes:
Minimal skin reaction: Reddening, itching, and/or pigmentation change observed for 6–12 months.
Safety: No cancers recorded.
Mean Follow-Up Period: 6 years 8 months (Minimum: 1 month; Maximum: 13 years 4 months).
Conclusions:
Surgical excision of keloid tumours followed by superficial radiotherapy given within 24 hours in a single dose of 10Gy has proven to be highly effective with minimal side effects and a low 5-year recurrence rate of 14.8%.
In the event of a recurrence, the radiotherapy treatment can be safely repeated in smaller (4Gy) fractions at three monthly intervals, up to a maximum of 16Gy over a year if necessary. When keloid tumours were re-treated, an audit of the outcome of this treatment regime found no recurrences at 5 years though, in a minority of patients, there was some skin thickening.
While the patient numbers in this audit are small and its statistics have low power, they demonstrate that successful retreatment of keloids tumours with radiotherapy alone is possible, with minimal side effects.
It can therefore be proposed that, when considering re-treatment of keloid recurrences by radiotherapy, other centres consider following this treatment regime, then audit outcome data to facilitate comparison and collation of results. A similar approach could also be employed more generally to permit a comparison of outcomes of treatment when other treatment methods, e.g. steroid tape, cryotherapy, laser, etc., are used.
References:
Ragoowansi, R, Cornes, P, Moss A & Glees J, Treatment of Keloids by Surgical Excision and Immediate Postoperative Single-Fraction Radiotherapy. Plastic and Reconstructive Surgery, May 2003, 111(6), 1853-1859
Glees, J and Weatherburn, H Recurrence of Keloid Tumours Following Surgical Excision and Single Dose of Superficial Radiotherapy Given Within 24 Hours. Long Term Follow Up (Personal Series), 4th International Keloid Symposium, 2022
Glees, J and Weatherburn, H Treatment of Keloid Tumours: 40 Years of Experience Using a Single 10 Gy Fraction of Superficial X-Ray Therapy (SXRT) Given within 24 Hours. Plastic and Reconstructive Surgery, in press, 2025.