Intralesional cryosurgery of keloids: required treatment hold time
Authors: C. C. Zouboulis, T. Wild, V. A. Zouboulis, Y. Har‐Shai
Journal: British Journal of Dermatology (2020)

dear editor, Cryosurgery, a safe physical regimen with only a few adverse effects and contraindications, provides satisfactory results in the generally frustrating treatment of keloids.1 Contact cryosurgery has mostly been applied,2 whereas intralesional cryosurgery3 is a relatively new, safe, therapeutic modality with a still limited level of evidence (15 evidence-relevant studies from 105 publications).4 The fact that intralesional cryosurgery induces only low temperatures and achieves a long freezing time in the deep scar core, causing minimal damage and hypopigmentation to the superficial skin, is of paramount importance in keloid treatment.5, 6 In addition, marked efficacy of a single intralesional cryosurgery session has been recorded even in voluminous keloids, which is an additional major advantage compared with the repeated sessions required in classical contact cryosurgery.4, 5 In order to assess the expected reduction of keloid volume after a single session and the required optimum keloid treatment hold time (duration) with intralesional cryosurgery, a monocentric retrospective study was conducted using a review of hospital records, which randomly included a maximum of two keloids per patient. A total of 145 keloids from 76 patients (1 : 1 male/female ratio, age 28·2 ± 9·2 years) were evaluated, with a median keloid volume of 7·55 cm3 [absolute range 0·5–930 cm3, interquartile range (IQR) 3·0–16·8 cm3], mostly localized on the area of the sternum (n = 57, IQR 3·0–14·7 cm3), the ears (n = 33, IQR 3·5–13·9 cm3) and the shoulders (n = 30, IQR 3·5–13·9 cm3). Moreover, 14 keloids were localized on the face/neck area, two on the upper back and nine keloids were located on the lower arms, pubic area and buttocks. Results were analysed using Microsoft Excel (Microsoft Corporation, Redmond, WA, USA). There was an overall volume reduction of 52·2 ± 28·1% 6 months after a single treatment (total freezing of the lesion including a 5-mm margin of healthy-appearing perilesional tissue).3, 7 Sternum keloid volume was reduced by 41·5 ± 26·8%, ear keloid volume was reduced by 59·1 ± 28·7% and shoulder keloid volume was reduced by 59·1 ± 28·7% (not significant). Scar volume was the parameter that had a linear association with the treatment hold-time log of the entire group of lesions (Figure 1a) and with the treatment hold-time log of lesions grouped according to their localization (Figure 1b). The Pearson correlation coefficient r2 was substantial for the shoulder keloids (r2 = 0·98) and moderate for the ear (r2 = 0·65) and sternum (r2 = 0·41) keloids according to the scale of Chin (0·19–0·32 poor reliability, 0·33–0·66 moderate, 0·67–1·00 substantial). The current study corroborates the results of our own previous series showing an average of 51% scar volume reduction achieved following a single intralesional cryosurgery treatment or multiple contact cryosurgical sessions.1 Under intralesional cryosurgery, even higher improvement of scar volume has been reported by other groups.4, 8 As in previous studies, ear keloids (previous studies 67%) and shoulder keloids (60%) exhibited higher than average response rates after intralesional treatment.7 No response has been documented in 7% of the patients who underwent intralesional cryosurgery and 10% of the patients who were treated with the contact method.2, 5 Significant alleviation of objective (hardness and redness) and subjective clinical symptoms (pain/tenderness and itchiness/discomfort) were reported. Keloids responding to intralesional cryosurgery were much larger than those treated with contact cryosurgery.4 During the follow-up period no keloid infection and only minimal hypopigmentation were registered under intralesional cryosurgery.3, 4 The histomorphometric analysis demonstrated rejuvenation of the treated scars.5 A pain control protocol, which involved oral pain-relief tablets and translesional local anaesthesia, revealed a reduction of pain severity to tolerable levels during the cryosurgery treatment (visual analogue scale ≤ 3).3 Therefore, while small keloids may improve under classical cryosurgery,2 intralesional cryosurgery is an evidence-based effective and safe therapeutic technique for voluminous keloids.1, 3, 4 On the other hand, while contact cryosurgery lasts 30 s per lesion and session,1, 2 the fact that optimum performance of intralesional cryosurgery requires freezing of the entire lesion and a 5-mm healthy-appearing skin margin did not allow for exact timing of the surgical procedure until now.7, 8 Our data provide exact algorithms for calculating the required time, which is dependent on the volume and the localization of the lesions. Open access funding enabled and organized by Projekt DEAL. Christos C. Zouboulis: Conceptualization (lead); Data curation (lead); Formal analysis (lead); Investigation (lead); Methodology (lead); Project administration (lead); Resources (lead); Visualization (lead); Writing-original draft (lead); Writing-review & editing (lead). Thomas Wild: Data curation (equal); Writing-original draft (equal); Writing-review & editing (equal). Viktor A. Zouboulis: Formal analysis (equal); Software (equal); Writing-original draft (equal); Writing-review & editing (equal). Yaron Har-Shai: Writing-review & editing (equal).