STUDY PROTOCOLOpen Access
Intralesional cryotherapy versus excision and
corticosteroids or brachytherapy for keloid
treatment: study protocol for a randomised
Eveline Bijlard1*, Reinier Timman2, Gerda M Verduijn3, Frank B Niessen4, Johan W van Neck1,
Jan J V Busschbach2and Marc A M Mureau1
Background: Keloids are a burden for patients due to physical, aesthetic and social complaints and treatment
remains a challenge because of therapy resistance and high recurrence rates. The main goal of treatment is
to improve the quality of life (QoL); this implies that, apart from surgical outcomes, patient-reported outcome
measures (PROMs) need to be taken into account. Decision making in keloid treatment is difficult due to heterogeneity
of the condition and the lack of comparative studies.
Methods/Design: This is a multicentre, randomised controlled open trial that compares 1) intralesional cryotherapy
versus excision and corticosteroids for primary keloids, and 2) intralesional cryotherapy versus excision and brachytherapy
for therapy-resistant keloids. The primary outcome is the Patient and Observer Scar Assessment Scale (POSAS), a 12-item
scale (with score 12 indicating the best and 120 indicating the worst scar imaginable). A difference of six points on the
total score is considered to be of clinical importance. Secondary outcomes are recurrence rates, volume reduction,
Skindex-29 scores, SF-36 scores and complication rates. Primary and secondary outcome measurements are taken at
baseline, and at 2, 12, 26 and 52 weeks postoperatively. For analysis, a linear mixed model is used. A total of 176 patients
will be included over a period of 2.5 years. The protocol is approved by the Medical Ethics Committee of the Erasmus
University Medical Centre Rotterdam and follows good clinical practice guidelines.
Discussion: The outcomes of this study will improve evidence-based decision making for the treatment of keloids, as
well as patient education.
Trial registration: Dutch Trial Register NTR4151.
Keywords: Keloid, Quality of life, RCT, Brachytherapy, Corticosteroids, Cryotherapy, POSAS, Skindex-29, SF36
Keloids are pathologic scars that grow beyond wound bor-
ders and act as a benign tumour. The physical, aesthetic
and psychological complaints that they cause are of great
After injury, the skin heals by forming a scar. Dysregula-
tion of signalling molecules in the complex healing process
can result in keloid formation, with several times more col-
lagen synthesis than for normal skin and normotrophic
scars, and a higher ratio of type 1 to type 3 collagen [3-7].
The aetiology of keloids remains unknown. Although it is
suggested that a relation exists with wound tension, sex
hormones, sebaceous gland activity, melanocyte concentra-
tion and overlying keratinocytes, as well as with genetic
predisposition, no single theory has proven of value in all
aspects of keloids [8-12]. The highest incidence is seen in
patients with a dark skin tone, whereas Mediterraneans,
South Americans, and Asians are slightly less affected, and
Caucasians are the least affected (<1%) [1,8,13]. It was
* Correspondence: firstname.lastname@example.org
1Department of Plastic Reconstructive and Hand Surgery ErasmusMC,
Erasmus University Medical Centre Rotterdam Room EE1591 Dr,
Molewaterplein, 50 3015 GE, Rotterdam, Netherlands
Full list of author information is available at the end of the article
© 2013 Bijlard et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly cited.
Bijlard et al. Trials 2013, 14:439
shown that scars give acceptability problems (91%) and in-
fluence social functioning (82%) in a mixed group of scar
types that were mainly on visible body sites. At least as
much problems can be expected for patients with keloids,
as keloids are often visible on earlobes or so large that they
are visible through clothing. Besides this major psycho-
social burden, keloids give rise to pain and pruritus in 80%
of keloid patients [1,2].
Treatment of keloids is challenging because of therapy
resistance and high recurrence rates, resulting in the
search for more treatment options for keloids. Over de-
cades, systematic reviews included zero to only three
randomised controlled trials per treatment option, with
a lot of heterogeneity between the studies [1,14,15]. In
the absence of sufficient numbers and methodologically
sound randomised trials, no consensus for a treatment
of first choice has been reached.
In our clinical practice a ‘stepped-care approach’ is gene-
rally used; that is, initially, the least invasive and safest
treatments are used, which are changed to more radical
treatments in case of resistance or recurrence.
Because keloid is a benign condition, the main treat-
ment goal should be to relieve the burden, which consists
mainly of pruritus, pain and aesthetic complaints; all these
are subjective symptoms. To objectively measure subject-
ive burden (that is, in a reproducible way) the effects of
the treatment options should be assessed using validated
scar assessment scales and patient-reported outcome mea-
sures (PROMs), in addition to surgical results such as vol-
ume reduction, recurrence and complication rates.
In our centre, the ‘stepped-care approach’ implies that
the first step is generally conservative treatment with
corticosteroid injections. Other conservative methods,
like laser therapy and silicone occlusive dressings, have
not proven to achieve patient satisfaction in keloid treat-
ment as is clear from recent systematic reviews [14-17]. If
keloids are of such a size that conservative treatment may
not be sufficient, the next step is surgical treatment.
Because excision as monotherapy gives a recurrence
rate of ≥70%, an adjuvant treatment should be used. The
most frequently used adjuvants are corticosteroid injec-
tions, pressure therapy and brachytherapy (interstitial
radiotherapy) [14,18]. Another surgical keloid treatment
option that gained popularity some years after several
case series were published, is intralesional cryotherapy
[19-21]. As no trials have compared intralesional cryo-
therapy with established conventional therapies, we
aimed to explore the position of intralesional cryother-
apy in the ‘stepped-care approach’.
Beginning in November 2012, we initiated a randomised
clinical trial in which we compare frequently used keloid
therapies in the Netherlands: excision and intralesional
steroid injections, excision and brachytherapy, and intra-
lesional cryotherapy. Outcomes are surgical results and
PROMs. The results will assist in producing a better
‘evidence-based’ treatment algorithm for keloid patients.
The design is a multicentre, randomised controlled open
trial, which used minimisation to control for skin type,
location and duration of disease. The trial consists of
two parts: one for primary keloids and one for resistant
keloids. Primary keloids are keloids that have not been
surgically treated and, to some extent, have responded
to corticosteroids. Resistant keloids are keloids that re-
curred after excision or those that did not respond to
corticosteroids (progression within six weeks after cor-
For the primary keloids we randomise between either
intralesional cryotherapy or excision and additional cor-
ticosteroids. The resistant keloids are randomised be-
tween either intralesional cryotherapy or excision and
brachytherapy. Follow-up assessments are in weeks 2,
12, 26, and 52 post-treatment. The follow-up period is
based on scar maturation, which lasts about one year,
and the chance of recurrence that usually occurs within
the first year [22,23].
Patients who present with a keloid at an outpatient clinic of
the four participating centres are considered for the study.
A keloid is a clinical diagnosis and is distinguished from
hypertrophic scars by the clinician’s judgement. The judge-
ment between hypertrophic scars and keloid is based on:
the growth history, starting early versus late after trauma,
remaining stable versus still growing; shape, following initial
lesion versus not following the initial lesion; and size, <0.5
cm versus >0.5 cm beyond the original lesion.
At a later stage, we will report how many patients with
keloids were seen and how many were eligible for the
study. Inclusion criteria are:
1. Keloid with a surgical indication.
2. One to three keloids that can be treated in one
3. Minimal size of 1×1 cm.
4. Suitable for excision and primary closure.
5. Patient aged between 18 and 75 years.
6. Fully mentally competent.
7. Sufficient knowledge of the Dutch or English language.
Exclusion criteria are:
1. Hypertrophic scars.
2. Scars after burn wounds.
Bijlard et al. Trials 2013, 14:439
Page 2 of 7
3. Keloids less than one year old.
5. Use of systemic chemotherapeutics or chronic use of
systemic corticosteroids or immunosuppressive
6. Hypersensitivity for local anaesthetics, adrenaline, or
triamcinolone (primary keloids).
7. Patients not sufficiently fit for brachytherapy
8. Severe comorbidity with life expectancy under one
At the first outpatient visit, eligible patients are informed
about the study by a member of the research staff and
written information is provided. After a consideration
period of at least two weeks, the patient is contacted and
registered in the study database when the patient wants
to participate. Before treatment, a witnessed, written in-
formed consent is obtained from all participants, follow-
ing the guidelines of the local ethical committee.
Randomisation (treatment allocation)
Previous studies on keloid treatment showed that spe-
cific characteristics are predictors of recurrence. There-
fore, we want to assure homogeneity between treatment
groups regarding these characteristics, such as duration
of the keloid existence (dichotomous; <5 years or ≥5
years) and location of the keloid (categorical; sternal re-
gion, auricular region and other). In addition, we try to
match for skin type because of the strong association
with the development of keloids, but the doubtful rela-
tion with recurrence rate (categorical; Fitzpatrick type 1
and 2, type 3 and 4, type 5 and 6). Because of the many
different strata that would be formed and considering the
total number of patients to be included, we choose not to
use permuted blocks but will use the more sophisticated
technique of minimisation. We will minimise on the three
factors previously mentioned. The allocation of a new
subject is determined by the allocation of the subjects
already enrolled. We apply a 20% random chance factor
to keep allocation predictability at a minimum. The
software used is the open source program MinimPy
When a patient agrees to participate in the study they ir-
revocably receive a unique identification number, which
cannot be changed or removed from the database. After
completion of baseline measurements, treatment alloca-
tion is conducted through a central computerized alloca-
tion using the locked database for all participating centres.
Then the physician and the patient are informed of the
assigned condition and the treatment is planned. In this
way, allocation concealment is guaranteed.
Excision with additional corticosteroid injections
Extralesional excision is performed with minimal mar-
gins, and absorbable monofilament sutures or perman-
(Monocryl™, Ethilon™, Ethicon Inc, Somerville, NJ, USA).
Surgery is performed by either surgical residents who
have three years minimum experience, or by plastic sur-
geons. This standardised surgical procedure is not de-
manding, and we expect no learning curve. Many
different surgeons (>20) reflect usual clinical practice in
keloid treatment. After 2 weeks, an injection of triamcin-
olone acetonide 40 mg/ml is given in the newly formed
scar. The injections can be repeated at 8 and 12 weeks
are used forclosure
Excision with additional brachytherapy
Extralesional excision is performed with minimal margins,
and absorbable monofilament sutures or permanent
monofilament sutures are used for closure (Monocryl™,
Ethilon™, Ethicon Inc, Somerville, NJ, USA). During the
procedure, brachytherapy catheters are placed direct
subcutaneously in order to cover the affected area.
Next, a target dose of 600 to 900 cGy is given followed
by one or two doses on the day of operation or the day
after. After completion of brachytherapy, the catheter
is removed. .
The Cryoshape needle (Etgar Group International, Kfar
Saba, Israel) is positioned in the centre of the keloid to
guarantee total coverage of the keloid when it is visually
frozen. If necessary the Cryoshape needle is repositioned
to achieve this. Our procedure differs slightly from Har-
Shai et al. as we administer lidocaine with epinephrine
around the keloid instead of intra- or translesional infil-
tration , because in our experience injecting through
the keloid can be difficult and unnecessary painful for
the patient. The cryotherapy can be repeated after three
months if the desired effect has not been achieved.
During the study follow-up patients are not allowed to
use additional keloid treatments. If treatment was not ef-
fective other treatments will be performed after at least
26 weeks follow-up. Follow-up measurements will con-
tinue as planned and patients will receive a request for
an additional follow-up measurement 52 weeks after the
Neither physicians nor patients are blinded for treat-
ment. They cannot be blinded due to surgery under
local anaesthesia and differences in postoperative self-
care instructions. Furthermore, during the follow-up
assessments, a physician or layperson would immediately
Bijlard et al. Trials 2013, 14:439
Page 3 of 7
recognize the treatment type by the resulting wound
Treatments applied in the current study are conventional
rather than experimental. The hospital’s local safety pro-
cedures are followed. Possible side-effects are treated
according to current best practice. No serious adverse
events are expected; however, these will be reported to
the Medical Ethics Committee supervising this study
and registered with EudraVigilance within two weeks
after the investigator is notified of such an event.
The protocol is approved by the Medical Ethics Com-
mittee of the Erasmus University Medical Centre Rot-
terdam and follows good clinical practice guidelines and
current Dutch legislation.
Our primary outcome measure is the Patient and Obser-
ver Scar Assessment Scale (POSAS), a 6-item patient
questionnaire and a 6-item observer questionnaire. The
patient and at least two observers (clinician and investi-
gator) will independently assess the scar. The scores of
the patient will range from 6 for the best imaginable scar
to 60 for the worst scar imaginable, which is a PROM,
the average of the observers scores will also range from
6 to 60. The score of the patient and observers will be
added to form the total score that is our primary out-
come, but the scores will also be analysed separately. A
difference of six points on the total score is considered
to be of clinical importance. The POSAS is a sensitive
instrument that includes both physician and patient opin-
ions of the scar, it has been previously validated, and per-
forms well in a population of mostly dark-skinned keloid
When one or two of the 12 POSAS items are missing at
baseline we imputed the mean of the other scores of the
same assessor. When a follow-up item was missing we im-
puted the last value carried forward. In cases where an
item of the second observer was missing, we imputed the
score of the first observer on the same item.
Secondary outcomes are keloid volume measured using
a plaster mold, made before treatment, after the skin had
completely healed at 12, 26 and 52 weeks. Time to recur-
rence is determined; the physician assesses recurrence at
each follow-up visit; and, in case of recurrence, the patient
is asked how many weeks after treatment the keloid re-
curred. As well as the diagnosis of keloid disease the diag-
nosis of keloid recurrence is a clinical diagnosis based on
new growing scar tissue with features of keloid disease as
described earlier. Photographs are taken at all visits, which
will be used for additional (partial) observer scores on the
POSAS and recurrence assessments. The additional ob-
servers will reduce bias in these outcomes. For assessing
quality of life (QoL) we use a disease-specific and a gen-
eral instrument: the Skindex-29 and the Short Form/
RAND-36 (SF-36), respectively. The Skindex-29 was ori-
ginally developed for psoriasis patients. It consist of 29
questions concerning symptoms, emotions and function-
ing and is, therefore, also suitable for other skin condi-
tions. Questions are rated on a 5-point Likert scale. Scores
range from 0 to 100, with 0 indicating no compromise on
quality of life. A score ≥40 indicates a significant negative
influence of the skin condition on QoL [30,31]. World-
wide, the SF-36 is the most frequently used general QoL
questionnaire. It consists of 36 questions (scored on a
Likert scale) addressing eight dimensions (vitality, physical
functioning, bodily pain, general health perceptions, phys-
ical role functioning, emotional role functioning, social
role functioning, mental health). The dimension scores
are transformed to a 0 to 100 score, with a higher score
indicating a higher QoL [32,33].
We will also analyse single item scores of our primary
outcome measure POSAS, especially itch and pain from
the patient questionnaire, and items on skin colour, pig-
mentation and vascularisation.
Data are collected at baseline, before randomisation, and
at follow-up assessments 2, 12, 26, and 52 weeks after
treatment. The questionnaires are preferably filled out on-
line, although a paper version is also available. All paper
questionnaires are scanned and stored on a secure disk.
The online questionnaires are saved by the online ques-
tionnaire program, and a backup is made regularly.
Photographs are taken at all visits. Volume of the keloid
is measured at baseline and after the skin has completely
healed at 12, 26, and 52 weeks after treatment.
Baseline demographic and clinical characteristics will be
presented as proportions or means and standard deviations
(SD) where appropriate. Because of the longitudinal data
with multiple influencing factors, a sophisticated model is
necessary. Mixed models (also called multilevel linear re-
gression analysis) is a technique that efficiently uses longi-
tudinal data and can work with patients’ data even though
measures at certain time points may be missing.
The units of analysis are the repeated measurements of
the patient (first level), not the keloid, because we use sev-
eral QoL measures that are not measurable for the unit ke-
loid. The second level will be the individuals participating
in the study. If necessary, a third level of subgroups with
specific characteristics (skin type, duration of keloid disease
and location of the keloid) can be added. If the third level
is shown to improve the fit of the model, it will be incor-
porated in the model. We will use backward elimination
and start with an unstructured covariance structure for
Bijlard et al. Trials 2013, 14:439
Page 4 of 7
intercept and time (slope). Simplifications of the random
part of the model will be tested using the deviance statistic
with restricted maximum likelihood. For the fixed part we
will postulate a saturated model. We take in account time,
logarithm of time and squared time, treatment condition
and its interactions with time. Nonsignificant effects will
be excluded using Wald tests. The fit of the final fixed
model will be compared with the saturated model and will
be checked using ordinary maximum likelihood. When
characteristics like sex, age, skin type, duration of keloid
disease and location of the keloid make a significant contri-
bution to the model, they will be incorporated in the model
[34-37]. Differences between treatment effects will be
expressed in terms of effect sizes, standard errors and P
values. Effect sizes will be calculated by dividing the esti-
mated differences by the estimated standard deviation. An
effect size of 0.20 is considered a small effect, 0.50 a
medium effect and 0.80 as a large effect .All analyses
will be performed on an intention-to-treat basis. IBM SPSS
version 21.0 and SAS version 9.3 will be used to perform
Sample size calculation
There are no meaningful rules of thumb to estimate the
sample size needed for a mixed models analysis, because,
with random and fixed effects estimations, too many fac-
tors of uncertainty are involved. Therefore, a standard
sample size calculation with a correction for the design
effect based on the intercorrelation was used.
These calculations were performed in SPSS version 20.0
using the mixed-model ANOVA procedure as described
by Aberson . Type 1 error (alpha) was set at 0.05, and
power (1-beta) on 0.80.
To estimate the effect size and correlation we analysed
data of a natural cohort collected by one of the authors
(FBN) containing general features of keloid patients and
POSAS values before and after treatment with intralesional
cryotherapy. This natural cohort contains measurements at
baseline, and at 12, 26, and 52 weeks after treatment. It
comprised POSAS observer values from one or two ob-
servers and patient values; however, many patients lacked
values for some time points (56% of follow-up complete).
Only a small amount of items were missing, in total 15/
3378 (0.44%) items of the POSAS data were imputed fol-
lowing the rules described previously.
The assumed medium-sized effect of 0.5, based on a
SD of around 15 (Table 1), corresponds to 7.5 points on
the POSAS scale; this is slightly more than the 6 points
that is regarded as a clinically significant difference. We
assumed a correlation of 0.75 between time points; this
was difficult to verify in the data of the natural cohort
because of many incomplete cases.
The analysis, based on the observed SD and expected
correlation and effect size, resulted in a group size of 33
patients, taking into account a 25% loss to follow-up and
the four treatment groups; this results in a total sample
of 176 subjects.
No interim analysis is planned because we do not expect
any severe side-effects and, by the time a sufficient part of
the participants has finished follow-up, almost all partici-
pants will have had their intervention. No rules related to
stopping/withdrawal from the study have been specified.
The risks of undergoing surgical treatment include com-
plications due to undergoing anaesthesia and surgery;
however, these risks are equivalent to the risks of surgical
treatment without participating in the study. Only patients
not responsive to conservative treatment and who opt for
surgical treatment, despite knowing the risks, are enrolled
in the trial.
Anticipated benefit for the medical world is improved
outcome for future patients. The results will improve de-
cision making, helping evidence-based guidelines to be
developed for keloid treatment. We aim to determine
the place of intralesional cryotherapy in the ‘stepped-
care approach’ (that is, whether it should be used as sec-
ond step, be added as an extra step, or has no place at
all in the treatment of keloids). If cryotherapy is shown
to be effective for resistant keloids, then savings can be
made by avoiding the costly brachytherapy treatment. If
cryotherapy is not effective, the patient will receive ap-
propriate treatment sooner.
We will include patients over a period of 2.5 years and
will follow every patient for one year, resulting in a total
study period of 3.5 years.
We have described a trial protocol; this is becoming stan-
dard practice when conducting clinical trials, although
surgical trials are somewhat behind medical trials. The
importance of publishing an extensive protocol is that it
addresses questions (that may not be answered in the
Methods section due to limited space) that might arise on
how the trial was organised after publication of the results.
Table 1 Descriptive statistics
N Minimum MaximumMeanSD
POSAS baseline73 30 93 60.45 12.276
POSAS 12 wk post op44 188550.65 15.474
POSAS 26 wk post op46 17 83 49.2315.854
POSAS 52 wk post op33 2481 46.1813.959
POSAS overall196 17 9353.32 15.20
POSAS, Patient and Observer Scar Assessment Scale score; post op, postoperative.
Bijlard et al. Trials 2013, 14:439
Page 5 of 7
It also prevents publication bias due to inconclusive or
negative results. This will be the first randomised con-
trolled trial comparing surgical keloid treatments using
We have presented the problems with power analysis
and sample size calculations for a more complex but so-
phisticated statistical model. In this corrected analysis we
did not rely on assumptions only, but used previously col-
lected data to determine the effect size and intercorrel-
ation. The effect size we have chosen is a conservative one
in order to ensure clinical relevance. When the effect size
appears in fact to be smaller, we expect to be underpow-
ered. Due to the quantity of work involved in logistics and
data collection, we made this decision despite the risk of a
At the time of submission of this protocol (August
2013), this study was recruiting patients to participate in
POSAS: Patient and Observer Scar Assessment Scale; PROM: Patient Reported
Outcome Measure; QoL: Quality of life; SD: Standard deviation; SF-36: World
Health Organisation Quality of Life assessment Short Form-36.
The authors declare that they have no competing interests.
EB (coordinating investigator), FBN, JWvN and MAMM designed the study.
MAMM is grant holder. RT, JJVB and GMV contributed to the design in their
specific fields or to the statistical analysis, QoL measurements and protocol,
and conducting brachytherapy. MAMM, FB, GMV and EB contributed to
implementing the protocols and data collection. All authors have read and
approved the final manuscript.
The study will be performed in university medical centres, which are ideally
suited because of their experience with all the treatments to be used.
MAMM and FBN are plastic surgeons with extensive experience in
reconstructive surgery, especially scar treatment. GMV is a radiation
oncologist with special focus on keloid treatment. JJVB professor and RT are
research staff of the Department of Psychiatry, Section Medical Psychology
and Psychotherapy, and JWvN is head of the research section of the
Department. of Plastic Reconstructive and Hand Surgery and all three are
experienced in methodology and other aspects of conducting a clinical trial.
This project is funded by the NutsOhra Foundation (Project number 1104–062),
an independent foundation aiming to improve health care. The authors thank
Bloomedical for training and assistance with the introduction of the
cryotherapy treatment in the Erasmus University Medical Centre. We paid
83% of advised retail prices for all products ordered from Bloomedical, this
discount was offered because of the large order size. We also thank the
National Institute of Health Sciences (NIHES), Rotterdam for tutoring during
the development of the manuscript. The views and opinions expressed
therein are those of the authors and are not influenced by the NutsOhra
Foundation, Bloomedical or NIHES.
1Department of Plastic Reconstructive and Hand Surgery ErasmusMC,
Erasmus University Medical Centre Rotterdam Room EE1591 Dr,
Molewaterplein, 50 3015 GE, Rotterdam, Netherlands.2Department of
Psychiatry, Section Medical Psychology and Psychotherapy ErasmusMC,
Erasmus University Medical Centre Rotterdam’s, Gravendijkwal, 230 3015 CE,
Rotterdam, Netherlands.3Department of Radiation Oncology, ErasmusMC,
Erasmus University Medical Centre Rotterdam, Groene Hilledijk, 301 3075 EA,
Rotterdam, Netherlands.4Department of Plastic Reconstructive and Hand
Surgery, VU Medical Center, University Medical Centre, Boelelaan 1117, 1081
HV, Amsterdam, Netherlands.
Received: 26 August 2013 Accepted: 9 December 2013
Published: 19 December 2013
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Cite this article as: Bijlard et al.: Intralesional cryotherapy versus excision
and corticosteroids or brachytherapy for keloid treatment: study
protocol for a randomised controlled trial. Trials 2013 14:439.
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