SYSTEMATIC REVIEW ARTICLE
Nagoya J. Med. Sci. 83. 673–681, 2021
doi:10.18999/nagjms.83.4.673

Efficacy and safety of cyclooxygenase 2 inhibitors fordesmoid tumor management: a systematic review
Makoto Emori1, Yoshihiro Matsumoto2, Yasutaka Murahashi1,
Masahiro Yoshida3 and Yoshihiro Nishida4
1
Department of Orthopedic Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan
Department of Orthopedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka,Japan
3
Department of Hepato-Biliary-Pancreatic and GI surgery, International University of Health and Welfare
School of Medicine, Ichikawa, Japan
4
Department of Rehabilitation Medicine, Nagoya University Hospital, Nagoya, Japan
2

ABSTRACTThe efficacy and safety of cyclooxygenase 2 (COX2) inhibitors for the treatment of desmoid-type
fibromatosis (DF) are unclear. Therefore, we systematically reviewed related literature to assess the efficacy and safety of COX2 inhibitors for DF treatment. We searched pertinent literature between January
1999 and August 2017 to identify relevant studies using the keywords “Fibromatosis, aggressive” and“Cyclooxygenase inhibitors.” Thereafter, we screened and determined the quality of the studies using the
Grading of Recommendations Assessment, Development, and Evaluation system and extracted the article
data. The critical outcomes selected were the efficacy and adverse effects of COX2 inhibitors. Efficacy
was evaluated in terms of clinical benefit when patients showed complete response, partial response, andstable disease. Thirty-one articles were identified from the database search, and one was identified throughthe reviewers’ manual search. Finally, we retrieved six studies, including three case reports, comprising 89
patients after the first and second screenings. Fifty-three patients were excluded because three studies werereported from the same institution; hence, in total, 36 patients were included. Clinical benefit was notedin 64% of the patients. Three adverse effects were identified from the records of the six extracted studies.
The strategy of watchful waiting using COX2 inhibitors with few side effects is weakly recommended for
DF, especially DF patients with pain.
Keywords: cyclooxygenase 2 inhibitors, desmoid, response rate, adverse effect, systematic review
Abbreviations:
COX: cyclooxygenase
CR: complete response
DF: desmoid-type fibromatosis
NSAIDs: nonsteroidal anti-inflammatory drugs
PR: partial response
SD: stable disease
This is an Open Access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
License. To view the details of this license, please visit (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Received: January 5, 2021; accepted: February 10, 2021
Corresponding Author: Makoto Emori, MD, PhD
Department of Orthopedic Surgery, Sapporo Medical University School of Medicine, South 1,West 17,
Chuo-ku, Sapporo 060-8543, Japan
Tel: +81-11-611-2111 (ext. 33330), Fax: +81-11-641-6026, Email: memori@sapmed.ac.jp
673

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INTRODUCTION
Desmoid-type fibromatosis (DF) is a rare monoclonal, fibroblastic proliferation marked by
infiltrative growth and an inability to metastasize. Historically, the management of DF involved
surgical resection with negative margins as the standard treatment. However, occasionally, complete surgical resection can be difficult to achieve. Furthermore, the rate of local recurrence ishigh even after wide resection and is accompanied by the risk of chronic pain, loss of function,and impaired quality of life because DF infiltrates the surrounding structures and spreads alongplanes and muscle.1
Given the unpredictable nature of the disease, including the possibility of spontaneous
regression, increasing attention has been directed toward initial nonoperative management. 2,3
Nonoperative treatment includes watchful waiting using nonsteroidal anti-inflammatory drugs(NSAIDs) with or without hormonal manipulation, chemotherapy, or radiation therapy. Aggressive
chemotherapy should be avoided because it is associated with significant morbidities. NSAIDs
are a relatively safe treatment for DF. Pharmacological blockade of cyclooxygenase 2 (COX2),
which was reported to decrease cell proliferation in animal models, may contribute to therapeutic
effects in DF.4 However, the antitumor activity of COX2 inhibitors for clinical use in humans
is not well understood. Hence, the objective of this study was to systematically review thepertinent available literature to assess the efficacy and safety of COX2 inhibitors for treating
patients with DF.

METHODSWe established a guideline committee for extra-abdominal DF to develop optimal clinicalguidelines for DF management under the direction of the Ministry of Health, Labour and Welfareof Japan with the cooperation of the Japan Orthopedic Association (JOA) and the Bone andSoft Tissue Oncology Committee of the JOA.5 The committee outlined the initial project scope;
key principles; and relevant patient/population, intervention, comparison, and outcome (PICO)
questions. The Grading of Recommendations Assessment, Development and Evaluation (GRADE)
system6 was employed to combine the results of the systematic review with expert opinion toaddress the following clinical question for extra-abdominal DF: “Is nonoperative treatment using
COX2 inhibitors effective for patients with extra-abdominal DF?”
Conflicts of interest and selection of systematic review members
No specific industry played any roles in this consensus meeting, including the systematic
review committee. Members of the systematic review committee were invited to join by thechair (Y.N.) and the clinical practice guidelines development committee.
Search strategy
An expert librarian (N.Y. mentioned in the acknowledgments) searched PubMed/MEDLINE,
the Japan Medical Abstract Society (JMAS; Ichushi in Japanese), the Cochrane library, theGuideline in National Quality Measures Clearinghouse, and the National Institute for Health andCare Excellence databases for potentially relevant literature between January 1999 and August
2017. The following search keywords were used: “Fibromatosis, aggressive” and “Cyclooxygenase
inhibitors“. We screened and determined the quality of the studies using the GRADE system andextracted the data from the articles.7

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Cyclooxygenase 2 inhibitors for desmoid tumor

Study selection
The eligibility of the selected articles was determined in two phases. In the first phase of
study selection, we evaluated the studies for eligibility by screening the titles and abstracts. In
the second phase, we obtained and screened the full text of all papers according to our inclusionand exclusion criteria. This systematic review for the PICO question, “Is nonoperative treatmentusing COX2 inhibitors effective for patients with extra-abdominal DF?,” was composed of (P)participants: patients with extra-abdominal DF; (I) intervention: nonoperative treatment using
COX2 inhibitors; (C) comparison: watchful waiting, and (O) outcomes: the critical outcomesselected were efficacy and adverse events. The articles selected included studies with all typesof study designs: cases reports, case series, case-control studies, and clinical trials. The exclusion
criteria were as follows: (a) non-English and non-Japanese language; (b) animal subjects; (c)review articles or comments; and (d) experimental studies.
Data extraction and quality appraisal
Data were extracted by an experienced investigator belonging to the Japan Medical Library
Association (N.Y.). The data recorded were the first author, publication year, study design, type of
COX2 inhibitor, and efficacy of and adverse effects of COX2 inhibitors. The primary outcome tobe evaluated was the efficacy of COX2 inhibitors in DF patients, which was evaluated according
to Response Evaluation Criteria in Solid Tumors (RECIST). Efficacy was evaluated in terms ofclinical benefit when patients showed complete response (CR), partial response (PR), and stabledisease (SD). The second outcome to be evaluated was adverse effects. The methodologicalquality of the included studies was assessed by two investigators (M.E. and Y.M.) independently
according to the methods proposed by the Minds Tokyo GRADE center.
Rating the quality of evidence
The two reviewers independently rated the quality of the evidence according to the GRADE
approach.8 We used the Cochrane risk of bias tool for the assessment of bias risk.9 The tworeviewers evaluated the extracted individual studies and created ‘an evaluation sheet’ for eachcritical and important outcome, taking into account limitations of the study design, integrated
bias risk, increasing factor and indirectness to PICO, and event number of patients/risk numberof patients. Based on the evaluation sheets of all outcomes, the reviewers created the ‘Body
of Evidence’ for the clinical question in consideration of limitations of the study design, riskof bias, inconsistency, indirectness, imprecision and other factors according to the methods
proposed by Minds Tokyo GRADE center as A (strong), B (moderate), C (weak) and D (veryweak). The reviewers created a ‘Qualitative Systematic Review’ and a ‘Summary of Systematic
Review Report’, which they provided to the clinical guideline committee. A recommendation was
decided in consideration of the balance of relative benefits and harm of the COX2 treatment, thequality of the evidence and patients’ preferences, under GRADE approach. The clinical guideline
committee voted on the recommendation and its strength related to this clinical question. To
decide them, 75% consent was required. If 75% agreement was not obtained in the first vote,the voting members discussed again before re-voting. For the developed recommendation, awritten explanation was given that led to the decision by the guideline member in charge ofthis clinical question.

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Makoto Emori et al

RESULTS
Study selection and study characteristics
In total, 32 articles were identified from the database search and one article was identified
through other sources by the reviewers’ manual search. Of the 33 articles, 11 were excluded as
their title or abstract was not relevant to the outcome of interest for the review. The full textsof the remaining 22 articles were examined as the second screening. In total, 16 articles were
excluded for not meeting the eligibility criteria for evaluation. The most common reason for
exclusion was the combined use of COX2 inhibitors with other drugs (n = 10), comment or
editorial (n = 3), and experimental model (n = 3). Finally, six articles met the eligibility criteria
for evaluation in this systematic review. A detailed flowchart of the selection process is shown in
Figure 1. All studies were single-center, retrospective, and case series. The number of participantsin each study ranged from one to 33; the studies enrolled a total of 89 patients. However, two12,14
studies out of three12-14 were excluded to prevent the inclusion of duplicate cases, because threeresearch papers were published from the same institution. Of the three papers, the study with

Fig. 1

Detailed flowchart of the study selection process

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Cyclooxygenase 2 inhibitors for desmoid tumor

the largest number of cases was selected. Finally, 4 studies and 36 patients were included in thisreview. The characteristics of the selected studies are shown in Table 1. The medication period
ranged from 2 to 113 months. In this systematic review, a comparison with watchful waitingalone was not possible because no comparative study was available.

Table 1 The characteristics of the 4 studies after 1st and 2nd screening
Reference

Study

Patient
numberCOX2
inhibitors

Rate of
Outcome(%)

Response (patient number)

Adverseeffect patientnumberComplete
response

Partialresponse

StablediseaseProgressive
diseaseHamadaet al13case series,
retrospective

33

meloxicam
10mg/day

60

1

7

12

13

0

Yang
et al11case report,
retrospective

1

celecoxib
200mg/day

100

1

0

0

0

0

Tanakaet al15case report,
retrospective

1

etodolac
200mg/day

100

1

0

0

0

1
(hot flushes)

Wang
et al10case report,
retrospective

1

celecoxib
200mg/day

100

1

0

0

0

0

Nishida et al12 and Hamada et al14 were excluded from the review because of the possible overlap with Hamada et al study.13

Efficacy of NSAIDs
Table 1 shows the results of each study and case report with regard to the outcomes ofclinical benefit and adverse events. Three kinds of medication were used: celecoxib (200 mg/day),10,11 meloxicam (10 mg/day),12-14 and etodolac (200 mg/day).15 Of the 36 patients evaluated,
4 showed CR, 7 showed PR, 12 showed SD, and 13 showed progressive disease. Therefore, theclinical benefit was 64%.
Adverse effects of NSAIDs
Among the included studies and case reports (the initial six studies), only one study and acase report provided information regarding adverse effects.8,13 There were only three adverse
effects, gastritis, diarrhea, and hot flushes. Only one adverse effect was described in the fourstudies selected (Table 1).
Body of evidence, Qualitative Systematic Review, and Summary of Systematic Review Report
The reviewers created the “Body of Evidence” of important outcomes (efficacy and adverse
events) for the clinical question and integrated it (Table 2).7 Since all articles were case series
or case reports, the strength of evidence began with C. There were several “Serious” biases inthe selected studies; therefore, we considered that the evidence level should be lowered fromC to D for efficacy. Regarding adverse events, the existence of several biases could lead to avery low rate of incidence. Hence, the strength level was also reduced from C to D for adverse
events. “Qualitative Systematic Review” for clinical question was summarized (Table 3). The
reviewers also created the “Summary of Systematic Review Report” as follows, “there were no
articles comparing the results of clinical benefit between watchful waiting with COX2 inhibitor
administration and without. All articles on clinical benefit in the COX2 inhibitors administration
are retrospective case-accumulation studies, and the target patients are also inconsistent with thefirst and recurrence cases, and the evidence is extremely low.” Clinical benefit was favorable
and adverse effect was very rare with COX-2 inhibitor administration. Therefore, the guideline

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Makoto Emori et alcommittee considered the conservative treatment using COX2 inhibitors was more valuable andpreferable than conservative treatment without COX2 inhibitors. Furthermore, the conservative
treatment using COX2 inhibitors gave little burden to patients with extra-abdominal desmoid
fibromatosis because treatment using COX2 inhibitors is within health care services provided
by health insurance in Japan.
The “Body of Evidence,” “Qualitative Systematic Review,” and “Summary of Systematic
Review Report” created by the reviewers were submitted to the guidelines committee. Basedon these reports, the guideline committee discussed the following points. Clinical benefit wasfavorable and adverse effect was very rare with COX-2 inhibitor administration. The conservative
treatment using COX2 inhibitors was more valuable and preferable than conservative treatment
without COX2 inhibitors in patients with pain. Furthermore, the conservative treatment using
COX2 inhibitors gave little burden to patients with extra-abdominal desmoid fibromatosis because
treatment using COX2 inhibitors is within health care services provided by health insurance inJapan. All together, the guidelines committee in charge of the clinical question proposed thefollowing recommendation: “We weakly recommend nonoperative treatment using COX2 inhibitors in patients with DF.” This recommendation gained a consensus rate of 94% in the entire
guidelines group.

Table 2Study
designStudy quality of evidence according to GRADE guidelines

OutcomesNo.
ofstudies

Risk
of
bias

Efficacy of
COX2inhibitors*(CR+ PR+ SD)

4

Case
Seriousseriesand casereportAdverse events

1

CasereportSerious

Inconsistency Imprecision Indirectness Others

Rate
Level
Significanceof outcome
of
of
a
(%)
evidenceoutcomeb

Not serious

Not serious

Serious

Serious64

D

8

Serious

Serious

Serious

Serious3

D

6*Complete remission + partial response + stable diseaseaA, strong; B, moderate; C, low; D, very lowb
Significance of outcome was determined by guideline committee when setting up PICO by a 1–10 point evaluation. (10:most important)

Table 3

Qualitative systematic review

Clinical question

Is nonoperative treatment using COX2 inhibitors effective for patients with extraabdominal desmoid fibromatosis?

P

Patients with extra-abdominal desmoid fibromatosis

I

Nonoperative treatment using COX2 inhibitors

C

Watchful waiting

Clinical context

Since desmoid fibromatosis shrink spontaneously in some cases, careful follow-up by“wait and see” may be performed. Verify whether COX2 inhibitors are more usefulfor extra-abdominal desmoid fibromatosis than “wait and see” as a drug treatment.

OutcomeResponse rate

Summary of indirectness

All 4 studies do not have a watchful waiting group

Summary of bias risk

All are retrospective studies and have a high risk of bias

Summary of inconsistencies

Subjects include first-onset and recurrent cases, and are inconsistent

Comment

All are retrospective and do not include the watchful waiting group, so the level ofevidence is low.

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Cyclooxygenase 2 inhibitors for desmoid tumor

DISCUSSION
In this systematic review, four studies including case reports were studied to evaluate theefficacy and safety of COX2 inhibitors for DF treatment. The clinical benefit rate of COX2
inhibitors for DF treatment was 64% and the rate of adverse effects was very low (3 cases insix studies, 1 case in 4 studies). Patients with DF could be treated using “watchful waiting” with
COX2 inhibitors because they afford favorable local control and are associated with a low rateof adverse effects. Watchful waiting with COX2 inhibitors allows patients to avoid the significant
morbidity risk associated with surgery or radiation and invasive intervention.
Therapy for DF is aimed at local control and/or reduction of symptoms that bother patients
because DF does not have metastatic potential. Historically, complete surgical resection with wide
margins has been the standard care; however, resection of this type often results in significant
functional impairment. Moreover, the rates of local recurrence after resection, even with wide
surgical margins, are high, ranging from 20 to 60% depending on the series.16-18 While DF has anunpredictable natural history, some cases show rapid growth followed by periods of stabilization;occasionally, spontaneous regression is noted. Spontaneous regression is reported in up to 20%
of DF patients.19 Therefore, watchful waiting is increasingly advocated for DF patients. With
regard to real-world clinical experience, many DF patients have complained of pain, leading
to poor quality of life. Although COX2 inhibitors could control DF based on the results of ananimal study,4 the efficacy of COX2 inhibitors in human DF is controversial because of a lack ofrandomized controlled studies. In this review, the clinical benefit achieved with COX2 inhibitors
was favorable; however, comparison with watchful waiting alone was not possible. Watchful
waiting with COX2 inhibitors could be considered one of the treatment choices because of thefavorable local control and low rate of adverse effects associated with these drugs; moreover,DF patients experience severe pain. Our findings support the current consensus released by theEuropean Organization for Research and Treatment of Cancer (EORTC). The EORTC advocatesthat observation should be the first-line treatment, irrespective of pain or clinical symptoms.2,20
However, pain management is a major issue for patients with DF. The pathogenetic mechanismsof pain in DF are certainly complex and multifactorial. DF-related pain is associated with theoverexpression of COX2.21 Therefore, watchful waiting with COX2 inhibitors may be suitablefor DF patients with pain.
The course of DF is difficult to predict; therefore, it is important to identify the predictors of
DF progression during watchful waiting. Cassidy et al reported that the percentage of baseline
tumor volume showing a hyperintense signal on T2 magnetic resonance imaging is a useful toolfor clinical decision-making for patients with DF considering watchful waiting.22 DF patients witha hyperintense T2 score of ≥90% have a high likelihood of progression. Therefore, for these DF
patients, watchful waiting with or without COX2 inhibitor administration might not be sufficient
as a treatment modality.
There are limitations to the current systematic review that are common to most papers evaluating rare diseases. The evidence from the included studies was of low quality, and there weremany case reports. Moreover, three studies of case series were from the same institution, twoof which should be excluded from this systematic review. In addition, there are some variationsin the medication. Clinical outcomes of watchful waiting with or without COX2 inhibitor shouldbe evaluated in the future.

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Makoto Emori et al

CONCLUSION
The efficacy of COX2 inhibitor treatment was favorable among patients with DF, although
there is no comparative study with no treatment. Further, the incidence rate of adverse eventswas very low. Considering that many DF patients experience pain that cannot be ignored, we
weakly recommend watchful waiting using COX2 inhibitors for DF patients. However, clinicaloutcomes of watchful waiting with or without COX2 inhibitor should be evaluated in the future.

ACKNOWLEDGEMENTS
We thank Japan Medical Library Association and Mr Naohiko Yamaguchi for their support
to literature search.

DISCLOSURE STATEMENT
The authors declare that they have no conflict of interest.

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