Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2023;13(3):e2023152 1 Persistent Chemotherapy-Induced Alopecia Treated With Low Dose Oral Minoxidil: A Multicenter Retrospective Case Series of 15 Patients Matilde Iorizzo1, Anna Waśkiel-Burnat2, Jasmine Anedda3, Bianca Maria Piraccini4, Zoe Apalla5, Lidia Rudnicka2, Michela Starace4 1 Private Dermatology Practice, Bellinzona/Lugano, Switzerland 2 Department of Dermatology, Medical University of Warsaw, Warsaw, Poland 3 Dermatology Clinic, Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy 4 Dermatology Unit - IRCCS Policlinico Sant’Orsola - Department of Specialized, Experimental and Diagnostic Medicine, University of Bologna, Bologna, Italy 5 Second Dermatology Department, Aristotle University of Thessaloniki, Papageorgiou General Hospital, Thessaloniki, Greece Key words: persistent chemotherapy induced alopecia, permanent chemotherapy induced alopecia, cancer survivors, cancer patients, oral minoxidil Citation: Iorizzo M, Waśkiel-Burnat A, Anedda J, et al. Persistent Chemotherapy-Induced Alopecia Treated With Oral Minoxidil: A Multicenter Retrospective Case Series of 15 Patients. Dermatol Pract Concept. 2023;13(3):e2023152. DOI: https://doi.org/10.5826/dpc.1303a152 Accepted: February 3, 2023; Published: July 2023 Copyright: ©2023 Iorizzo et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing interests: None. Authorship: All authors have contributed significantly to this publication. Corresponding author: Michela Starace, Dermatology, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, V. Massarenti 1, 40138, Bologna, Italy. Tel +39051-6364867; Fax +39-0516364867; E-mail: michela.starace2@unibo.it Introduction Persistent chemotherapy-induced alopecia (PCIA) is de- fined as the absence of hair regrowth after more than 6 months of treatment discontinuation [1]. Topical minoxi- dil has been considered as the drug of choice in prevention or treatment of CIA. In a case of PCIA the efficacy of topi- cal minoxidil may be limited [2,3]. Moreover, it may cause scalp irritation with itching, dryness and scaling. The use of low-dose oral minoxidil (LDOM) for the treatment of var- ious forms of hair loss has demonstrated great efficacy [4]. To date, data considering efficacy of LDOM in PCIA are limited [2,5]. Case Presentation A retrospective analysis of case series of 15 patients treated with LDOM for PCIA (Table 1) was performed. All patients with biopsy-proven PCIA with no efficacy from topical minoxidil used for at least one year were included. Patients with diagnosis of other form of hair loss or using other, than oral minoxidil, drug for alopecia were excluded. All patients presented with thinned and sparse hair, with more or less pronounced areas of bare scalp. Trichoscopy showed a reduction of follicular units with an increase in vellus hair formation in the absence of inflammation and scarring. LDOM was used at a daily dose of 1.5 mg in less 2 Research Letter | Dermatol Pract Concept. 2023;13(3):e2023152 severe cases (seven cases with grade 1 alopecia according to CTCAEv5.0) and 2.5 mg in more severe ones (eight cases with grade 2 alopecia). Efficacy of LDOM was assessed based on clinical and trichoscopic pictures. After six to 12 months, clinical improvement was observed in seven (100%) patients with grade 1 and in six (75%) patients with grade 2 alopecia. Trichoscopy revealed an increased hair thickness and growth of new hair (Figure 1). Two out of eight patients affected by grade 2 alopecia were not able to abandon the wig, but partial hair regrowth and increased thickness made them feel more confident. Dose reduction from 2.5 mg to 1.5 mg was necessary, at the three months follow up, in three females due to non-acceptable facial hypertrichosis. No other, including cardiological, side effects were reported. No cardiological tests were needed during and after the therapy. All patients refused a post-treatment scalp biopsy. The results of the present study is consistent with the study conducted by Kang et al. (5) who observed efficacy of combination of LDOM and topical minoxidil in patients with PCIA. In our study, LDOM used in monotherapy was effective. The limitation of the study is a small group of the pa- tients included into analysis and the lack of post-treatment histology which would allow to define improvement on pa- thology grounds. Further studies are needed to better clar- ify the mechanism of action of LDOM in patients affected by PCIA and to draw conclusions concerning optimal drug dosages. Conclusions To conclude, we believe that LDOM is a promising ther- apeutic option for patients with PCIA who do not benefit from the topical solution or report disadvantages related to friction on a delicate scalp with thin hair. References 1. Freites-Martinez A, Shapiro J, van den Hurk C, et al. Hair disorders in cancer survivors. J Am Acad Dermatol. 2019;80(5): 1199-1213. DOI: 10.1016/j.jaad.2018.03.056. PMID: 29660423. PMCID: PMC6186205. 2. Yang X, Thai KE. Treatment of permanent chemotherapy- induced alopecia with low dose oral minoxidil. Australas J Dermatol. 2016;57(4):e130-e132. DOI: 10.1111/ajd.12350. PMID: 25966934 3. Bhoyrul B, Asfour L, Lutz G, et al. Clinicopathologic Characteristics and Response to Treatment of Persistent Chemotherapy-Induced Alopecia in Breast Cancer Survivors. JAMA Dermatol. 2021;157(11):1335-1342. DOI: 10.1001 /jamadermatol.2021.3676. PMID: 34586345. PMCID: PMC8482302. 4. Vañó-Galván S, Pirmez R, Hermosa-Gelbard A, et al. Safety of low-dose oral minoxidil for hair loss: A multicenter study of 1404 patients. J Am Acad Dermatol. 2021;84(6):1644-1651. DOI: 10.1016/j.jaad.2021.02.054. PMID: 33639244. 5. Kang J, Lee JW, Kwon O. Efficacy of low-dose oral minoxi- dil in the management of anticancer therapy-induced alopecia in patients with breast cancer: A retrospective cohort study. J Am Acad Dermatol. 2023;88(5):1170-1173. DOI: 10.1016/j .jaad.2022.12.005. PMID: 36526083. Table 1. Characteristics of patients with persistent chemotherapy-induced alopecia treated with low dose oral minoxidil. Patients numbers females males 15 13 2 Age (years), mean (range) 49 (35-71) Disease breast adenocarcinoma lung adenocarcinoma myelodysplasia Hodgkin lymphoma 12 1 1 1 Taxane-based therapy docetaxel paclitaxel 3 7 Non-taxane based therapy carboplatin cisplatin cyclophosphamide dacarbazine doxorubicin epirubicin etoposide 5-fluorouracil vincristine vinorelbine 3 1 10 1 2 3 3 1 1 1 Targeted therapy pertuzumab trastuzumab 3 4 Alopecia grade grade 1 grade 2 7 8 Trichoscopy circle hairs / yellow dots hair thinning / empty follicules 3 15 Research Letter | Dermatol Pract Concept. 2023;13(3):e2023152 3 Figure 1. Clinical and trichoscopy images of a patient with persistent chemotherapy-induced alopecia (A,B) before treatment. (C,D) after 6 months of treatment with oral minoxidil 1.5 mg/day.