Deodorant use and the risk of skin toxicity in patients undergoing radiation therapy for breast cancer: A meta-analysis

Abstract

The effect of deodorant on Breast Cancer (BC) therapy has generated significant interest in the scientific community. The aim of this study was to analyse all randomized controlled trials investigating any adverse effects associated with deodorant use. Specifically, we aimed to investigate the effect of regular deodorant use on adverse effects to breast cancer treatment. A database search was conducted following the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines [ [1] Stroup D.F. Berlin J.A. Morton S.C. Olkin I. Williamson G.D. Rennie D. et al. Meta-analysis of observational studies in epidemiology: a proposal for reporting. Meta-analysis Of Observational Studies in Epidemiology (MOOSE) group. JAMA. 2000; 283: 2008-2012 Crossref PubMed Scopus (14663) Google Scholar ]. The databases, MEDLINE, EMBASE, PubMed, Current Contents Connect, and Google Scholar (1950–2012), were searched using the search terms “deodorant” AND “breast cancer” OR “breast neoplasm” OR “breast carcinoma”. There was no language restriction and we did not search for unpublished literature. The inclusion criteria included studies that had a risk estimate, and an internal control group that had not been diagnosed with breast disease. A random effects model was used to calculate a pooled odds ratio for the effect of deodorant on breast cancer. Four studies were identified in the literature review that investigated the effect of regular deodorant use on therapeutic adverse events. Specifically, these studies investigated whether or not deodorant increased the risk of skin toxicity in patients undergoing radiation therapy. The four randomized controlled trials met the inclusion criteria with three studies favouring the use of deodorant [ 2 Bennett C. An investigation into the use of a non-metallic deodorant during radiotherapy treatment: A randomised controlled trial. Journal of Radiotherapy in Practice. 2009; 8: 3-9 Crossref Scopus (21) Google Scholar , 3 Theberge V. Harel F. Dagnault A. Use of axillary deodorant and effect on acute skin toxicity during radiotherapy for breast cancer: a prospective randomized noninferiority trial. International Journal of Radiation Oncology, Biology, Physics. 2009; 75: 1048-1052 Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar ] while the final study favoured the control group [ [4] Watson L. Gies D. Thomas E. Thomas B. Randomized Control Trial: Evaluating Aluminum-Based Antiperspirant Use, Axilla Skin Toxicity, and Reported Quality of Life in Women Receiving External Beam Radiotherapy for Treatment of Stage 0, I, and II Breast Cancer. International Journal of Radiation Oncology Biology Physics. 2012; 83: e29-e34 Abstract Full Text Full Text PDF PubMed Scopus (31) Google Scholar ]. The pooled relative risk did not identify any association between skin toxicity and deodorant use (RR 1.01, 95% CI 0.82–1.25, I2= 0.00, p = 0.44) (Fig. 1). We have found no evidence that deodorant adversely affects BC treatment. While the exact mechanism linking skin toxicity to deodorant use is yet to be determined, a number of mechanisms have been hypothesised. The first hypothesis involves deodorant acting to increase the concentration of the radiation applied to the skin while the second hypothesis focuses on an adverse reaction between the metallic components of deodorant and the external radiotherapy [ [6] Bolderston A. Lloyd N.S. Wong R.K.S. Holden L. Robb-Blenderman L. Supportive Care Guidelines Group of Cancer Care Ontario Program in Evidence-Based C: The prevention and management of acute skin reactions related to radiation therapy: a systematic review and practice guideline. Support Care Cancer. 2006; 14: 802-817 Crossref PubMed Scopus (179) Google Scholar ]. However, a study by Burch et al. did not identify any significant abnormalities in the concentration of radiation in the skin associated with deodorant use [ [7] Burch S. Parker S. Vann A. Arazie J. Measurement of 6-MV x-ray surface dose when topical agents are applied prior to external beam irradiation. International Journal of Radiation Oncology Biology Physics. 1997; 38: 447-451 Abstract Full Text PDF PubMed Scopus (39) Google Scholar ]. In addition, there was no difference in surface radiation dose associated with metallic or non-metallic deodorants. These findings are congruent with the results of this study in finding no increase in skin toxicity associated with the topical application of deodorant. The strengths of this study include a thorough literature review, precise inclusion criteria and inclusion of studies in any language. On the other hand, the lack of primary studies and the quality of the available studies was the main weakness of this analysis. With only four primary studies available we recommend further high quality studies be undertaken to definitively exclude an association between skin toxicity and deodorant use. There is no evidence at this stage that deodorant increases the rate of adverse events in patients undergoing radiation therapy for BC.