April 1, 2015

Can Laughter Therapy Reduce Radiation Dermatitis?

Study on cancer patients explores efficacy of laughter
According to this small study, laughter therapy alleviated symptoms of radiation dermatitis in breast-cancer patients, but in statistically nonsignificant ways. Should practitioners encourage laughter as therapy before larger clinical trials are performed?


Kong M, Shin SH, Lee E, Yun EK. The effect of laughter therapy on radiation dermatitis in patients with breast cancer: a single-blind prospective pilot study. Onco Targets Ther. 2014 Nov 4;7:2053-2059. 


Prospective, randomly assigned controlled clinical trial


Thirty-seven patients were prospectively enrolled in this study. Eligibility criteria included pathologically confirmed unilateral breast cancer without tumor invasion of the skin, completion of breast-conserving surgery with or without adjuvant chemotherapy, and treatment with postoperative radiation therapy at least 45 gray. Eighteen patients were assigned to the experimental group, and the other 19 patients were assigned to the control group. The patients in the experimental group received laughter therapy during radiation therapy. Laughter therapy was started at the onset of therapy and provided twice a week until completion of treatment. Patients in the control group received only radiation without laughter therapy. The women in the experimental group differed significantly from the control group in that they were older, more likely to have diabetes, and had larger breasts. All 3 of these factors are predictive of worse dermatitis.

Study Medication and Dosage

Laughter therapy as employed in this study consisted of a lecture on the benefits of laughter and group sessions that included active motion “designed to produce laugher, especially mirthful laughter and self-induced stimulated laugher.” Each session lasted 60 minutes. The patients were observed by staff, and those “who did not mirthfully laugh more than 10 times in each laughter therapy session were excluded from this study.” (Talk about pressure!) Patients who did not “enjoy the laughter therapy” were excluded from the trial.

Outcome Measures

A radiation oncologist who was blinded to subject assignment scored the grade of radiation dermatitis. The patients’ evaluation of pain within the radiation field was also assessed. Patients were examined at baseline and at weekly intervals from the start of radiation therapy until 8 weeks after its completion. At the initiation of therapy and 1 week after completion, serum levels of epidermal growth factor, transforming growth factor beta, and fibroblast growth factor were measured in all patients.

Key Findings

Three of the experimental group patients were excluded. Therefore 15 patients in the experimental group and 19 in the control group completed the study, and their results were analyzed (Table). 

Table. Maximum Grade of Radiation Dermatitis

Laughter Group


Control Group


35 (33.3%)7 (36.8%)
25 (33.3%)9 (47.4%)
15 (33.3%)2 (10.5%)
001 (5.3%)
In the experimental group, radiation dermatitis of grades 3, 2, and 1 developed in 5 (33.3%), 5 (33.3%), and 5 patients (33.3%), respectively. In comparison, in the control group, radiation dermatitis of grades 3, 2, 1, and 0 developed in 7 (36.8%), 9 (47.4%), 2 (10.5%), and 1 patient (5.3%), respectively. The experimental group exhibited a lower incidence of grade 2 or worse radiation dermatitis than the control group (33.3% vs 47.4%). While the experimental group had a lower incidence of grade 2 or worse radiation dermatitis than the control group (66.7% vs 84.2%), these differences did not reach statistical significance (P=0.053). The mean maximal pain scores in the experimental and control group were 2.53 and 3.95, respectively. The experimental group complained less of severe pain than the control group during radiation therapy; however, these differences were not statistically significant. In both univariate and multivariate analysis, the total dose of radiation therapy was significantly associated with severity of radiation dermatitis.

Practice Implications

While the results of this small pilot study suggest that the laughter therapy tested lowered risk of high-grade radiation dermatitis, these results did not reach statistical significance, so this raises the question: “Why are we reviewing this paper?” As the authors point out, “laughter therapy does not require large amounts of time or money and the side effects of laughter therapy are very limited, so we suggest that laughter therapy can be implemented easily and cost-effectively as complementary therapy in patients with breast cancer without confirmation of our favorable results.” This is one of those “It won’t hurt; it might help” situations where the potential benefits outweigh the potential drawbacks.
This is one of those ‘It won’t hurt; it might help’ situations where the potential benefits outweigh the potential drawbacks.
Kimata has reported that laughter has significant impact on a number of skin pathologies, in particular atopic dermatitis.1,2 In Kimata’s earlier studies, funny videos of Charlie Chaplin and Mr Bean were used as triggers. In this current trial, laughter was self-induced; the authors believe that the brain responds the same to both self-induced and externally stimulated laughter. This idea that all laughter has the same effect, though, is still just an assumption.
Laughter upregulates the genes that control natural killer cells.4 This increase in natural killer cell activity associated with this upregulation appears to be more related to how much the subjects enjoyed the movie rather than the intensity of the laughter the viewing provoked—ie, “the experiential aspects of laughter rather than with the expressive aspects”5— raising the question as to why the authors of the current radiation study chose to exclude experimental subjects who appeared to be inadequately mirthful.
A January 2015 paper reported that laughter therapy was associated with improvements in “factors such as general health (P=0.001), somatic symptoms (P=0.001), insomnia and anxiety.”6 This was a randomized controlled trial that had enrolled 72 senior citizens who attended events at a retirement center. Half were enrolled into an experimental laughter group, and half served as controls. Data were collected using a general health questionnaire. The experimental group attended laughter therapy programs consisting of 90-minute sessions twice a week for 6 weeks.6
Laughter may not have been definitively proven to reduce radiation dermatitis, but as it has clear benefit for general health, it still seems prudent to encourage this therapy.
Few patients have easy access to the sort of “laughter therapy sessions” employed in these trials, but most, if not all, do have access to online videos and movies these days. The latter may be as effective, if not more effective. In our practice, we encourage patients to watch something online that makes them laugh for 30 minutes a day. We also encourage them to engage regularly in the rather old-fashioned practice of telling jokes. Our experience is that laughter therapy does actually have side effects—that patients who actively utilize this therapy appear to be happier.

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  1. Kimata H. Reduction of allergic responses in atopic infants by mother’s laughter. Eur J Clin Invest. 2004;34(9):645-646.
  2. Kimata H. Laughter counteracts enhancement of plasma neurotrophin levels and allergic skin wheal responses by mobile phone-mediated stress. Behav Med. 2004;29(4):149-152.
  3. Mora-Ripoll R. The therapeutic value of laughter in medicine. Altern Ther Health Med. 2010;16(6):56-64.
  4. Hayashi T, Tsujii S, Iburi T, et al. Laughter up-regulates the genes related to NK cell activity in diabetes. Biomed Res. 2007;28(6):281-285.
  5. Takahashi K, Iwase M, Yamashita K, et al. The elevation of natural killer cell activity induced by laughter in a crossover designed study. Int J Mol Med. 2001;8(6):645-650.
  6. Ghodsbin F, Sharif Ahmadi Z, Jahanbin I, Sharif F. The effects of laughter therapy on general health of elderly people referring to Jahandidegan Community Center in Shiraz, Iran, 2014: a randomized controlled trial. Int J Community Based Nurs Midwifery. 2015;3(1):31-38.