Kong, M., Shin, S.H., Lee, E., & Yun, E.K. (2014). The effect of laughter therapy on radiation dermatitis in patients with breast cancer: A single-blind prospective pilot study. OncoTargets and Therapy, 7, 2053–2059. 

To measure the effectiveness of laughter therapy for preventing radiation-induced dermatitis in patients with breast cancer who are receiving radiation therapy (RT)

Thirty-seven patients were enrolled in the study. Eighteen patients were assigned to the experimental group, which received laughter therapy during radiation treatment, based on their preference to participate. Nineteen patients who did not want to participate in the laughter therapy were assigned to the control group. The laughter therapy started at the beginning of therapy and continued until completion of RT. In this three-part intervention study, patients were assessed by staff observation or a questionnaire before and after laughter therapy. Patients in the control group were not allowed to use any prophylactic creams or lotion (p. 2054).

• N = 37  
• MEAN AGE = Experimental group: 59.1 years, control group: 49.3 years
• FEMALES: 100%
• KEY DISEASE CHARACTERISTICS: Confirmed pathology of unilateral breast cancer; no tumor invasion of the skin; complete breast conserving surgery with or without adjuvant chemotherapy
• OTHER KEY SAMPLE CHARACTERISTICS: Postoperative RT dose greater or equal to 45 Gy without bolus, no concurrent chemotherapy, no history of RT to the chest wall, no connective tissue disorders, no rashes or unilateral wound

• SITE: Not stated/unknown    
• SETTING TYPE: Not specified    
• LOCATION: Kyung Hee University Medical Center, Korea

PHASE OF CARE: Active antitumor treatment

Single-blind, two-group, prospective, nonrandom design

• Skin toxicity grading using the Radiation Therapy Oncology Group (RTOG) was completed by a radiation oncologist who was blinded to the subject’s assignment.
• Pain was evaluated using a visual analog scale (VAS). 
• Questionnaires were completed through staff observation.

The authors stated that, although laughter therapy showed favorable therapeutic efficacy in preventing dermatitis and alleviating pain, they could not draw a definite conclusion because of the lack of statistical significance. An additional study of a larger sample group is necessary. Some limitations exist in this small pilot study, which makes it difficult to interpret the data and draw conclusions.

This single-blind, prospective, pilot study showed that laughter therapy can be beneficial in preventing radiation-induced dermatitis in patient with breast cancer; however, a well-designed randomized study with a larger sample size is needed to confirm the efficacy of the study.

• Small sample (< 30)
• Risk of bias (sample characteristics)
• Key sample group differences that could influence results
• Eligibility criteria did not address whether patients had pre-existing medical histories of anxiety/depression or mood disorder/lability.
• Eligibility criteria included patients with or without adjuvant chemotherapy, which seems to be a potential factor for skewed results, perhaps because with chemotherapy, side effects can be long-lasting (i.e., peripheral neuropathy, alopecia, mood changes). This might affect patients undergoing laughter therapy.
• The authors noted that the assignment of patients was \"based on the patients’ preferences. The patients who wanted to receive laughter therapy were assigned to the experimental group, and the others were assigned to the control group\" (p. 2054). This might skew the data, presuming that patients who wanted the therapy were already biased and perhaps likely to receive the most benefit of the therapy (self-fulfilling prophecy in a way).
• Not allowing \"any prophylactic creams or lotions for radiation dermatitis\" (p. 2054) in either group might be seen as withholding treatment and unethical.
• Some patients received an electron boost; others had three-field treatment.
• Grade 3 dermatitis in 12 patients (35.3%) seems unacceptable/intolerable because no patients received skin care using topical emollients.
• The patient characteristics included smokers, nonsmokers, and diabetics, which might affect patient skin reactions and healing (i.e., poorer or delayed wound healing in smokers and possibly diabetics).
• The study was not conducted in the United States. This would likely prove more difficult in recruiting patients because the skin reactions were not being treated with topicals.
• No discussion regarding the use of pain medications existed. Patient use of pain medications (even over-the-counter analgesics, such as acetaminophen or ibuprofen, or hydrocodone, etc.) might influence their laughter response to the treatment and, therefore, the efficacy the authors cite.

Laughter therapy may have a beneficial effect on patients with radiation dermatitis undergoing breast cancer treatment. However, not enough data exist to support the sole use of this intervention during treatment.