AbstractPurposeThis article aims to study the effect of Low‐Level Laser Therapy (LLLT) on arm lymphedema in patients who have breast cancer.Methods and MaterialsTwenty‐three patients were selected in a nonrandomized phase‐2 clinical trial. After measuring the circumference of the affected and unaffected limbs at 6‐points, the volume of the limbs, the degree of mental symptoms on visual analog scale by the patient upon entering the study, and performing an ultrasound on the patient's axilla to locate the fibrotic areas, a low‐level laser device at a therapeutic dose of 2 J/cm2was used to treat the patients three times a week for 4 weeks, and after an 8‐week gap, for another similar period. Measurement of circumference and volume of affected and unaffected limbs and mental symptoms were carried out at the end of the 4th week, the beginning of the 12th week, and the end of the 16th week, and the obtained results were compared with those before the treatment.ResultsWe noted that the average reductions in the circumference and volume of the affected limb, as compared with the unaffected limb, were about 16% and 21.7%, respectively, and improvement in the patient's mental symptoms was about 32%. Another notable observation was the great enthusiasm of most patients to continue their treatment, particularly from the second cycle onward.ConclusionsLLLT can, at least in association with current standard methods, be used for arm lymphedema to introduce further reductions in pain and volume.