Background: The current study describes the results of a double blind, placebo-controlled, randomized, single crossover trial of the treatment of patients with postmastectomy lymphedema (PML) with low-level laser therapy (LLLT).

Methods: Participants received placebo or one cycle or two cycles of LLLT to the axillary region of their affected arm. They were monitored for reductions in affected limb volume, upper body extracellular tissue fluid distribution, dermal tonometry, and range of limb movement.

Results: There was no significant improvement reported immediately after any of the treatments. However, the mean affected limb volume was found to be significantly reduced at 1 month or 3 months of follow-up after 2 cycles of active laser treatment. Approximately 31% of subjects had a clinically significant reduction in the volume of their PML-affected arm (> 200 mLs) approximately 2-3 months after 2 cycles of treatment. There was no significant effect of placebo treatment, or one cycle of laser treatment, on affected limb volume. The extracellular fluid index of the affected and unaffected arms and torso were reported to be significantly reduced at 3 months after 2 cycles of laser therapy, and there was significant softening of the tissues in the affected upper arm. Treatment did not appear to improve range of movement of the affected arm.

Conclusions: Two cycles of laser treatment were found to be effective in reducing the volume of the affected arm, extracellular fluid, and tissue hardness in approximately 33% of patients with postmastectomy lymphedema at 3 months after treatment.