Lymphatic pumping technique in mice alters blood parameters and metastatic melanoma in an age-dependent manner

Therapeutic touch applied to primary tumors can increase metastasis. The goal of this project was to determine whether touch applied to metastatic tumors also increases metastasis. We evaluated touch on a mouse model of experimental metastasis using a manual treatment called Lymphatic Pumping Technique (LPT), which increases lymphatic fluid flow and is contraindicated in patients with cancer. The LPT, or a sham treatment, was administered for 5 minutes while the mice were anesthetized with vaporized isoflurane. Young adult (3 months old) and aged (20–24 months old) mice received daily sham or LPT treatments for 7 days prior to the injection of 200k B16F10-luc2 mouse melanoma cells into the tail vein, then treated every other day for 21 days. In middle-aged (9–11 months old) mice, we waited 8 days after tumor injection to start treatments and assessed the effect of LPT on immunotherapy efficacy. These mice also received either LPT or sham every other day, along with four doses of 200 µg anti–PD-1 or isotype control antibody. LPT did not increase tumor growth or spread in any of the experiments. Surprisingly, LPT was negatively associated with metastasis in young and middle-aged mice, without enhancing or diminishing the efficacy of immunotherapy. In mice without cancer, LPT rapidly elevated red blood cell, white blood cell, and platelet counts in young, but not middle-aged, animals. Taken together, these findings suggest that therapeutic touch near metastatic tumors does not worsen disease and may confer an age-dependent benefit.