THE EFFECT OF LYMPHATIC PUMP TECHNIQUE ON PRIMARY TUMOR GROWTH IN RATS

Purpose (a): Background: Osteopathic Physicians perform lymphatic pump treatments (LPT) to improve lymphatic circulation, enhance immunity and reduce hospital stay in patients with infection and edema. Cancer is a contraindication for the use of LPT, which limits clinical practice; however, there are no published studies to support this conclusion. The purpose of this study was to determine if LPT enhances primary tumor growth. Specifically, we hypothesized that LPT would not increase the size of primary breast tumours. Methods (b): Breast cancer was induced in female rats by subcutaneous injection in the right mammary fat pad with MTLn3 tumor cells. The infected rats were randomized into Control Diseased (Dz), Sham LPT (Sham), and LPT. Healthy(Hy) animals were also included for disease comparison. Rats were weighed weekly to calculate percent body weight change. LPT and Sham were performed as previously described under isoflurane anesthesia on days 14 to 24 post-induction. On day 25 the rats were euthanized and cardiac puncture was performed for a blood differential count. The primary tumor, spleen, lung and axillary lymph nodes(LNs) were also removed and weighed. Results (c): There was no change in primary tumor size across the groups. Body weight increased in all groups until day 14. Of interest, Dz and Hy continued to gain weight while Sham and LPT decreased in size between days 14-25 of disease. There were no differences between groups in the size of the opposite LN, spleens or lung tissue. However, the adjacent LN in Dz, Sham and LPT increased in size compared to Hy, suggesting sentinel node disease. The blood differential showed leukocytosis with predominant neutrophils in Dz compared to Hy, indicating a cancer-induced inflammatory response. Sham and LPT response were lower in comparison to Dz, suggesting the inflammatory response was impaired in these animals. Conclusions (d): Our data demonstrates that LPT did not enhance primary tumor growth. MTLn3 induced an inflammatory response, which was impaired during Sham and LPT; however, the effect of this impairment on disease metastasis was not measured. In addition, Sham and LPT induced weight loss during disease. Anesthetics have been shown to suppress appetite and immunity. This may account for the decreased body weight and immune response in Sham and LPT. Future studies on metastasis and secondary growth are required to ascertain whether LPT is safe in patients with breast cancer.