Effect of Negative Lymph Node Dissection on Overall Survival of Mice Inducted with 4T1 Breast Cancer

Abstract

Background: In solid cancer cases, surgery is the effective treatment for removing the mass and evaluating the locoregional lymph nodes. The extension of lymph node dissection (LND) is a challenging question in cancer surgery. At present, limited LND is a high topic accepted in breast cancer surgery. It is interesting to know that with limitations in LND in breast cancer surgery, there are no animal studies on this topic. Objectives: This study investigated local management with and without LND on the overall survival (OS) of mice inducted with 4T1 breast cancer cells. Methods: Fifty-four inbred female Balb/C mice were divided into seven groups, except for group seven as the healthy control group; all were injected with 4T1 breast cancer cells. Ten (early diagnosis and management) and twenty days (late diagnosis and management) following injection, in groups 1 and 2, the leg was amputated above the knee; in groups 3 and 4, inguinal LND was done without amputation (AMP). In the group five, the combination of AMP and LND was performed. Group six was only injected with tumor cells, and group seven was left intact without intervention. Finally, metastasis and survival time were evaluated. Results: Survival time in group 1, group 2 (local Management), and group 5 was significantly higher compared to the control group (P < 0.005). However, LND alone did not improve survival, and its combination with AMP did not provide additional survival benefits over AMP alone. AMP treatment significantly reduced the amount of breast tumor cell metastasis (P < 0.002), while LND did not affect metastasis. Also, simultaneous treatment of leg AMP and LND reduced the metastasis rate of breast tumor cells (P < 0.05). Conclusions: The most effective step in solid tumors is removing cancer (local management) as soon as possible. Evaluating the regional lymph nodes is the next step. Lymph nodes should be removed if tumors involve lymph nodes. However, removing negative lymph nodes will not affect OS. More investigations are recommended in this field.