Abstract LB-422: Photodynamic ablation of lymphatic vessels and intralymphatic cancer cells prevents metastasis

Abstract

Abstract The dissemination of tumor cells (metastasis) from the primary tumor is the principal cause of death in cancer patients. The lymphatic vessels serve as a key conduit for metastasizing tumor cells, which often colonize the lymph nodes first. Although the primary tumor and lymph nodes invaded by tumor cells are removed during surgery, tumor cells inside lymphatic vessels are not removed. Here, we demonstrate tumor cell growth inside lymphatic vessels in mice bearing mouse melanoma tumors or human lung tumors and in a human melanoma patient, suggesting that these in-transit tumor cells give rise to metastases. We selectively destroyed lymphatic vessels using photodynamic therapy with the benzoporphyrin derivative verteporfin in mice and pigs. Destruction of tumor-draining lymphatic vessels also eradicated intralymphatic tumor cells, and prevented in-transit metastasis of mouse melanoma cells and subsequent relapse. Photodynamic therapy, when combined with anti-lymphangiogenic therapy, prevented further tumor invasion of lymphatic vessels and may provide a way to eradicate in-transit tumor cells in patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-422. doi:10.1158/1538-7445.AM2011-LB-422