The objective of the present invention is to provide a method and a means of rapidly and reliably detecting lymph node metastasis in cancer or the risk of lymph node metastasis. Specifically, the present invention provides a method and a rapid determination kit for detecting lymph node metastasis in cancer or its risk by identifying a certain genetic polymorphism of the human CRP gene, and it is clinically significant in determining the treatment strategy, because effective prediction/determination can be made regarding lymph node metastasis, which is an important phenomenon in cancer progression.