If lymph nodes are malignant, has the cancer spread?

If you have a lymph node or nodes that are malignant, this means they contain cancer cells. So, the cancer has spread from where it started to the lymph nodes. A cancer often spreads first to the lymph nodes nearest to it. During surgery to remove a tumour the surgeon may also remove the nearest group of lymph nodes. 

Having cancer in the lymph nodes means that there is a higher risk of the cancer spreading or coming back somewhere else in the body in the future. But it does not mean that the cancer has definitely spread or will come back. There is a chance that all the cancer cells are gone. 

For many cancers, doctors give radiotherapy, chemotherapy or biological therapies after surgery.  The aim of this treatment is to try and kill any cancer cells left behind in the lymph nodes or elsewhere in the body.  Doctor call this type of treatment adjuvant therapy.