PATHOLOGY

Detailed explanation-1: -Metastasis. In metastasis, cancer cells break away from where they first formed (primary cancer), travel through the blood or lymph system, and form new tumors (metastatic tumors) in other parts of the body.

Detailed explanation-2: -When tumour cells metastasize, the new tumour is called a secondary or a metastatic tumour, and its cells are similar to those in an original or a primary tumour. So, the correct answer is ‘Spread of cancer cells to new sites’.

Detailed explanation-3: -Cancer metastasizes due to several factors, namely attack by the immune system, lack of oxygen and necessary nutrients, large amounts of lactic acid produced by glycolysis and increased cell death. Therefore, the majority of the presently available treatments for cancer also bear the potential to induce metastasis.