New Delhi, Jul 08 (ANI): Over the years, incidences of cancer have spiked considerably, affecting millions of people worldwide. Out of the various types of cancers, high-grade cancers are those that are considered aggressive, as they spread rapidly. Metastasis is defined as the spread of cancer cells to other parts of the body, away from the primary area of formation (where it started). This occurs through the lymph system or through blood, which then forms tumours in other parts. These newly-formed tumours are called secondary tumours. Treatment for metastatic cancer depends on the type of cancer, its place of origin of metastasis, the size of the tumour and other factors. Treatment typically aims at slowing down the growth and the spread. Treatment for these cancers requires systemic therapy that aims at reaching cancer cells at affected parts of the body through chemotherapy, hormonal therapy and immunotherapy.