|Invasion is defined as the forcible occupation of the premises without prior intimation. It affects the natural working environment. It is a direct form of cancer spreading to space surrounding nerves. It is concerned with head, neck, prostate gland and colorectal organ. Prediction of disease is very difficult. It can be treated surgically and by using radiotherapy management. Peer review refers to the work done during the screening of submitted manuscripts and funding applications. This process encourages authors to meet the accepted standards of their discipline and reduces the dissemination of irrelevant findings, unwarranted claims, unacceptable interpretations, and personal views. Publications that have not undergone peer review are likely to be regarded with suspicion by academic scholars and professionals.