Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer.
A malignant tumor contrasts with a non-cancerous benign tumor in that a malignancy is not self-limited in its growth, is capable of invading into adjacent tissues, and may be capable of spreading to distant tissues.
A benign tumor has none of those properties, but may still be harmful to health. The term benign in more general medical use characterizes a condition or growth that is not cancerous, i.e. does not spread to other parts of the body or invade nearby tissue. Sometimes the term is used to suggest that a condition is not dangerous or serious, although this is not always the case.
Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis. Malignant tumors are also characterized by genome instability: cancers, as assessed by whole genome sequencing, frequently have between 10,000 and 100,000 mutations in their entire genomes. Cancers usually show tumour heterogeneity, containing multiple subclones. They also frequently have reduced expression of DNA repair enzymes due to epigenetic methylation of DNA repair genes or altered microRNAs that control DNA repair gene expression.
Tumours often manifest as a visible lump on the body. A mammogram or MRI scan can be used to determine or detect a suspected tumour, particularly if there is no visible lump. On the other hand, symptoms are felt internally by the individual such as fatigue or changes in appetite. These include bacterial causes, fungal and parasitic causes, and viral causes. The main purpose of inflammation is to repair tissue, defend the body against pathogens and regenerate cells.
Post-transplant malignancy
Individuals who undergo organ transplant surgery have an increased risk of developing malignancy in comparison to the general population. This is linked to recipients being at a higher risk when exposed to traditional risk factors as well as, the type and intensity of the operation, the duration of their immunosuppression post-operation, and the risk of developing oncogenic viral infections.
Surgery
Surgery can help manage or treat malignancy by either removing the tumour, localising it and/or determining whether there has been a spread to other organs. When undertaking surgery for malignancy, there are six major objectives which are considered. It is commonly used to identify and localise cancers as when it is under activation of blue light the red fluorescence of the malignant tumour (due to the HPD) can be observed easily.
The combination of HPD with red light (photoradiation) has been used on various malignant tumours including malignant melanomas and carcinomas on a range of different organs including the breast and colon. The singlet oxygen is a cytotoxic agent The treatment process also utilises HPD's capability of accumulating at higher levels in malignant tissues compared to most other tissues. The use of this treatment type largely depends on the fact that malignant and normal cells have differing responses to the energy source used. It can be administered through "injection, intra-arterial (IA), intraperitoneal (IP), intrathecal (IT), intravenous (IV), topical or oral". It targets the cellular mechanisms which allow the development of malignancy throughout the body. There are no specific areas which are targeted and so, there is a lack of differentiation between normal and malignant cells, The risk of developing malignancy is 20.2%. In 2018, 18 million patients were diagnosed with a malignant tumour with lung, breast and prostate being the most common form. The number of smokers in China is rapidly increasing with tobacco killing approximately 3000 people each day. In the 15–49-year-old age bracket the most common form of malignancy is breast cancer with liver and lung cancer following.