Cancer is not a contagious disease. Therefore, the scope of transmitting cancer from a patient to a healthy person is not possible. The immune system of the human body can identify foreign cells including cancer cells and destroy them. But following are certain circumstances where the minimal scope of cancer transmission can possible from one person to another.
During organ transplantation
Organ transplant from a cancerous patient to another person can cause transmission of cancer. But this condition usually occurs in immunocompromised persons or individuals who are under medications that weaken the immune system functioning. In general, doctors prescribed Immune system suppressed medicines so that bodily immune function cannot attack or destroy transplanted organs. Therefore, organ donors must be clinically screened to reduce the risk of cancer transmission from donor to recipient.
However, many solid-organ recipients had experienced cancer after transplantation, though the donor did not have any history of cancer. This is possible because immune system suppressive medications given during organ transplantation can reduce the ability to pre-detect the cancer cell and destroy them.
In a rare instance, cancer can transfer from mother to fetus during pregnancy. But clinical evidence suggested that melanoma, a type of skin cancer has the probability to transmit from mother to fetus.
Germ causing infections increase the risk of cancer
Some cancers are more common in patients who have certain specific types of infections. For example:
Specific types of human papillomaviruses (HPVs) have a close association with cancers that develops in the cervix, vulva, vagina, anus, penis. Apart from these, certain types of mouth, throat, head, and neck cancers. But the risk is increased among smokers or frequent alcohol drinkers or individuals who lead a poor lifestyle.
Epstein-Barr virus (EBV) infection has a link with nasopharyngeal cancer, Hodgkin lymphoma, stomach lymphoma, and Burkitt lymphoma.
Hepatitis B virus (HBV) and hepatitis C virus (HCV) have an association with chronic liver infections and that increase the risk of liver cancer.
Kaposi sarcoma herpes which is also known as Human herpes virus Type 8 (HHV-8) has been linked with Kaposi sarcoma. However, usually AIDS patients who have HIV (human immunodeficiency virus) infection with HHV-8 develop Kaposi sarcoma. Apart from this, individuals who are taking immunosuppressant medications with HHV-8 infection can also develop Kaposi sarcoma.
lymphocytic leukemia and non-Hodgkin lymphoma can occur in patients infected with Human T-lymphotropic virus-1 (HTLV-1).
HIV patients have a tendency to develop certain lymphomas, Kaposi sarcoma, and invasive cervical cancer. HIV weakens the immune system and causes AIDS.
These viruses are transmitted from one infected patient to others through blood or sex. But the viral infections alone cannot cause cancer until the infected person has a weak immune system or other lifestyle factors like smoking.
A certain bacterial infection like the presence ofHelicobacter pylori infection has a link with certain stomach cancer. The chronic infection damages the stomach lining and increases the stomach cancer risk.
The human body is a host of certain parasitic worms and can increase the risk of certain cancer development. Parasites have been linked with bladder cancer and bile duct cancers. These incidences are more common in western countries.