cancer itself is not contagious, in some cases viruses that are infectious can lead to the development of cancer. Some of these include the Human Papillomavirus virus that can cause cervical cancer through sexual transmission, Hepatitis B and Hepatitis C which can cause liver cancer through sexual transmission or the use of infected needles and Helicobacter pylori bacteria which can cause stomach cancer through germs which enter and live in the digestive tract.
The only situation in which cancer can spread from one person to another is in the case of organ or tissue transplantation. A person who receives an organ or tissue from a donor who has been a cancer patient may be at increased risk of developing a transplant-related cancer in the future.
There is no age limit for undergoing cancer treatment and elderly patients can respond as well to treatment as compared to their younger counterparts. Therefore, patients with cancer should receive the treatment that is best suited to their condition, regardless of age.