Please explain why radiation is given as a treatment protocol for radiation induced cancer?

Because it works. Some wavelengths of radiation damage the genome. This is why these wavelengths can produce cancer. In the same way, once a cancer has formed (and this is dumb luck), it can often be contained by giving a huge dose of radiation. Think. Your question is like asking, "why would a surgeon use a knife to treat injuries from a knife wound?".

Related Questions

If caused, which age is more affected by radiation induced cancer? Young or old?

Unclear, but. Radiation exposure and related cancers are thought to take years to develop. So that younger patients are at greater risk. Since these kinds of cancers can take years after exposure they occur in older patients. Necessary x-rays and tests are important. The newest equipment tries to minimize radiation exposure. Read more...
Young. A young person has more time to suffer the consequences of dna damage from radiation. Read more...
Young. A young person has more time to suffer the consequences of dna damage from radiation. Read more...

How long does it takes to get radiation induced cancer? Should I worry after 5 to 10 years as I had on chest CT scan month ago with 4.8msv dose?

Not to worry. Radiation-induced cancer typically takes prolonged exposure to small doses of radiation, measured in rads. The chances of your developing a cancer from a single ct are reassuringly small. I would refer you to this website..http://hps.org/publicinformation/ate/faqs/radiation.htm. I hope this helps! Read more...
May not even happen. The average ct scan in the us exposes us anywhere between 3 and 10 msv. A dose of 10 msv increases the risk of getting any cancer by 0.1% and the risk of fatal cancer by 0.05%. According to the national research council and the U.S. Fda, any person has a 20% risk of dying from cancer in their lifetime. One ct scan of 10msv would increase the chance to 20.05%. Not a big risk. Don't worry too much. Read more...

Can one chest CT scan cause skin cancer later in life? Should I worry about radiation induced cancer from one CT scan?

CT and skin cancer. One ct will probably not cause skin cancer later in life. You should probably not worry about the radiation from just one ct in your lifetime. Don't forget that going out in the sun gives you exposure to radiation (and vitamin d as well!). Read more...