Survivors of cancer during childhood remain at risk of developing the disease again, and need to have a 'good follow-up health care', Australian scientists have said.

Researchers reviewed cases of around 900 childhood cancer survivors treated at the Sydney Children's Hospital from 1972 to 1999, with records of new cancer cases and early deaths.

The study found out childhood cancer survivors had an almost five-fold increased rate of developing new cancer and they were 7.5 times more likely to die early, Australian news agency AAP reported Sunday.

Lesley Ashton, head of the Molecular Epidemiology Programme at the Children's Cancer Institute Australia, said this could often be traced to the life-saving therapies they received in their youth.

'Our results highlight that it is important for cancer survivors to be aware of the risk factors for complications of treatment and second cancers, and maintain good follow-up health care,' Ashton wrote in the Medical Journal of Australia.

He said two-thirds of survivors of childhood cancer would go on to develop a related chronic health condition later in life, and for a small number it would be life threatening.

This included new tumours - particularly thyroid, breast, bone or brain cancers. Research was under way to isolate the genes which play a role in determining which survivors would develop new cancers, he said.