London: Adolescents and young adults have a lower chance of surviving some common types of cancer than children, finds a new study on cancer survival across Europe. "The good news is that the number of children, adolescents and young adults surviving for at least five years after diagnosis has risen steadily over time in Europe," said lead author Annalisa Trama from The National Institute of Cancer in Milan, Italy. "However, we found that adolescents and young adults still tend to die earlier than children for several cancers common to these age groups, particularly blood cancers like leukaemias and non-Hodgkin's lymphoma (NHL)," Trama added. According to researchers, the variations in survival rates between both age groups are due to a number of factors including delays in diagnosis and treatment, a lack of treatment guidelines and clinical trials specifically for teenagers and young adults, as well as differences in the biology of some cancers. For the study, published in the journal The Lancet Oncology, the team analysed data from 27 European countries on nearly 56,505 cancer cases in children, 3,12,483 in adolescents and young adults and 35,67,383 in adults. The findings showed that overall, survival was significantly worse for adolescents and young adults compared with children for eight relatively common cancers affecting both age groups -- acute lymphoid leukaemias, acute myeloid leukaemias, Hodgkin's lymphoma, Non-Hodgkin lymphoma (NHL), astrocytomas (type of brain tumour), Ewing's sarcoma of bone, rhabdomyosarcoma (cancer of soft tissue like muscle) and osteosarcoma (the most common type of bone cancer). But for cancers with a better prognosis, the five-year survival rates were found to be higher in teenagers and young adults at 82 percent compared with 79 percent in children. Further, adolescents and young adults were found to have a survival advantage over adults for almost all major cancers affecting both age groups, supporting the idea that younger patients with few other illnesses are likely to fare better than older patients. However, adolescents and young adults were found at a survival disadvantage for breast and prostate cancer. "This reflects the fact that younger women often present with larger, higher-grade cancers that are more advanced, and that prostate disease tends to be more aggressive in younger men," Trama noted.