Long-term benefits have also been associated with those patients who receive surgery, radiotherapy, and temozolomide chemotherapy. However, much remains unknown about why some patients survive longer with glioblastoma. Age under 50 is linked to longer survival in GBM, as is 98%+ resection and use of temozolomide chemotherapy and better KPSs. A recent study confirms that younger age is associated with a much better prognosis, with a small fraction of patients under 40 years of age achieving a population-based cure. Cure is thought to occur when a person's risk of death returns to that of the normal population, and in GBM, this is thought to occur after 10 years.