New cases of cancer have been rising among younger people, worrying patients and doctors about causes. A new study suggests increasing numbers of cases of early onset cancer are largely due to improved and more routine screening, while mortality rates among younger people haven’t changed.

The study, published Monday in JAMA Internal Medicine, compared rates of new diagnoses over the past three decades to mortality rates of the fastest-rising cancers in adults under 50. 

Of the eight cancers the research team studied, only two, colorectal and endometrial, showed increases in deaths. Other cancers included thyroid, anal, pancreatic, kidney, myeloma and small intestine. While breast and kidney cancers have increased in incidence, the mortality rates across all age groups have decreased in recent years.