What is the youngest age for stomach cancer?

Very young: The vast majority are in adults, but rare forms, especially when inherited, can develop in <10 year old children.

14: Stomach cancer is very rare before age 30. There is a condition called hereditary diffuse gastric cancer (hdgc) which is particular deadly form of the disease and is transmitted by an autosomal dominant gene. The average age of onset of hdgc is 38 years, with a range of 14-69 years.

Depends: 90% of all gastric cancer occur spontaneously and have an average age of onset of ~65. However, 10% of gastric cancers are of a hereditary type and in these families the average age of onset is in the 30's with some individuals developing gastric cancer in their teens.