do adenomas develop?
Adenomas are not present at birth. Adenomas generally begin around
puberty, that is, from the age of 10-12. This is very different
from the more common history of a 50- or 60-year-old person who
may develop one or two adenomas. Most people with FAP are diagnosed
in their teens or early 20's. It is estimated that only 1% of all
bowel cancer is due to FAP.
Two things may happen to adenomas over time: they increase in size
and number. Adenomas form initially in the rectum and lower colon.
Some people have hundreds or thousands of adenomas while others,
particularly adolescents, may have fewer adenomas. One hundred polyps
is the average number of polyps in a person with FAP but this depends
on how old he or she is. This can be an important clue to treatment.
Without early diagnosis and treatment, the risk of colon cancer
is 100%. FAP is a pre-cancerous disease because 1) adenomas
will change to cancer in approximately 5 to 10 years and 2) prevention
of colon cancer is possible.
Adenomas in a segment of colon.