how long have I had cancer?
http://www.surgery.wisc.edu/breast_info/devt.html
How long does breast cancer exist before being discovered? Most women are
shocked to find out that they have had their breast cancer for years before it
was discovered. Cancer growth is measured in doubling times. One doubling time
is the amount of time that it takes for the mass of cancer cells to double in
size. It takes about 23 doubling times to go from one cancer cell to become a
large enough mass to be seen on a mammogram, and about 30 doubling times to
become large enough to be felt as a lump, about one billion cells. Doubling
times may be as short as 10 days or as long as several years. Four months is an
average doubling time. A cancer's doubling time is an indication of how fast it
grows. The doubling time is very important in determining the time course of the
cancer. For example, a cancer first starts when a woman is 40. It is a fast
growing cancer with a doubling time of 2 months. It takes 46 months (2x23), or
almost four years, before it is large enough to be detected by a mammogram and
60 months, or five years, before she feels it. She is diagnosed with cancer at
age 44 or 45. If, on the other hand, she has a slow growing cancer with a
doubling time of two years, she would be 86 before it could be found on a
mammogram and 100 before she could feel it. She probably would die of other
causes before she ever knew she had cancer. Carefully performed autopsy studies
show undetected invasive breast cancer in over 3% of women age 40 and older.
Since most breast cancers grow at an intermediate pace, usually the cancer has
been present for 8-10 years before being discovered. Metastatic cancer, like the
original cancer in the breast, must double in size at least 23 times before it
can be found.
http://www.imaginis.com/glossary/glossary_d.asp
Doubling time: The time it takes for a cell to divide and double itself.
The doubling time of breast cancer cells depends on many things, such as the
type of tumor, the resistance of the individual’s body, and the location in
which it tries to grow. A single cell needs 30 doublings to reach noticeable
size (1 cm) - a billion cells. Cancers vary in doubling time from 8 to 600 days,
averaging 100 to 120 days. Thus, a cancer may be present for many years before
it can be felt.