WHY IS CANCER SPREAD SO HARD TO DETECT: BECAUSE IT IS LIKE A DANDELION

When you see a dandelion flower in the spring you know your lawn is in jeopardy. Within a month the flower will contract to produce a seed head followed by the opening up of a delicate puffball of seeds just waiting for a breeze to carry them all over your yard and your neighbors. If you attack the weed with poison or a shovel before the seed head forms you can cure the problem like an oncologist can with radiation or surgeon with a knife. A stage I dandelion or cancer is curable.

But if you get there after the dandelion has been there a while or the cancer is big, you cannot be certain of cure even if you remove everything you can see. With dandelions you can judge the chances of cure by the appearance of the puffball. If it looks full, round and symmetrical you may still have a chance with a shovel. If part of the puffball is missing you can still dig it up and temporarily produce the appearance of a victory; the rest of the lawn looks perfectly clear. However experience tells you that seedlings too small to see may be hiding in the grass and that you will need to wait for six weeks, the time it takes for a seed to germinate and produce a new dandelion, to know for sure.

That is the way it is with cancer also but the wait may be years. There is no puffball with cancer but we can get the same kind of information by looking at the size of the cancer, the characteristics of its cells and the presence or absence of cancer cells spread to nearby lymph nodes. With this data we can come up with an estimate of whether cancer cells are likely to have spread further, hidden and too small to find..

Not every dandelion seed will land in fertile soil and produce a new dandelion. Nor will every cancer seedling that jumps into the bloodstream evade the immune system or land in fertile other tissue where it can survive and grow.

We can only estimate the chances of spread. We can no more detect the individual cancer seedlings (metastasis) than a gardener crawling around searching for dandelion seedlings.. We can only find the new dandelion or cancer metastasis when it gets big enough. In the case of cancer, waiting until then can often be too late to achieve cure. Generally speaking our cancer therapies are most effective on the smallest cancers. Therefore treatment of the whole body with therapy that will kill seedlings must often be started before seedlings become big enough to see. This is called adjuvant therapy - an adjunct to surgery and if given before surgery it is called neo-adjuvant.