Weekend Jitters

Scan this morning, so as usual I'm flittering between fingernail-chewing (figuratively speaking) and trying desperately to distract myself.  My misery will be relatively short-lived, as I'll be seeing Dr. Bouncy and getting a look at the scan results, if not the report, early on Monday morning.  Then we'll decide what the next treatment plan is.

I've been having some indications that all is not well, so I'm not feeling hopeful.  Starting a new treatment is rife with potential problems and risks, especially when you don't know if it will even do you any good.  

The good news is that it looks like I'm going to be able to get the CTC test done, and done within a week or so of the scan, which means we'll have some idea of a 'baseline' to work with IF the test is able to detect tumor cells in my blood.

What is a CTC test? Well, it's a special blood test that is recently available for certain cancers - breast cancer is one of them - that detects and counts the number of tumor cells circulating in your blood.  It requires specialized tubes for collection, and has to be sent to qualified labs and processed very quickly (within 48 hours). 

IF there are detectable tumor cells in your sample, the number per volume can fairly accurately predict your prognosis - at least, it can tell you whether a particular treatment is working or not, based on the tumor cell count on your last test.

The benefits:

Unlike scans, the CTC test does not irradiate you and make your cancer more likely to grow.

You can take the CTC test a month after starting a new treatment, and get some idea of whether that treatment is working.  Scans are usually limited to every 3-6 months, which can be a very long time to let a cancer grow if a treatment is not working.

CTC tests cost at 1/5th or less the cost of scans.

CTC tests don't take up as much time for the patient as a scan, and don't cause the claustrophobia or discomfort that laying still in that confining tube can bring. 

Unlike scans, CTC tests are as accurate and easy for diabetics as they are for non-diabetics.

CTC tests do not require the annoying dietary restrictions for 28 hours beforehand that scans demand.

Preliminary testing seems to indicate that when circulating tumor cells are detectable, the CTC test is more accurate in predicting likely survival time (on current treatment, at least) than scans.  I'm not completely sure about this, but I believe this is because the number of cells per volume indicates speed of metastatic spread.  And that, of course, tends to be a fairly big predictor of survival.

The disadvantages:

CTC tests do not always detect circulating tumor cells in the samples of particular people, even if they have advanced/metastatic cancer.  The circulating tumor cells that are sending metastases into distant areas of their bodies might be traveling via the spinal fluid, for instance, or the bone marrow.

CTC tests do not tell you where the tumors are, how large they are, whether they are growing, how aggressively they are growing, or if they are doing serious damage.  At best, they simply tell you if your tumors are more active, or less active, in sending out metastasizing cells.

The reason I am anxious to take this test is that the other blood tests that are indicative for breast cancer have not been effective for me - no matter how advanced my cancer gets, the results for the standard tests stay the same.  So I've been dependent on scans to tell me about whether or not a treatment is successful, and in at least one case that meant that my cancer was allowed to grow unchecked for several months, leading to a gain of nearly 20 extra tumors.  One more progression like that (or frankly, considerably less than that) will be the end of me. 

So knowing quickly whether a treatment is working could literally be a matter of life and death for me.

Wish me luck.  I need it.