Low NKC Function: Should I get regular cancer screenings?

I just returned from an appointment with an oncologist (Dr. L.) and wanted to share what he advised.  First, a little background is needed:

This was a follow-up appointment, scheduled 7 months ago, before I'd been diagnosed with ME/CFS.  At the time, my GP had referred me to an oncologist because I'd experienced rapid weight loss, extreme fatigue, and my blood tests showed a high white blood cell count: all signs of a possible malignancy.

But the oncologist had quickly ruled out cancer--or as close to "ruled out" as possible--based on further blood tests.  Today's appointment was scheduled as a precaution, to monitor a minor irregularity found on my CT scan.

Having since received an ME/CFS diagnosis, I almost felt that it was no longer necessary to attend today's follow-up appointment.  In fact, I very nearly cancelled.  Ultimately, I decided to go anyway, if only to ask one question that has been bothering me for months.

The question stems from my March 5th test results showing low Natural Killer Cell (NKC) function.  (8 on a scale of 8-170).  After reading a book about the immune system, I learned that NKC's have two functions: They attack viruses, and they destroy tumors before they start.  They are the immune system's primary defense against many types of cancers!  So this information, combined with the general buzz on message boards that PWME's are more susceptible to cancer, had me a little concerned.

So my question was: based on my NKC test results, should I get regular cancer screenings?

The short answer was: it depends on what you mean by "screenings."  I'll explain...

First, I should mention that Dr. L had never heard of the NKC function assay, or of low NKC function being a risk factor for cancer.  It gave me some comfort that a doctor who has devoted his life to cancer study wasn't freaking out over my test results.

But what about screenings?  According to Dr. L, existing technology is very primitive in terms of detecting cancer in its earliest stages.  There is no general "cancer test."  While there are blood tests for so-called "tumor markers," these are only useful for monitoring the treatment of a known tumor.  Tumor makers, as a screening technique, are so error prone that they've been deemed useless.  They have an unacceptably high rate of both false positives and false negatives, and therefore, doctors won't order them for diagnostic purposes.

Regular imaging, such as CT scan or X-rays are no better an option.  The problem is that the radiation builds up in your system over a lifetime.  There is currently a debate in the medical community about how often is too often for CT scans, but you'd be hard pressed to find a doctor who would recommend yearly scans as a preventative measure.  (If you're monitoring a known tumor, that's a different story.)  Due to the extra radiation, the scans might be more likely to cause cancer than to diagnose it.

According to Dr. L, the next best thing is to simply receive regular annual or bi-annual physicals, including standard blood work-ups. The blood work-up should include inflammatory markers (like sedimentation rate) which can sometimes indicate a malignancy.  All of this is, of course, in addition to following the recommended yearly PSA screenings for men, and breast cancer/pap smear screenings for women.

So, while I'm not sure that Dr. L's recommendation would be different for any normal, healthy person, I take away two things from this:  (1) piece of mind knowing that there isn't some life-saving test that I'm missing, and (2) confirmation that regular blood tests--which I'm already receiving due to my CFS treatments--are the best way to monitor my health, including possible cancers.

For those PWMEs, like me, who like to find the bright side of things, just think: the extra diagnostics we undergo for our ME/CFS may end up catching something that would have otherwise gone un-diagnosed  until it was too late!