NEW YORKA man wanted to know why his chest x-ray was normal 4
months before he was diagnosed with stage IV lung cancer. A woman
wanted to know how her mother could have negative tumor markers and
seven brain metastases at the same time.
The meaning and limitations of medical tests may confuse and even
anger patients and families. The problem came up several times during
the call-in part of a Cancer Care, Inc. teleconference on lung cancer
given by Ronald Blum, MD.
Dr. Blum, director of the Comprehensive Cancer Center and chief of
the oncology section at St. Vincents Hospital, New York, dealt with
the topic compassionately and honestly.
To the man who was diagnosed with stage IV disease and brain
metastases 4 months after a normal chest x-ray, Dr. Blum explained
that the growth rates of lung cancers, of any cancer, are
highly variable for reasons that we dont understand. The
problem is that the chest x-ray is a fairly insensitive technique.
Even the CT scan has not been proven as a useful screening device to
give us lead time to treat the disease before it spreads. So your
story is certainly one that I do hear and unfortunately is
characteristic of lung cancer.
To the daughter whose mothers blood tests failed to reveal lung
cancer metas-tases to the brain, he explained that, as yet, tumor
markers have not been established for most lung cancers. Some
lung cancers do give off proteins that are common to some other
cancers like breast cancer, colon cancer, and glandular cancer,
he said, and these proteins, although not of proven value, are
sometimes used as one of a number of methods for assessing recurrence.
To look for recurrence and progressive disease, we use the
total picture rather than a single test, he said. How
does the patient feel? Has there been any apparent weight loss? Are
there new symptoms? Are there any abnormal blood values, including
tumor markers? What about the x-rays? We use all of those.
The issue for brain metastases, he pointed out, is that the brain is
isolated. Its protected so that its not in the same
communication with the blood, and this can often be a silent area of
recurrence. Its not uncommon for the tumor marker to be
normal, he said.
Reasons for Low Hematocrit
Another lung cancer patient wondered whether the reason for her low
hematocrit could be faulty nutrition. Probably not, Dr. Blum replied.
Wouldnt it be nice if a little food would take care of
it? he said. But anemia for people with cancer is
multifactorial. The most common cause is the anemia of chronic
disease, and it has nothing to do with nutrition.
For reasons we dont understand, he said, in cancer
patients, the body doesnt make red blood cells in a normal way,
and its not because of low iron. We think its probably
due to decrease of the hormone erythropoietin. So if your count is
low, getting a transfusion or being started on Procrit (epoetin alfa)
could make an enormous difference.