CEA Surge in Metastatic Colorectal Cancer Patients Responding to Oxaliplatin

[Guest guest]

Interesting letter from a doctor to the Journal of Clinical Oncology

published last month. He gave successful Oxaliplatin therapy to a

series of 27 patients....and their CEA went UP rather than down!

Journal of Clinical Oncology, Vol 21, Issue 23 (December), 2003: 4466-

4467

I posted it over on the " Experimental " Board (which I use for the

more " technical " articles. Here is a link:

http://tinyurl.com/3gayz

This doctor says 4 of his 27 patients experienced a " Median rise in

CEA from baseline of 263% (range, 24% to 632%) " , while at the same

time their tumors were STABLE OR SHRINKING!!!

He goes on to say:

[snip]

In this study we found a clinically relevant CEA surge in four of 27

patients on therapy. We believe this new observation may be due to

the introduction of a more effective chemotherapy regimen for

metastatic colorectal cancer. Oxaliplatin based chemotherapy is more

effective giving a doubling of response rate compared with FU

regimens alone.1 A transient increase in tumor markers after

chemotherapy has previously been seen in responding patients with

nonseminomatous testicular cancer and breast cancer.2–3 In six of

the breast cancer patients, the initial CEA surge was incorrectly

interpreted as evidence of disease progression, and inappropriate

therapy changes were made.3 The most common pattern of tumor marker

response after initiation of chemotherapy in responding patients is

regression towards normal levels. A consistent rise in CEA is

generally thought to be indicative of disease progression. An early

rise in tumor markers after treatment start should, however, be

serially followed to differentiate a true from a transient rise.

So...just goes to show you how DIFFICULT CEA can be to interpret!

Not only may CEA rise due to disease progression...it can also rise

due to therapy WORKING TOO WELL!

Author notes that going " by the book " , these successful patients

would have had their therapy INCORRECTLY DISCONTINUED!!!

[sNIP]

If we had followed this ASCO guideline of measurement of CEA level

every second month, one of the surge patients would have been

incorrectly interpreted as having experienced treatment failure, and

therapy would have stopped. The patient would have been incorrectly

removed from the treatment, giving her a time to progression of 11.2

months and 27.3-month survival. To avoid inappropriate therapy

changes based on clinical misinterpretation of a CEA surge as an

impending disease progression, we suggest that future ASCO guidelines

should mention the possibility of CEA surge. Furthermore, we suggest

that no therapy changes should be based on CEA levels alone at all

during the first 6 months of therapy.

Something to think about when considering the implications of CEA!

Pretty interesting, no?

Best Wishes,