Tag Archives: how response is measured in lung cancer

Playing the numbers

Slow, but steady. The results are in from my recent CT scan and 40% resolution has eased on up to 45%. A significant five percent, as the negative side effects (gastrointestinal issues) from LDK378 have increased in intensity as well.  Dr. Shaw and I had spoken about possibly moving my dose back down to 400 mg if there had been no incremental improvement in tumor burden.

The Radiology Report is less cheering, although certainly is not what I would characterize as a bad report. It reads:

IMPRESSION:  Persistent groundglass opacities in the anterior and inferior left lung and along the right minor fissure. The opacities in the left lung are slightly more prominent. There are no definite new lesions.

It’s all a curious algorithm; this response/non-response thing. “Tumor size has traditionally been estimated from bidimensional measurements (the product of the longest diameter and its longest perpendicular diameter for each tumor)” (quoted from an article in the Japanese Journal of Clinical Oncology) Basically, a linear measurement, which is quite dependent upon the outside diameter of a lesion, is used to estimate volume. Baseline measurements are taken at the onset of a particular treatment, and response (and/or stability or progression) is assessed by comparing successive scans to the initial chest CT. Evidently my earlier 40% (https://lifeandbreath.wordpress.com/2011/12/14/big-four-oh/) was not the cutoff for partial response but rather exceeded it. I should have done my homework. From Wikipedia:

Evaluation of target lesions

  • Complete Response (CR): Disappearance of all target lesions
  • Partial Response (PR): At least a 30% decrease in the sum of the LD of target lesions, taking as reference the baseline sum LD
  • Stable Disease (SD): Neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD, taking as reference the smallest sum LD since the treatment started
  • Progressive Disease (PD): At least a 20% increase in the sum of the LD of target lesions, taking as reference the smallest sum LD recorded since the treatment started or the appearance of one or more new lesion

Odd as well is the 5% increase in response coupled with the possible area of greater consolidation noted on the radiology report. Which to me illustrates the limitations of any sort of quantitative measurements; it is all seems a bit hypothetical/ best guess sort of stuff. Data collection. Bottom line, my lungs feel and sound pretty darn good.

The numbers on my labs are closer to normal as well; the oral iron supplement I began taking several weeks ago is helping.

The one concern of the moment is my liver enzymes, transaminases-SGOT and SGPT.

So what is a transaminase? From MedicineNet.com: The transaminases are enzymes that catalyze chemical reactions in the body in which an amino group is transferred from a donor molecule to a recipient molecule. (!)

SGOT is an acronym for serum glutamic oxaloacetic transaminase and SGPT for serum glutamic pyruvic transaminase. Just in case you wanted to know. What is really relevant is that they are enzymes in the liver and elevated values of either can be an indicator of liver inflammation.

My SGOT/SGPT values were ever so slightly elevated the entire time I was on crizotinib. When I went off treatment they fell to normal levels, but soon after my first dose of LDK378, the levels again became slightly elevated. After my dose went up to 500 mg, the values began to rise again.  My SGOT level peaked at 84 a week ago and is now down to 67. The normal reference range for SGOT is 9-32 U/L  (units per liter of serum–the liquid part of blood). My SGPT was at 79 last week and this week  topped out at 102. Normal reference ranges for SGPT are 7-30 U/L.

Hopefully the SGPT has peaked and will start to go down. In the meantime, a glass of wine in the evening is not an option. Sadly, we’ve been invited to a wine tasting party this very weekend (for the oenophiles out there, all with a rating of 93 or above). When I asked Alice (Dr Shaw) if I’d be able to participate, she said, “Wine tasting is just sips of wine, right?” “Well…” I replied, “it can be done that way”.  So I’ve been given clearance to slosh a bit around in my mouth. Just like the real sommeliers. I don’t believe I’ll be able to bring myself to spit it out though; that just wouldn’t be right.