Radiation = non-measurable disease? - 1254168

Mon, 02/25/2013 - 05:17

Hi,

My mother (Stage IV, NSCLC adenocarcinoma, mets to ribs and pleural effusion) recently underwent radiation to the primary tumour and mediastinal lymph nodes. We went to see an oncologist for a second opinion, and he was talking about her eligibility for a clinical trial, noting that because she had radiation, there may not be measurable disease. My question is why does an irradiated tumour become non-measurable?

Also, another oncologist commented that because she had radiation, that it may make her scans hard to read - just wondering why that might be?

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certain spring

Hallo neverenough. I am not a doctor but can help with some explanation here as I too have scans that are hard to read and a tumour that is "non-measurable".
As it destroys the cancer, radiation creates a lot of scar tissue and general debris. This shows up as white and cloudy on the scans. This cloud effect tends to obscure the clearly defined borders of organs (say the heart) or objects (like a tumour). Without a clear border it is harder to measure whether something is growing or shrinking, although there are other ways of understanding what is going on.
However, I am not sure whether, without seeing your mother's scans, your second-opinion oncologist can predict that her scans will be hard to read - that will depend on how much radiation your mother has had, where and how recently. Also, please don't be discouraged as some clinical trials accept people with disease that is non-measurable. Best to you and your mother.

catdander

Hi neverenough, I'm very sorry that your mother is in such a situation. Certain spring has covered all the bases. I've pasted a discussion about radiation and scanning below. The topic of pancoast tumor makes it a little different than your situation but the discussion about radiation causing difficulty in reading scans is very informative.

http://cancergrace.org/lung/2010/05/26/imaging-after-chemor/

Janine
forum moderator

Dr West

certain spring has really described the situation very well. Radiated lesions are often subsequently visible as a combination of dead cancer, dying cancer, inflammatory change, scarring, and possibly some viable cancer as well -- but we can't really know how much of which elements are present. Because of that, any radiated lesion is considered non-measurable for the purposes of a clinical trial. There would need to be visible, measurable disease (not a bone lesion or pleural effusion, for instance, which are considered non-measurable evidence of the disease state, more of a yes/no) to follow for assessing a response to treatment on the clinical trial.

Good luck.

-Dr. West

Dr West

The answer to your either/or question is really "yes"...they can do either. We follow the scans over time, and if they don't grow or increase in number, we're pretty happy, because you don't have to have normal-appearing scans, just no evidence of viable, progressing cancer.

-Dr. West