I’ve had one PET and four CT scans; the report from the PET Scan was very clear and was accompanied by a DVD which could be viewed on any Windows PC. I had some difficulty with the CT Scan reports, each was in a different format and used different units, one gave no measurements at all, it was very difficult to make comparisons to determine my progress. The summaries indicated that the tumour was unchanged in size. I was informed that following the WHO standards any reduction of less than 30% or a growth of less than 20% is considered to be “no change”. This concerned me because it indicated that my tumour could have either increased by 19.9% or reduced by 29.9%, a range of almost 50% based on the original size. I know that there are wide tolerances on the CT Scanners but I thought they could do better than this. I couldn’t even get reports in the same format and units; it seemed to depend upon the whim and fancy of the doctor on duty at the time. Honestly I’ve had more professional reports from my garage or pest control firm.
After making a few enquiries I was very fortunate in finding a well organised and very professional imaging practice that was willing to carry out an independent review of my CT Scans. The thing I’m most interested in is a comparison from the beginning to the most recent, at last I have some numbers, just wish I understood exactly what they mean but the summary is good and says “there does appear to have been a slight decrease in size between the initial scans and the current study” The initial dimensions were 26 x 37 x 40mm (AP x ML x CC) and in the same order the latest scan they are 18 x 34 x 36mm.
The Imaging firm that I will be going to in future uses a European Reporting Standard version RECIST 1.1 (Response Evaluation Criteria In Solid Tumours), this is considered to be a voluntary replacement for the WHO & UICC criteria which was first issued in 1979, Recist is now used by the majority of clinical trials units worldwide. Some tumours are really a very sloppy bag of gunk that easily changes shape depending upon the position of the patient, the pressure in the lungs, temperature and many other factors making it near impossible to obtain a measure of the volume. The new standard recommends a comparison based only on individual measurements rather than area or volume.
In my case the individual reductions for each dimension in my case are 30.76%, 8.10% and 10.00% but this is a comparison from first diagnosis to the most recent CT Scan.
The conclusion of each report is usually based only on the current and the previous CT Scan and then a decrease of less than 30% or an increase of less than 20% are regarded as being “No Change”, this is to allow for the scanner tolerances and other errors in the measurements. It concerns me that a range of nearly 50% can result in the same conclusion. In future I will be looking at the measurements in millimetres. In my case, comparing the initial diagnosis to my latest scan the reductions in the individual measurements are 30.76%, 8.1% and 10%. The volume is not considered reliable enough to use for comparison purposes but it would be a decrease of 42.47% in the size of the tumour.
I have since been advised of the following dimension descriptions:
AP – Anterior Posterior or front to back
ML – Medial Lateral or from centre to side
CC – Cranial Caudal or from top to bottom
The Imaging firm that I will be using in future (PRP), has the latest equipment with automated measurements. Once I have had two scans from them I should have a far more reliable measure of my progress.
