PET Scan Results

On Friday April 8^th 2011 I had a full body PET scan as per the requirements for the SGN-35 clinical trial.  The scan itself was straightforward and uneventful.  About an hour before the scan I was injected with the FDG tracer (radioactive glucose analog that the cancer cells will consume causing them to appear on the scan).  After injection I was not allowed to move around or do anything repetitive including reading or chewing gum as it would cause uptake of the tracer into the area being used so I sat and listened to tunes on my phone and took a short nap. Once my hour was up I spent 15 minutes being scanned on a machine that looked exactly like a normal CT scan machine then was free to go with instructions to avoid children and pregnant women for 12 hours (due to the radiation). 

PET scans measure the degree of metabolic activity by standardized uptake value (SUV).  High SUV indicates high metabolic activity and potentially aggressive disease.  Uptake of the tracer does not necessarily indicate malignancy; inflammation will also cause uptake and organs will consume the tracer.  For post HL treatment scans generally lymph node activity greater than 2.5 is a concern.  One study of the efficacy of PET scans indicated a mean SUV of 7.3 for newly diagnosed HL patients.

PET Scan Report:

Indication

Lymphoma Screening for clinical trial

Technique

438MBq of FGD was administered intravenously following a six-hour fast and informed consent.  Prior to injection, the blood glucose level was 5.3.  Approximately one hour later, low mA non-contrast CT and co-registered emission PET images were acquired of the total body.  Comparison was done with a previous CT abdomen and pelvis dated March 4. 2011.

Findings

There is extensive bilateral mostly lower posterior cervical lymphadenopathy seen (moreso on the right) which is intensely FDG avid, with a maximum update SUV 9.2.  Extensive bilateral surpa and infraclavicular, axillary, mediastinal and bilateral hilar lymphadenopathy is also seen with intense FDG update [SUV max 8.8].  Multiple pulmonary nodules are seen with focally increased FDG uptake [SUB max 5.8] likely representing pulmonary involvement.  Pericardial effusion is seen with no pleural effusion.

Splenomegaly is seen with 3 focal moderate to intense FDG-avid lesions [SUV max 6.8].  Multiple retroperitoneal, celiac, gastrohepatic and lower para-aortic FGD-avid lymph nodes are seen with intense FGD activity [SUV max 8.6].  No other focal FDG avid abdominal or pelvic lesion is seen.  Mild diffuse activity in the right psoas muscle.  No definite focal FDG avid osseous lesion is seen but there is mild diffuse accentuation of bone marrow activity and bone marrow involvement may be present.

Impression

Extensive widespread intensely FGD avid lymphadenopathy, with splenomegaly and multifocal spleen lesions, pulmonary lesions and possible bone marrow involvement. 

My Translation (written specially for you Rez):

There is extensive enlargement of the lymph nodes on both sides of the neck (moreso on the right) with a maximum uptake value of 9.2.  Extensive enlargement of the lymph nodes on both sides of the chest with a maximum uptake value of 8.8 (see image below for specific locations).  Multiple collections of cells are seen in the lung with maximum uptake value of 5.8, likely representing lung involvement.  Excess fluid surrounds the pericardium (sack that contains the heart and the roots of the great vessels.) with no fluid around the lungs (a previous CT showed a pleural effusion but it went away when I was on Dexamethasone in late February after having my wisdom teeth removed). 

Enlargement of the spleen is seen with three moderate to intense lesions with a maximum uptake value of 6.8.  Multiple abdominal cavity lymph nodes are seen with a maximum uptake value of 8.6 (see image below for specific locations).   Mild diffuse activity in a right pelvis muscle.  No definite bone lesion is seen but there is mild scattered increased bone marrow activity indicating possible bone marrow involvement (bone marrow biopsy performed February 15^th 2011 showed no bone marrow involvement).

The PET results indicate there may be bone marrow involvement although the previous BMB was negative.  Given that the BMB was done almost 8 weeks ago it is possible that bone marrow involvement started after the biopsy.   In addition it is possible for BMB’s to produce false negatives.  I have not spoken with Doc Restrepo about this yet but I don’t expect them to perform another BMB to find out since the results would not change the treatment plan.  Bone marrow involvement is not considered an adverse prognostic factor.

Treatment (6 cycles of ABVD + SGN-35) will start on April 19th at 0900.

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