Help understanding scan results?

Hi all,
After 1.5 years of first-line Keytruda treatment, they've stopped treatment and are now doing watch and wait.

Here are the results of the first post-Keytruda scan. The doc is simply calling these results "stable." He's a man of few words, at least when talking to patients!  So…I ask you. How bad/good are these results? What if anything should I be concerned about? Brain? Bones? Prostate?

Study Result

Impression
IMPRESSION:

1. Grossly stable to minimally increased size/FDG activity associated with a hypermetabolic soft tissue nodule dorsal to the C7/T1 spinous processes. Other findings, as described.

2. Unchanged multifocal FDG uptake within the prostate gland compared with 3/2018 and more prominent than in 1/2017, as described.

Narrative

WHOLE-BODY F18-FDG PET-CT: 6/5/2018 8:20

CLINICAL HISTORY: History of melanoma, referred for evaluation of whole-body. This PET/CT scan is requested for follow-up.

PET SEQUENCE: Subsequent treatment strategy

COMPARISON: PET/CT, 3/9/2018 and 1/2017.

PROCEDURE COMMENTS:
Tracer information:
Measured (injected) dose: 11.5 mCi.
Injection site: Left antecubital fossa.
Anatomical region: The area imaged included the vertex to toes
Lasix: None.
Oral contrast: None.
IV contrast: None.

Scan technique: Following IV administration of the radiopharmaceutical, images were acquired using a MI PET-CT scanner. A low-dose CT scan was performed for attenuation correction and anatomic correlation only. If a comprehensive diagnostic CT is required, the Department of Radiology should be consulted for an adjunct CT study. Images were reconstructed using OSEM, and both OSEM and BSREM algorithms when studies were acquired on scanner models MI and 710. On these scanners, future reconstruction will only be with BSREM. CTAC dose information: Based on a 32 cm phantom, the estimated radiation dose (CTDIvol [mGy]) for each series in this exam is 2.18. The estimated cumulative dose (DLP [mGy-cm]) is 318.21.

Images were reviewed in the axial, coronal, and sagittal planes. For descriptive purposes, the maximum standard uptake value (SUV max) of metabolically active tissues is reported in g/mL, unless stated otherwise. The image number corresponding to the CT series is provided in reference to findings.

FINDINGS:

Head/Neck:
Brain: Limited evaluation of the brain demonstrates intense symmetric FDG uptake in the visualized cerebral cortex gray matter. This high physiologic background activity reduces the sensitivity of FDG-PET for malignant processes. There is somewhat more prominent focal activity in the sella, possibly physiologic versus treatment related.
Paranasal sinuses: Clear.
Lymph Nodes: No enlarged or hypermetabolic cervical lymph nodes.
Tongue/Tonsillar tissues: Physiologic oropharyngeal uptake is seen.
Thyroid: No FDG avid lesions.

Slight increased size/FDG activity of soft tissue nodule dorsal to the C7/71 spinaeous processes to the left of the midline (CT image 58). This nodule now measures ~1.4 x 1 cm with SUV of 6, previously ~1.2 x 1 cm with SUV of 5.3.

Chest:
Lymph nodes: No FDG-avid or enlarged supraclavicular, mediastinal, hilar, or axillary adenopathy.
Lungs: No FDG-avid pulmonary lesions. Lung parenchymal evaluation, including for punctate nodules, is limited by low dose CT and non-breathhold technique. Slightly more prominent ~0.2 cm subpleural nodule on the superior segment of the LLL on image 76 is too small for PET characterization and non-specific.
Pleura: No pleural effusions or hypermetabolic lesions. Stable redemonstration of mild left medial posterior pleural nodularity without significant FDG uptake remains non-specific on image 81.
Chest Wall: No FDG-avid lesion.
Heart: Atherosclerotic calcification of the coronary arteries is present. No pericardial effusion.
Other Findings: None.

Abdomen/Pelvis:
Liver: No FDG-avid liver lesion.
Gallbladder: Normal.
Spleen: Normal in size and metabolic activity.
Pancreas: No FDG-avid lesion.
Adrenals: No FDG-avid lesion.
Bowel: Physiologic FDG uptake is seen in the bowel. No focally FDG-avid lesion.
Kidneys/Bladder: Normal physiologic excretion of the radiopharmaceutical. No FDG-avid lesions.
Ascites: None.
Lymph Nodes: No FDG-avid or enlarged abdominal, retroperitoneal or pelvic adenopathy.
Vasculature: Normal abdominal aortic diameter (<3cm).
Other Findings: Again seen is multifocal FDG uptake within the prostate gland (seems more prominent than on 1/2017), possibly due to inflammatory/infectious etiology though malignancy is not excluded with PET. Recommend correlation with clinical evaluation.

Musculoskeletal:
Bones: MIld focal FDG uptake within lucent subcentimeter focus on the left aspect of likely C5 vertebral body is grossly unchanged or slightly decreased in size from prior measuring ~0.5 cm with SUV of 2.3. This lesion measured ~0.3 cm in outside scan of 1/2017 -and maybe reflects overall stability but difference in technique. Continue attention. Multiple sclerotic lesions in the bilateral iliac bones, without associated abnormal FDG avidity, similar to prior.

Other Findings: No obvious focal or abnormal FDG uptake within skin/subcutaneous posterior to medial aspect of right scapula.