Bone Scan vs. PET scan (The official answer is: It depends.)

I’m going to ask for a PET scan requisition again. So skip this post if you don’t have time to delve into the details.

It appears that both scans come with their own set of advantages and disadvantages, and the choice often hinges on factors like the type and stage of cancer. From what I’ve gathered, bone scans (bone scintigraphy) primarily rely on detecting bone changes, particularly the bone-forming (osteoblastic) response. This response can range from normal growth and repair, to the presence of cancer which can lead to excessive and poorly formed new bone. On the other hand, a PET scan (18F-FDG-PET/CT) measures the glucose uptake (metabolic response) of cancer cells, regardless of their location.

It’s crucial to bear in mind that bone breakdown and formation are an entirely normal process. Just like other cells in our body, bones undergo continuous renewal. Think of it like skin cells, hair, nails – they all come and go. The only difference is that cancer cells have their foot firmly on the gas pedal but never crash.

Let me illustrate with an example: Both prostate cancer and breast cancer frequently metastasize to the bones. However, prostate cancer often results in bone-forming (osteoblastic) lesions. This new bone growth tends to be disorganized and structurally weak. All of that bone formation makes a bone scan an excellent choice. On the flip side, breast cancer typically leads to bone-destroying (osteolytic) lesions, which involve the breakdown of bone tissue (harder to see in a bone scan). So in that case a PET/CT would be more suitable. Of course, the choice can also depend on how the cancer responds to treatment. In my situation, for instance, if I have bone-destroying lesions and the cancer starts to recede from the bones, the bones will then begin to heal. This healing process is an osteoblastic action and will be visible on a bone scan but not on a PET scan.

There are a few studies that indicated PET would be better for Breast Cancer and some that seem to say that they were comparable. But all studies seemed to agree they were different and complimentary.

Given my current circumstances, I’m leaning towards requesting another requisition for a PET scan requisition. I am trying to cure cancer and the details are very important, I don’t want healthy bone regeneration to be confused with cancer because the bone scan can’t tell the difference. And I don’t want to keep taking DON if I don’t have to. It will be less expensive and safer to just get the best testing.