What type of cancer is "initially not-covered" as per the text?

The choice of leukemia as the cancer that is "initially not-covered" likely stems from specific medical guidelines or policies regarding initial imaging studies for certain types of cancers. In clinical practice, leukemia is often diagnosed through blood tests and bone marrow examinations rather than imaging techniques. As such, initial imaging studies, which might include PET scans, are not routinely performed for leukemia due to the lack of direct visual indicators in the same way that solid tumors might present.

In contrast, other cancers such as breast cancer, prostate cancer, and thyroid cancer typically involve more established protocols for imaging in their initial evaluation and diagnosis, including the use of PET scans or similar methodologies. These imaging procedures are used to assess tumor presence, stage the disease, or monitor response to therapy, making them more frequently covered as part of standard care.

Therefore, leukemia’s nature as a hematologic malignancy and its reliance on different diagnostic approaches helps clarify why it would be categorized as "initially not-covered" for imaging studies like those performed in PET.