Which of the following is an indicator of higher FDG uptake in certain cancers?

Higher FDG uptake in cancers is often associated with metastatic spread. This is primarily due to the increased metabolic activity characteristic of cancer cells, especially in advanced stages. When a tumor metastasizes, it typically exhibits not only higher rates of glucose metabolism but also a more aggressive biological behavior, necessitating more energy, which is reflected in an elevated uptake of FDG (fluorodeoxyglucose) during PET imaging.

The metabolic processes in metastatic cells are often significantly enhanced compared to localized tumors, which may not show the same level of activity, particularly if they are smaller or less aggressive. Metastatic cancer typically involves more proliferative activity, leading to increased FDG uptake as these cells preferentially utilize glucose for their energy needs.

Understanding this distinction helps in better interpreting PET scans and assessing the progression or severity of cancer. In contrast, localized tumors and other conditions like necrotic tissue or inflammatory responses may not show the same level of uptake, as their metabolic demands can differ significantly from those of metastatic disease.