Final answer:
In medical terminology, 'M1' denotes the presence of metastases in cancer staging. In nuclear medicine, an 'm' next to the mass number of an isotope indicates a metastable state, not cancer metastasis. Metastasis refers to the spread of cancer cells to distant sites to form new tumors.
Step-by-step explanation:
The notation representing the presence of metastases can vary based on the context. In general medical terminology, metastasis is often documented in the staging of cancers, such as 'M1' indicating the presence of metastases. However, in the context of nuclear medicine and the identification of radioisotopes, an 'm' or '*' as a superscript next to the mass number denotes a metastable state. For example, technetium-99m, represented as Tc-99m, is a metastable isotope used in medical imaging. Here, the 'm' stands for 'metastable' and not metastasis. It's important not to confuse the metastable state of isotopes (which relates to their energy state) with the metastasis of cancer cells (which refers to their spread to distant sites).
When discussing cancer and metastasis, it is critical to note that cancer cells can spread through the bloodstream to form new cancers at distant sites, which are referred to as metastases. Different types of cancers tend to metastasize to particular organs, such as the brain, lungs, bones, and liver. The prognosis of metastatic cancer is often much worse than for cancer that has not spread.