I know a little about parathyroid cancer.

Firstly it is generally not staged. It's usually classified as localized or metastatic.

The primary treatment is surgical removal. Even if it has spread to other areas of the body. The intent with the treatment is curative.

Unlike other cancers, if it spreads say for example to the lungs, they will still go in and remove the tumor This is because it is such a slow growing cancer that it is usually still localized to where it has grown and has not seeded beyond the surrounding tissues.

Often they will follow up with radiation (a seed, pill, or possibly external) there is a high incidence of recurrence, but again because it is such a slow growing cancer its often simply excised or another dose of radiation is given. Generally if it does spread the first place it moves to is the nodes.

tell your friend best of luck. He will have to be on calcium - for life, and will have to watch his levels. hugs.