victor53,
You are exactly correct in your assessment. If you have teeth that need to be extracted get them out before your chemo/rad begins.
If teeth are beyond a reasonable state of repair, have questionable bone support or have periodontal disease it would be much better to have them removed prior to chemo and/or radiation therapy. If they are left they can lead to problems that are very painful, compromise your immune system and hamper your ability to eat.
It would also be beneficial to have a very good dental cleaning and examination prior to commencing treatment.
If you have any questions please feel free to contact me.
My thoughts and prayers are with you.
Cheers,
Mike