Among any groups of patients given the same radiation treatment, some show more sever normal-tissue reactions than others, and a small proportion suffer unacceptable late sequelae.
What is sequelae? Well it is apparently bad and can potentially result from radiation treatment. I decided to try my handy new Dorland's Illustrated Medical Dictionary, Twenty-fifth Edition and looked up the word:
sequelae plural of sequela
Had I taken Latin I suppose I could have seen that coming.
sequela any lesion or affection following or caused by an attack of disease.
Only slightly more helpful, I suppose - "any affection"? I went to wikipedia to understand better and got
a pathological condition resulting from a disease, injury, or other trauma.
Ah! Much better! Just in case it isn't clear yet, let me translate. A sequelae is something (usually known as a symptom or bad shit) that occurs because of something medical happening. If I was writing the textbook, (maybe I can volunteer for the 7th edition) the original paragraph could have read:
Among any groups of patients given the same radiation treatment, some show more sever normal-tissue reactions than others, and a small proportion suffer from some bad shit so they refuse treatment .