These stories are horrifying. While I believe they don't represent the majority of all RT procedures which have measurable successes, considering individual circumstances, this does happen. Sometimes, you know of someone that has had a bad experience...
A very good friend of mine passed away due to (metastasis of) squamous cell carcinoma in his left sinus cavity...not too long ago.
For him, it started out as a consistently stuffed up sinus. After some time, and I think it may have been too advanced by this time, the cancer was diagnosed. He underwent extensive RT treatment. They had to graft skin from his left arm to cover the damaged skin on the left side of his face. The RT was so aggressive that the bone mass around his left eye was softened and damaged, they had to remove his left eye. Subsequently, he lost all his teeth, had little salivary action and couldn't even eat properly. He suffered a great deal until his death. They suspect the initial treatments were mis-calibrated and delivered improperly. Not a great statement for his widow, children and grandchildren to hear.
We had known each other very well since we were 15. He stood up with me at my wedding.