Yes, that's the risk, more side effects, and something really to consider. It may kill the cancer, but may kill you. My MO would not do chemo for three of my recurrences. On the other hand, combining several drug therapies will attack the cancer in different ways, since the chemo combined or target therapy, work differently to kill the cancer, and are not the same type, like Erbitux & Taxotere. There is hope at least one will work, if the other doesn't for some reason, and or act as a radio sensitizer. There are trials that usually show what combinations work, studies that show what doesn't work. NCCN has a listing for these for mono or combined treatments in HNC, Also, they don't combine two of same types of drugs, like Cisplatin & Carboplatinum, Taxol & Taxotere, etc. due to the toxicities. I had Induction Chemo with high dose Taxotere, Cisplatin and 5-FU..ouch! I'm still recovering 3.5 years later, so I don't recommend that. Others may have no problem.