- Overlap of radiotherapy with minimum 2 cycles of platinum-based chemotherapy (one cycle is defined as either 3 or 4 weeks depending on the chemotherapy regimen). A deviation of 2 to 3 days from an exact overlap is acceptable. Purely radiosensitizing doses of chemotherapy are not acceptable (for example [e.g.], daily low dose regimens; weekly carbo-platinum + paclitaxel regimens are allowed).