The therapeutic window can be increased by:Fractionation of the total doseDecreasing the toxicity → lower the dose to normal tissueIncreasing the tumor control → enhancing the sensitivityThe sensitivity can be enhanced via:ChemoradiotherapyRadiotherapy + chemotherapyBiological agentsCetuximab in head and neck cancerOxygen to tumor tissueIncreases the oxygen which reaches the tumor → high response rateDoesn’t really workHyperthermiaExposing tumor tissue to high temperaturesIn patients with cervical cancer and relapses of breast cancer Chemoradiation is a combination between radiotherapy and chemotherapy. This can be:Concomitant: in the same time periodSequential: behind each other If chemoradiation is used, DNA damage to tumor cells is more often fatal than with irradiation alone. Normal cells have a greater variety of escape mechanisms and repair the damage, which causes them to be more able to repair DNA than tumor cells → have a higher tolerance to the therapy. There are different modes of action for radiation and chemotherapy. Chemotherapy is used as a radiosensitizer which enhances the effect of radiotherapy. Chemo- and radiotherapy can be used to create synergy:Cisplatin adducts to DNA → causes single strand breaksRadiotherapy will create more breaks which are more difficult to repairPost-irradiation repair is inhibitedChemotherapy inhibits nucleotide metabolism, while radiation is effective in a different phase of the cell. Chemotherapy treats hypoxic cells, which are less radiosensitive for radiotherapy. Chemoradiation is seen as local treatment to increase local control and thereby cure. Chemoradiation is only used in curative treatment:As a primary treatment modalityOrgan saving treatmentCurative resection is not...