In photon radiotherapy, Simultaneous integrated boost (SIB)-intensity-modulated radiation therapy (IMRT) with slight hypofractionation in the HR-CTV is the current standard of care, being previously largely adopted in clinical practice and within several prospective clinical trials, with similar results in terms of toxicity and oncologic outcome.~Up to now, a simultaneous integrated boost (SIB) approach has not been fully exploited in CIRT so far. The expected benefit of a SIB planning approach in carbon ion treatment is the reduction of toxicity with respect to the sequential (SEQ) approach currently used in CNAO clinical practice, while maintaining the same local control rate. This benefit depends on the potentiality of SIB to better spare normal tissues, further enhancing the intrinsic favourable physical and radiobiological characteristics of the carbon ions.
The investigators aim at investigating in a prospective clinical trial whether using a Simoultaneous Integrated Boost of carbon ions treatment planning approach, improving the tumor dose conformation while lowering the unintended dose to the low-risk volume, can significantly reduce the probability of toxicity without affecting Local Control.