Abstract Objective: Breast cancer is the most common malignancy among women worldwide, including Morocco. Radiotherapy plays a key role after surgery by eliminating residual disease and reducing local recurrence. This study compares the dosimetric and biological performance of intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) for breast cancer treatment using the Halcyon linear accelerator. Methods: IMRT and VMAT treatment plans were retrospectively compared in 25 breast cancer patients. Dosimetric evaluation was performed using dose–volume histograms for the planning target volume and organs at risk. Biological assessment included normal tissue complication probability (NTCP), secondary cancer complication probability (SCCP), and tumour control probability (TCP) calculated with established predictive models. Results: Both techniques achieved comparable target coverage (V95%), with a slight advantage for VMAT. VMAT showed improved dose homogeneity and conformity, while IMRT required higher monitor units. IMRT provided superior sparing of organs at risk, particularly the lungs, heart, and contralateral breast. NTCP and SCCP estimates were lower with IMRT, suggesting reduced risks of radiation pneumonitis and secondary malignancies. TCP was marginally higher with VMAT, without statistical significance. Conclusion: IMRT offers better protection of healthy tissues, whereas VMAT improves target dosimetric quality and treatment efficiency.
Abour et al. (2026) studied this question.