Comparative Evaluation of Volumetric-Modulated Arc Therapy and Intensity-Modulated Radiotherapy in Postoperative Breast Cancer Treatment

<b>Aims/Background</b> Breast cancer (BC) is one of the most prevalent malignancies among women globally, with postoperative radiotherapy playing a pivotal role in its multidisciplinary management. Volumetric-modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) are advanced radiotherapy techniques that improve dose distribution uniformity within the target volume while minimizing damage to surrounding normal tissues. This study aimed to compare the effects of VMAT and IMRT on immune function and prognosis in postoperative BC patients, providing a scientific basis for clinical decision-making and optimizing BC treatment strategies. <b>Methods</b> Between January 2022 and January 2024, 265 postoperative BC patients who underwent radiotherapy with VMAT or IMRT at Nantong First People's Hospital were retrospectively analyzed. Based on the radiotherapy technique, patients were categorized into the VMAT group (129 cases) and the IMRT group (136 cases). The efficacies of the 2 radiotherapy techniques were compared by assessing overall radiotherapy effectiveness, levels of cancer biomarkers, levels of immune factors, quality of life and the incidence of adverse reactions. <b>Results</b> The overall objective response rate (ORR) and disease control rate (DCR) were significantly higher in the VMAT (75.97% and 93.80%, respectively) compared to the IMRT group (63.24% and 86.03%, respectively, <i>p</i> < 0.05). Serum levels of cancer antigen 15-3 (CA15-3), human epidermal growth factor receptor 2 (HER2), carcinoembryonic antigen (CEA), and interleukin-6 (IL-6) significantly decreased in both groups at 1-, 3-, and 6-month post-radiotherapy compared to levels immediately after radiotherapy (<i>p</i> < 0.05). Conversely, levels of interleukin-2 (IL-2) and interferon-α (IFN-α) demonstrated a significant increase over the same time points (<i>p</i> < 0.05). Notably, at 1-month post-radiotherapy, the VMAT group exhibited significantly lower serum levels of CA15-3, HER2, CEA, and IL-6 and significantly higher levels of IL-2 and IFN-α compared to the IMRT group (<i>p</i> < 0.05). Post-radiotherapy, quality of life (QoL) scores encompassing mental health, physical health, environmental conditions, and social relationships significantly improved in both groups compared to pre-radiotherapy levels (<i>p</i> < 0.05). However, no statistically significant differences in QoL were observed between the two groups after treatment (<i>p</i> > 0.05). The incidence of adverse reactions was significantly lower in the VMAT group (9.30%) compared to the IMRT (19.12%) group (<i>p</i> < 0.05). <b>Conclusion</b> VMAT and IMRT effectively improve cancer marker profiles, modulate immune factors, and enhance QoL in postoperative BC patients. VMAT exhibited superior efficacy, achieving higher ORR and DCR and a significant reduction in radiotherapy-related adverse reactions compared to IMRT. These findings highlight the advantages of VMAT in comprehensive BC treatment.