Local radiation dose escalation in cancer treatment: Interventional radiotherapy versus modern external beam techniques

Interventional radiotherapy (IRT), also known as brachytherapy, is an advanced radiotherapeutic modality characterized by the precise placement of radioactive sources within or near the tumor. This approach enables the delivery of high radiation doses directly to the tumor site while minimizing exposure to surrounding healthy tissues. IRT is indicated for various malignancies and is integrated into both definitive and multimodal oncologic treatment strategies. Referral to IRT, as well as its implementation, often involves a multidisciplinary team including specialists from radiation oncology, surgical oncology, and medical oncology. To enhance oncological outcomes, numerous studies have investigated the incorporation of a radiotherapy boost–either IRT or external beam radiotherapy (EBRT)–targeting residual tumor following exclusive radio-chemotherapy. The decision to use an IRT boost versus an EBRT boost remains a topic of discussion and frequently depends on the equipment available at cancer centers. This systematic review aims to evaluate the comparative effectiveness of an IRT boost versus an EBRT boost in patients with breast, prostate, endometrial, cervical, head-and-neck, and anal cancers. Outcomes of interest include local control, cancer-specific survival, overall survival, distant metastasis-free survival, and treatment-related toxicity. Taking into and account, the proven clinical and economical advantages of a high-workload IRT center, education in IRT and multidisciplinary cooperation of different specialties should be forced.