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Advances in Radiotherapy
& Nuclear Medicine Brachytherapy versus external beam in local dose escalation

capacity to generate precise dose distributions without median patient age, and clinical endpoints across all
requiring additional margins for setup uncertainties or included tumor sites.
organ motion, as the source remains fixed relative to the
tumor during treatment. In contrast, EBRT necessitates 2.2. Information sources and search strategy
expanded planning target volumes (PTVs) to account for This systematic review was conducted in accordance with
such variations. 3,5 the Preferred Reporting Items for Systematic Reviews and
8
By optimizing the dose differential between the tumor Meta-Analyses guidelines. A comprehensive literature
and surrounding healthy structures, IRT significantly search was performed in PubMed, Scopus, and Web of
reduces unnecessary radiation exposure to non-target Science for articles published up to December 2024. The
tissues. Moreover, treatment can typically be completed in a review focused on full-text studies assessing the clinical
shorter timeframe compared to the extended fractionation impact of an IRT boost compared to an EBRT boost in
schedules of EBRT. This reduced overall treatment patients with breast, prostate, endometrial, cervical, head-
duration is particularly advantageous for tumors with high and-neck, and anal cancers.
proliferative potential, as it may enhance local control (LC) The search strategy utilized a combination of Medical
by limiting opportunities for tumor repopulation. 6,7 Subject Headings and relevant keywords, including:
Dosimetric analyses have consistently demonstrated “breast neoplasms,” “prostate neoplasms,” “endometrial
that IRT is highly effective in delivering ablative doses to neoplasms,” “cervix neoplasms,” “head-and-neck
tumors while preserving the integrity of nearby organs at neoplasms,” “anal cancer neoplasms,” “radiotherapy,”
risk (OARs). It can be employed either as monotherapy “brachytherapy,” and “toxicity.” The complete MEDLINE
or in combination with EBRT to enable localized dose search strategy is provided in Tables 1-6.
escalation, particularly in the management of advanced The search was limited to articles published in English
primary tumors such as those of the cervix and prostate. 2-6 between 1990 and 2024. Only clinical studies evaluating

The objective of this systematic review is to assess the patients treated with either an IRT or EBRT boost
clinical efficacy of an IRT boost compared to an EBRT boost following ERBT were considered. Non-original research
in patients with breast, prostate, endometrial, cervical, formats such as conference abstracts, surveys, editorials,
head-and-neck, and anal cancers. Key outcomes include letters, book chapters, and narrative or systematic reviews
LC, cancer-specific survival (CSS), overall survival (OS), were excluded.
distant metastasis-free survival (DMFS), and treatment- 2.3. Selection process
related toxicity.
Two independent reviewers (MCLM and NB) screened
2. Materials and methods titles and abstracts to identify eligible studies for inclusion.

2.1. Eligibility criteria In cases of uncertainty regarding study eligibility, a
multidisciplinary and multicenter expert panel (GK, VL)
The clinical question guiding this systematic review was was consulted to reach consensus. Final verification and
structured according to the PICO framework as follows: approval of the included studies were conducted by an
(i) Population (P): Studies included randomized independent review committee (MAG, LT).
controlled trials as well as prospective, retrospective,
and cohort studies involving adult patients (aged 2.4. Data collection process
≥18 years) with primary cancer who received a A standardized data extraction form was developed and
radiation boost with IRT as part of their treatment utilized by two independent reviewers (MCLM and NB) to
(ii) Intervention (I): Radiotherapy protocols incorporating extract relevant data from the included studies. Extracted
an IRT boost were considered the intervention of data were cross-checked, and any discrepancies were
interest resolved through discussion and consensus.
(iii) Comparison (C): The comparator group consisted
of patients who received radiotherapy followed by a 2.5. Data items
boost with EBRT The primary outcome was LC, defined as the time
(iv) Outcomes (O): The primary outcome was LC. interval from the initiation of the IRT or EBRT boost to
Secondary outcomes included CSS, OS, DMFS, and the occurrence of in-field relapse, disease progression
the incidence of treatment-related adverse events. or persistence, or the date of last follow-up, whichever
A summary table was developed to report study occurred first. Secondary outcomes included CSS, OS,
characteristics, including study design, sample size, DMFS, and adverse event rates. CSS was defined as the

Volume 3 Issue 3 (2025) 15 doi: 10.36922/ARNM025160017