Breast cancer is a highly prevalent malignancy originating from breast tissue, affecting individuals of all genders but disproportionately impacting women. Early detection through routine screening, such as mammography, is critical for improving treatment outcomes. Standard treatment modalities include surgery, chemotherapy, hormone therapy, and radiotherapy. Radiotherapy plays a vital role in breast cancer management, particularly following breast-conserving surgery. It utilizes high-energy X-rays or other radiation modalities to destroy cancer cells and reduce the risk of recurrence. Among modern techniques, hypofractionated radiotherapy delivers higher doses per fraction over fewer treatment sessions. This approach improves treatment efficiency and convenience while minimizing toxicity to surrounding healthy tissue. Clinical trials have demonstrated that hypofractionated schedules provide equivalent tumor control and improved quality of life in early-stage breast cancer patients [1] - [3] .

Three-Dimensional Conformal Radiotherapy (3DCRT) is a widely accepted treatment for breast cancer. This technique uses imaging technologies to create a three-dimensional representation of the tumor and nearby structures, allowing precise radiation delivery and reduced exposure to adjacent organs at risk (OARs). Despite its advantages, 3DCRT poses several challenges:

Overcoming these barriers requires robust quality assurance, individualized planning strategies, and resource-adapted protocols to ensure safe and effective treatment.

Radiation-induced cardiotoxicity (RIC) remains a major concern, particularly for patients with left-sided breast cancer due to the heart’s anatomical proximity to the treatment field. Although 3DCRT effectively targets malignant tissue, unintended radiation exposure to cardiac structures can lead to acute and long-term cardiovascular complications, including:

The risk and severity of cardiotoxicity correlate with total radiation dose, fraction size, and the volume of the heart exposed [6] [7] . A pivotal study by Darby et al. demonstrated a linear increase in the risk of ischemic heart disease with each Gray (Gy) of mean heart dose delivered [7] .

To address this risk, several cardiac-sparing techniques have been developed:

Incorporating heart dose constraints into treatment planning, such as maintaining mean heart dose below 5 Gy or limiting V25Gy, is essential for minimizing cardiotoxicity while preserving effective tumor control.

This retrospective study was conducted at a single cancer center in Bangladesh and evaluated female breast cancer patients treated with hypofractionated three-dimensional conformal radiotherapy (3DCRT). The primary objective was to assess target volume coverage and radiation exposure to organs-at-risk (OARs), with particular focus on the heart and lungs. Dosimetric data were collected from treatment planning records and analyzed using the Monaco Treatment Planning System (TPS) by Elekta.

A total of 20 female patients diagnosed with unilateral breast cancer were included. All patients underwent breast-conserving surgery followed by adjuvant hypofractionated 3DCRT. Both right- and left-sided cases were included in the study cohort. Exclusion criteria consisted of a history of prior cardiac disease, prior thoracic radiotherapy, or metastatic disease at diagnosis.

Patients were simulated in a supine position with both arms raised and immobilized using a breast board to ensure reproducibility. A planning CT scan was acquired from the mandible to the upper abdomen using 3-mm slice thickness.

Contouring was performed according to ESTRO and ICRU-83 guidelines [8] [11] :

Special attention was given to contouring the heart and left anterior descending (LAD) artery in left-sided cases due to their proximity to the irradiation field.

Treatment plans were generated using the Monaco TPS (Elekta), which utilizes the Monte Carlo algorithm for high-precision dose calculation. Patient CT datasets were imported into the TPS for 3DCRT plan development. Key planning steps included:

Dose-volume histograms (DVHs) were used to evaluate dose distribution and ensure compliance with international standards.

Treatment was delivered using 6 MV photon beams to a total dose of 40.05 Gy in 15 fractions (2.67 Gy per fraction). The following dosimetric constraints were applied.

To reduce heart dose in left-sided breast cancer cases, the following techniques were employed:

The treatment plans achieved satisfactory target volume coverage across all cases. Dose-volume histogram (DVH) analysis confirmed that the planning target volume (PTV) received adequate dose coverage, meeting International Commission on Radiation Units and Measurements (ICRU) Report 83 criteria [11] .

These results confirm the clinical feasibility of hypofractionated 3DCRT in maintaining uniform dose distribution while meeting international dose coverage standards.

In left-sided breast cancer patients, specific measures were taken to minimize radiation dose to cardiac structures, especially the heart and the left anterior descending (LAD) artery.

These findings demonstrate the effectiveness of DIBH and beam optimization in reducing cardiac radiation exposure in left-sided cases, aligning with cardiotoxicity prevention strategies outlined in prior studies [7] [9] .

The lungs, particularly the ipsilateral (left) lung in left-sided cases, were evaluated for radiation dose exposure.

These parameters were within established safety thresholds and reflect proper beam shaping and lung protection during planning.

All patients completed the prescribed course of hypofractionated 3DCRT without interruption.

These outcomes support the clinical safety and efficacy of 3DCRT in hypofractionated schedules, particularly when using cardiac-sparing techniques such as DIBH and FIF [6] [10] .

This study contributes practical insights into how high-quality breast radiotherapy can be delivered in low-resource environments:

Many radiotherapy centers in LMICs operate with outdated or poorly maintained equipment, including linear accelerators without multi-leaf collimators (MLCs), basic treatment planning systems, and limited imaging capabilities. These deficiencies hinder precise tumor targeting and organ-at-risk (OAR) sparing [4] [12] . Additionally, unreliable power supplies and lack of cooling systems disrupt consistent treatment delivery.

The successful implementation of 3DCRT requires a multidisciplinary team of radiation oncologists, medical physicists, and radiotherapy technologists. However, LMICs often suffer from critical shortages of trained professionals. This is due to limited access to specialized training, low salaries, and workforce migration to higher-income countries [6] [10] . As a result, treatment planning may lack the expertise required for accurate contouring, dose calculation, and verification.

The high upfront costs of radiotherapy equipment, maintenance, and planning software pose a substantial barrier for many public health systems in LMICs. Hypofractionation is cost-effective in the long term, but the initial investment in infrastructure and technology is prohibitive without sustained government or donor funding. Additionally, patients often bear the cost of care out-of-pocket, which can discourage them from completing treatment [5] .

Comprehensive quality assurance (QA) systems are essential to ensure treatment accuracy and patient safety. However, many low-resource centers lack essential QA tools, such as ion chambers, water phantoms, and software for dose verification. Inadequate or irregular QA practices increase the risk of dosimetric errors, potentially compromising tumor control or increasing toxicity [9] .

Patients in rural or underserved regions frequently face transportation difficulties, poor health literacy, and economic constraints that affect treatment compliance. Long travel distances to centralized cancer centers, combined with indirect costs like lost wages or accommodation, can result in treatment delays, missed sessions, or premature discontinuation [8] .

Accurate simulation and contouring are foundational to effective 3DCRT planning. However, many facilities lack access to modern CT simulators or imaging modalities required for three-dimensional planning. In such cases, empirical or two-dimensional planning may still be in use, undermining the accuracy and reproducibility of hypofractionated treatment delivery [11] .

While hypofractionated radiotherapy is generally well tolerated, managing even mild toxicities (e.g., skin reactions, fatigue) requires supportive care infrastructure and reliable follow-up systems. Unfortunately, many LMICs lack robust follow-up mechanisms, leading to underreporting of adverse events and reduced long-term surveillance of treatment outcomes [3] .

The majority of clinical evidence supporting hypofractionated 3DCRT originates from high-income countries with access to advanced technology. LMICs often lack local data on treatment outcomes, toxicity profiles, or cost-effectiveness, making it difficult to formulate evidence-based protocols suitable for their populations [7] . Without localized studies, treatment strategies may not account for differences in tumor biology, patient demographics, or health infrastructure.

State-of-the-art treatment planning requires sophisticated software capable of generating precise dose distributions. However, many facilities in LMICs still rely on outdated or basic planning systems with limited functionality. These systems often cannot incorporate detailed OAR constraints or generate accurate three-dimensional dose distributions, compromising both safety and effectiveness [2] .

Despite these challenges, several strategies can improve the delivery of 3DCRT hypofractionated radiotherapy in low-resource settings:

One of the core responsibilities of the medical physicist is the development and verification of accurate treatment plans in collaboration with radiation oncologists.

During the simulation process, medical physicists ensure that patient positioning and imaging protocols are optimized for reproducibility and anatomical accuracy.

Accurate delivery of hypo fractionated doses depends on well-calibrated and properly commissioned linear accelerators (LINACs).

Before initiating treatment, physicists verify each patient’s treatment plan through independent QA procedures.

Although adaptive radiotherapy is limited in many low-resource settings, medical physicists play a key role in monitoring any anatomical changes during treatment.

Medical physicists are responsible for maintaining radiation safety for patients, staff, and the public.

In resource-constrained environments, medical physicists often extend their roles to training and protocol development.

Summary of Responsibilities:

While this retrospective analysis provides encouraging results, prospective multi-center studies are needed to validate long-term clinical outcomes, including locoregional control, cardiac morbidity, and overall survival. Incorporating quality-of-life metrics will also be essential to assess patient-reported outcomes.

Artificial intelligence can improve efficiency and accuracy in treatment planning by automating contouring, beam optimization, and plan evaluation. AI-driven platforms may reduce planning time and inter-observer variability, thereby standardizing care across diverse clinical settings [7] . Pilot implementation of AI-assisted workflows in Bangladesh could demonstrate feasibility and establish cost-effectiveness, particularly in high-volume public centers.

National efforts should prioritize:

These interventions will empower facilities to implement evidence-based protocols without dependence on expensive technologies like IMRT or proton therapy.

Creating a centralized registry to track treatment protocols, dosimetric parameters, and outcomes would provide critical data for quality improvement and research. Bangladesh’s oncology institutions should collaborate on standardized data collection and reporting to support evidence-based policymaking.