Dosimetric comparison between interstitial brachytherapy and volumetric-modulated arc therapy for tumor bed boost in breast cancer

Predictors of poor cosmesis in breast cancer patients treated with adjuvant whole breast radiation therapy plus high-dose-rate interstitial brachytherapy boost after breast conservation surgery

Purpose

To identify patient, tumor, and treatment-related factors, which predict cosmesis in breast cancer survivors treated with adjuvant whole breast irradiation (WBI) plus high-dose-rate (HDR) multicatheter interstitial brachytherapy (MIBT) boost after breast conservation surgery.

Material and methods

At least 12 months after completion of radiotherapy, cosmetic outcomes were measured both objectively with BCCT.core software (using a front view digital photograph), and subjectively according to Harvard's criteria. MIBT dose fractionation regimen was 13.6 Gy/4 fractions (bid). To evaluate the correlation between cosmetic scores and dose-volume histogram (DVH) parameters, WBI and MIBT plans were retrospectively analyzed, and ipsilateral skin and breast biologically equivalent dosimetric indices were recorded (α/β = 3 Gy). A multivariate ordinal logistic regression model was used for statistical analysis.

Results

Twenty-eight consecutive patients were enrolled into this study. The median time from completion of radiation therapy to cosmesis scoring was 18 months. In evaluation with BCCT.core software, no patient was scored as excellent. Cosmesis was good in 18%, fair in 50%, and poor in 32% of patients. According to Harvard's scale, 10.5% of patients had excellent cosmesis, and 43%, 28.5%, and 18% of patients had good, fair, and poor scores, respectively. In univariate analysis, patients with higher absolute MIBT V29Gy (cc), those treated with irradiation of regional lymphatics (odds ratio ≈ 5), and patients with larger breast volumes had statistically significant lower Harvard's scores. In the multivariate model, none of the mentioned factors remained statistically significant, except for a trend for poorer cosmesis in patients with higher absolute MIBT V29Gy (p-value = 0.066).

Conclusions

Based on the results of this study, MIBT breast V29Gy, regional nodal irradiation, and larger breast volumes are the potential factors, which could predict cosmesis.

The value of brachytherapy in the age of advanced external beam radiotherapy: a review of the literature in terms of dosimetry

Brachytherapy (BT) has long been used for successful treatment of various tumour entities, including prostate, breast and gynaecological cancer. However, particularly due to advances in modern external beam techniques such as intensity-modulated radiotherapy (IMRT), volume modulated arc therapy (VMAT) and stereotactic body radiotherapy (SBRT), there are concerns about its future. Based on a comprehensive literature review, this article aims to summarize the role of BT in cancer treatment and highlight its particular dosimetric advantages. The authors conclude that image-guided BT supported by inverse dose planning will successfully compete with high-tech EBRT in the future and continue to serve as a valuable modality for cancer treatment.