Deep inspiration breath hold in post-operative radiotherapy for right breast cancer: a retrospective analysis

Clinical benefits of deep inspiration breath-hold in postoperative radiotherapy for right-sided breast cancer: a meta-analysis

OBJECTIVES

The study aims to emphasize the clinical importance of the Deep Inspiration Breath Hold (DIBH) technique by quantifying its dosimetric advantages over Free Breathing (FB) in reducing radiation exposure to the heart, liver, and lungs for right-sided breast cancer patients. This evidence supports its potential for routine clinical use to mitigate radiation-induced toxicity.

METHODS

A systematic retrieval of controlled trials comparing DIBH and FB techniques in postoperative radiotherapy for right-sided breast cancer was conducted utilizing the PubMed, Embase, Cochrane Library, and Web of Science databases. The primary outcomes assessed included the doses of adjacent normal tissues (heart, liver, and lungs). Summary standardized mean differences (SMD) along with 95% confidence intervals (CI) were computed, respectively. StataMP 17 software was selected to perform data analysis.

RESULTS

The study encompassed an analysis of 313 patients derived from seven online studies, comprising 168 individuals in the DIBH group and 269 individuals in the FB group. The findings indicated that the DIBH group received significantly lower irradiation doses to the heart, liver, and lungs in comparison to the FB group, with statistical significance (heart dose: SMD = -0.63, 95% CI -0.85 to -0.41, P < 0.05; liver dose: SMD = -1.15, 95% CI -1.91 to -0.38, P < 0.05; lung dose: SMD = -0.79, 95% CI -1.23 to -0.35, P < 0.05).

CONCLUSION

This meta-analysis indicated that the application of DIBH during postoperative radiotherapy for right-sided breast cancer markedly decreases radiation exposure to the heart, liver, and lungs, while maintaining consistent tumor dose coverage.

CLINICAL TRIAL NUMBER

Not applicable.

Application and dosimetric comparison of surface-guided deep inspiration breath-hold for lung stereotactic body radiotherapy

Respiratory motion management is the crucial challenge for safe and effective application of lung stereotactic body radiotherapy (SBRT). The present study implemented lung SBRT treatment in voluntary deep inspiration breath-hold (DIBH) with surface-guided radiotherapy (SGRT) system and evaluated the geometric and dosimetric benefits of DIBH to organs-at-risk (OARs), aiming to advising the choice between DIBH technology and conventional free breathing 4 dimensions (FB-4D) technology. Five patients of lung SBRT treated in DIBH with SGRT at our institution were retrospectively analyzed. CT scans were acquired in DIBH and FB-4D, treatment plans were generated for both respiratory phases. The geometric and dosimetry of tumor, ipsilateral lung, double lungs and heart were compared between the DIBH and FB-4D treatment plans. In terms of target coverage, utilizing DIBH significantly reduced the mean plan target volume (PTV) by 21.9% (p = 0.09) compared to FB-4D, the conformity index (CI) of DIBH and FB-4D were comparable, but the dose gradient index (DGI) of DIBH was higher. With DIBH expanding lung, the volumes of ipsilateral lung and double lungs were 2535.1 ± 403.0cm3 and 4864.3 ± 900.2cm3, separately, 62.2% (p = 0.009) and 73.1% (p = 0.009) more than volumes of ipsilateral lung (1460.03 ± 146.60cm3) and double lungs (2811.25 ± 603.64cm3) in FB-4D. The heart volume in DIBH was 700.0 ± 146.1cm3, 11.6% (p = 0.021) less than that in FB-4D. As for OARs protection, the mean dose, percent of volume receiving > 20Gy (V20) and percent of volume receiving > 5Gy (V5) of ipsilateral lung in DIBH were significantly lower by 33.2% (p = 0.020), 44.0% (p = 0.022) and 24.5% (p = 0.037) on average, separately. Double lungs also showed significant decrease by 31.1% (p = 0.019), 45.5% (p = 0.024) and 20.9% (p = 0.048) on average for mean dose, V20 and V5 in DIBH. Different from the lung, the mean dose and V5 of heart showed no consistency between DIBH and FB-4D, but lower maximum dose of heart was achieved in DIBH for all patients in this study. Appling lung SBRT in DIBH with SGRT was feasibly performed with high patient compliance. DIBH brought significant dosimetric benefits to lung, however, it caused more or less irradiated heart dose that depend on the patients' individual differences which were unpredictable.

Deep inspirational breast hold (DIBH) for right breast irradiation: Improved sparing of liver and lung tissue

Objective

To reduce liver and lung dose during right breast irradiation while maintaining optimal dose to the target volume. This dose reduction has the potential to decrease acute side effects and long-term toxicity.

Materials and Methods

16 patients treated with radiation therapy for localized carcinoma of the right breast were included retrospectively. For the planning CT, each patient was immobilised on an indexed board with the arms placed above the head. CT scans were acquired in free-breathing (FB) as well as with deep inspiration breath hold (DIBH). Both scans were acquired with the same length. Planning target volumes (PTV's) were created with a 5 mm margin from the respective clinical target volumes (CTV's) on both CT datasets. The liver was outlined as scanned. Dose metrics evaluated were as follows: differences in PTV coverage, dose to the liver (max, mean, V90%, V50%, V30%), dose to lung (mean, V20Gy, relative electron density) and dose to heart (Dmax). The p-values were calculated using Wilcoxon signed-rank tests. A p-value was significant when <0.05.

Results

Differences in PTV coverage between plans using FB and DIBH were less than 2 %. Maximum liver dose was significantly less using DIBH: 17.5 Gy versus FB: 40.3 Gy (p < 0.001). The volume of the liver receiving 10 % of the dose was significantly less using DIBH with 1.88 cm3 versus 72.2 cm3 under FB (p < 0.001). The absolute volume receiving 20 Gy in the right lung was larger using DIBH: 291 cm3 versus 230 cm3 under FB (p < 0.001) and the relative volume of lung receiving dose greater than 20 Gy was smaller with DIBH: 11.5 % versus 14 % in FB (p = 0.007). The relative electron density of lung was significantly less with DIBH: 0.59 versus 0.62 with FB, (p < 0.001). This suggests that the lung receives less dose due to its lower density when using DIBH.

Conclusion

Radiation of the right breast using DIBH spares liver and lung tissue significantly and thus carries the potential of best practice for right sided breast cancer.

Dose Volume and Liver Function Test Relationship following Radiotheraphy for Right Breast Cancer: A Multicenter Study

OBJECTIVE

The liver is a critical organ at risk during right breast radiotherapy (RT). Liver function tests (LFTs) such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT) serve as biochemical markers for hepatobiliary damage. In this multicenter cross-sectional study, the effects of liver dose-volume on changes in LFTs pre- and post-RT in patients treated for right breast cancer were evaluated.

MATERIALS AND METHODS

Between January 2019 and November 2022, data from 100 patients who underwent adjuvant right breast RT across three centers were retrospectively assessed. Target volumes and normal structures were contoured per the RTOG atlas. Patients were treated with a total dose of 50 Gy in 25 fractions to the CTV, followed by a boost to the tumor bed where indicated. The percentage change in LFT values in the first two weeks post-RT was calculated. Statistics were analyzed with SPSS version 22 software, with significance set at p < 0.05. Statistical correlation between liver doses (in cGy) and the volume receiving specific doses (Vx in cc) on the change in LFTs were analyzed using Kolmogorov-Smirnov, Mann-Whitney U test.

RESULTS

The median age among the 100 patients was 56 (range: 29-79). Breast-conserving surgery was performed on 75% of the patients. The most common T and N stages were T1 (53%) and N0 (53%), respectively. None of the patients had distant metastasis or simultaneous systemic treatment with RT. A total of 67% of the treatments utilized the IMRT technique and 33% VMAT. The median CTV volume was 802 cc (range: 214-2724 cc). A median boost dose of 10 Gy (range: 10-16 Gy) was applied to 28% of the patients with electrons and 51% with IMRT/VMAT. The median liver volume was 1423 cc (range: 825-2312 cc). Statistical analyses were conducted on a subset of 57 patients for whom all three LFT values were available both pre- and post-RT. In this group, the median values for AST, ALT, and GGT increased up to 15% post-RT compared to pre-RT, and a median liver Dmean below 208 cGy was found significant. While many factors can influence LFT values, during RT planning, attention to liver doses and subsequent regular LFT checks are crucial.

CONCLUSION

Due to factors such as anatomical positioning, planning technique, and breast posture, the liver can receive varying doses during right breast irradiation. Protecting patients from liver toxicity secondary to RT is valuable, especially in breast cancer patients with a long-life expectancy. Our study found that, even in the absence of any systemic treatment or risk factors, there was an average increase of nearly 15% in enzymes, indicating acute liver damage post-RT compared with pre-RT. Attention to liver doses during RT planning and regular follow-up with LFTs is essential.

Deep inspiration breath hold: dosimetric benefits to decrease cardiac dose during postoperative radiation therapy for breast cancer patients

Background

Postoperative radiation therapy (RT) is the standard treatment for almost all patients diagnosed with breast cancer. Even with modern RT techniques, parts of the heart may still receive higher doses than those recommended by clinically validated dose limit restrictions, especially when the left breast is irradiated. Deep inspiration breath hold (DIBH) may reduce irradiated cardiac volume compared to free breathing (FB) treatment. This study aimed to evaluate the dosimetric impact on the heart and left anterior descending coronary artery (LAD) in FB and DIBH RT planning in patients with left breast cancer.

Materials and methods

A retrospective cohort study of women diagnosed with left-sided breast cancer submitted to breast surgery followed by postoperative RT from 2015 to 2019. All patients were planned with FB and DIBH and hypofractionated dose prescription (40.05 Gy in 15 fractions).

Results

68 patients were included in the study. For the coverage of the planned target volume evaluation [planning target volume (PTV) eval] there was no significant difference between the DIBH versus FB planning. For the heart and LAD parameters, all constraints evaluated favored DIBH planning, with statistical significance. Regarding the heart, median V16.8 Gy was 2.56% in FB vs. 0% in DIBH (p < 0.001); median V8.8 Gy was 3.47% in FB vs. 0% in DIBH (p < 0.001) and the median of mean heart dose was 1.97 Gy in FB vs. 0.92 Gy in DIBH (p < 0.001). For the LAD constraints D2% < 42 Gy, the median dose was 34.87 Gy in FB versus 5.8 Gy in DIBH (p < 0.001); V16.8 Gy < 10%, the median was 15.87% in FB versus 0% in DIBH (p < 0.001) and the median of mean LAD dose was 8.13Gy in FB versus 2.92Gy in DIBH (p < 0.001).

Conclusions

The DIBH technique has consistently demonstrated a significant dose reduction in the heart and LAD in all evaluated constraints, while keeping the same dose coverage in the PTV eval.

Surface guided 3DCRT in deep-inspiration breath-hold for left sided breast cancer radiotherapy: implementation and first clinical experience in Iran

Background

The aim of the study is to evaluate the overall accuracy of the surface-guided radiotherapy (SGRT) workflow through a comprehensive commissioning and quality assurance procedures and assess the potential benefits of deep-inspiration breath-hold (DIBH) radiotherapy as a cardiac and lung dose reduction approach for left-sided breast cancer irradiation.

Materials and methods

Accuracy and reproducibility of the optical surface scanner used for DIBH treatment were evaluated using different phantoms. Patient positioning accuracy and reproducibility of DIBH treatment were evaluated. Twenty patients were studied for treatment plan quality in target dose coverage and healthy organ sparing for the two different treatment techniques.

Results

Reproducibility tests for the surface scanner showed good stability within 1 mm in all directions. The maximum position variation between applied shifts on the couch and the scanner measured offsets is 1 mm in all directions. The clinical study of 200 fractions showed good agreement between the surface scanner and portal imaging with the isocenter position deviation of less than 3 mm in each lateral, longitudinal, and vertical direction. The standard deviation of the DIBH level showed a value of < 2 mm during all evaluated DIBHs. Compared to the free breathing (FB) technique, DIBH showed significant reduction of 48% for heart mean dose, 43% for heart V25, and 20% for ipsilateral lung V20.

Conclusion

Surface-guided radiotherapy can be regarded as an accurate tool for patient positioning and monitoring in breast radiotherapy. DIBH treatment are considered to be effective techniques in heart and ipsilateral lung dose reductions for left breast radiotherapy.