Irradiation Of Left-sided Breast Cancer Research Articles

Left-sided Breast Cancer Irradiation With Deep Inspiration Breath-hold: Changes in Heart and Lung Dose in Two Periods

Post-operative radiotherapy for breast cancer can increase cardiac disease in a dose-dependent manner. In this study we show the reduction of dose to heart and left anterior descending artery (LAD) which can be achieved by using "Deep inspiration breath-hold" (DIBH) technique.Tangential 3D-planned radiation was delivered to 357 patients with left-sided breast cancer, 159 of them with the DIBH technique. A distinction was made according to fractionation scheme.The mean heart dose was significantly reduced by DIBH from 2.64 Gy to 1.39 Gy (p<0.001). The mean dose to the LAD was significantly reduced from 5.68 Gy to 3.88 Gy (p<0.001). Mean dose and volume receiving 5, 10 and 15 Gy of ipsilateral lung were higher with both hypofractionated schedule and conventional fractionation in the DIBH group.DIBH in left-sided breast irradiation is an effective method of reducing the radiogenic heart dose.

The Impact of the Semi-Lateral Decubitus Position Regarding Dose Distribution to the Ipsilateral Axilla in Comparison to Supine Position for Left Sided Breast Cancer Irradiation

The Impact of the Semi-Lateral Decubitus Position Regarding Dose Distribution to the Ipsilateral Axilla in Comparison to Supine Position for Left Sided Breast Cancer Irradiation

Reduction of cardiac and coronary artery doses in irradiation of left-sided breast cancer during inspiration breath hold : Aplanning study.

The radiation dose received by the heart during adjuvant left-sided breast irradiation plays acrucial role in development of late toxicity. Although the absolute risk of cardiotoxicity can be reduced with modern irradiation techniques, cardiotoxic chemotherapy increases the risk of late damage. Thus, the radiation dose to the heart should be minimized. This study evaluated the influence of different amplitudes of inspiration breath hold (IBH) during simulated left-sided breast irradiation on cardiac doses compared to free breathing (FB). CT data of 11lung cancer patients were retrospectively used as left-sided pseudo-breast cancer cases. Two CT scans were used, one during IBH and one during FB, and two treatment plans were generated. Relevant heart, lung, and left anterior descending artery (LAD) parameters were derived from dose-volume histograms. The normal tissue complication probabilities (NTCPs) for the heart were calculated based on the relative seriality model. Inspiration depth was quantified using chest volume and diameter, and correlated thereafter to apossible sparing of heart tissue. Mean reduction of heart dose for IBH compared to FB was 40 % (1.65 vs. 0.99Gy; p= 0.007). Maximum dose to the heart and LAD could be decreased by 33 % (p= 0.011) and 43 % (p= 0.024), respectively. The mean anteroposterior shift was 5mm (range 0.9-9.5mm). Significant negative correlations between the relative change in LAD mean dose and the mean thoracic diameter and volume change, as well as with the absolute change in thoracic diameter were seen. The NTCP for cardiac mortality could be decreased by about 78 % (p= 0.017). For left-sided breast cancer patients, cardiac doses can be significantly decreased with tangential irradiation and IBH.

EP-1666: A modified left-sided breast cancer irradiation in Tomotherapy: comparison to hybrid-IMRT technique

EP-1666: A modified left-sided breast cancer irradiation in Tomotherapy: comparison to hybrid-IMRT technique

Automated daily breath hold stability measurements by real-time imaging in radiotherapy of breast cancer

Background and purposeBreath hold is increasingly used for cardiac sparing in left-sided breast cancer irradiation. We have developed a fast automated method to verify breath hold stability in each treatment fraction. Material and methodsWe evaluated 504 patients treated with breath hold. Moderate deep inspiration breath hold was audio-guided. Medial and lateral large tangential field segments were delivered in a single breath hold and movieloops of these fields were acquired with an EPID. The thoracic wall position was automatically detected in each frame and the full range of thoracic wall motion (RTWM) was determined. If the RTWM >4mm more than 3 times, the patient was excluded from breath hold treatment if further coaching did not yield improvement. ResultsUnstable breath hold was observed in 2.8% of the patients. However, this frequency dropped from 9.5% in the first 6months to 1.6% in the subsequent 16months. The 97% of patients with proper breath hold showed excellent stability: the average RTWM was 0.9±0.5mm. The reproducibility of the breath hold depth was confirmed by (1) the small difference between the thoracic wall positions in the medial and lateral fields within one fraction and (2) the setup errors of breath hold patients showed no significant differences with those of right-sided breast patients. ConclusionsWe have developed and clinically applied an imaging tool to automatically determine stability of breath holds in each treatment fraction during beam delivery.

Prospective Assessment of Deep Inspiration Breath Hold Using 3-Dimensional Surface Tracking for Irradiation of Left-Sided Breast Cancer

Deep inspiration breath hold (DIBH) is used to reduce dose and volume of cardiac irradiation during radiation therapy (RT) for breast cancer (BC). Patient subgroups most likely to benefit from DIBH and the effect of DIBH on treatment time remain largely unknown. We sought to identify predictors for the use of DIBH and to quantify differences in dosimetry and treatment time using a large, prospective registry of patients (pts) with BC. One hundred forty-eight pts (ages 26-81) with Stage I-IV left BC were enrolled on a prospective registry from 2011-2014. Pts with any type of breast surgery, systemic therapy and RT fields were included. All pts were deemed potential candidates for DIBH and were simulated with both free-breathing (FB) and DIBH. RT was delivered using either FB or DIBH scans based on physician assessment of tolerance, compliance, and anatomy, without formal dosimetric comparison. Alternate scans were also planned using deformable registration to include identical volumes within RT fields. DIBH pts were monitored using a real-time surface tracking system, AlignRT®. Baseline characteristics and treatment times were compared using Fisher’s exact test and Wilcoxon Rank Sum test. Coefficient of variation (CV) measured the dispersion of treatment times. Dosimetric endpoints were compared across paired DIBH and FB scans using Wilcoxon signed rank test. Linear regression was used to identify predictors for change in mean heart dose (ΔMHD) across paired scans. We treated 38 pts with FB and 110 with DIBH. FB pts were significantly older (median: 58 vs. 49.5 years; P=.002), more likely to have pre-existing heart (11% vs. 1%; P=.02) and lung disease (13% vs. 4%; P=.05), and less likely to receive chemotherapy (42% vs. 66%; P=.01) or immediate reconstruction (11% vs. 34%; P=.01) relative to DIBH pts. MHD (138 cGy vs. 256 cGy), heart V5 (3.8% vs. 8%), heart V30 (0% vs. 1.5%), mean lung dose (923 cGy vs. 992 cGy), and lung V20 (17.1% vs. 18.7%) were all significantly lower in DIBH than in paired FB plans. Of 146 evaluable pts, DIBH resulted in >20 cGy improvement in MHD in 107 (range: 22-881 cGy), neutral change in 25, and >20 cGy increase in MHD in 14 (range: 21-153 cGy). Treatment times were not significantly different between DIBH and FB pts (median 4.2 min vs. 3.8 min; P=.87), but DIBH pts had greater variability in times (P=.0002). On multivariate analysis, younger age (4.18 cGy/yr; P<.0001); higher BMI (6.06 cGy/kg/m2; P=.0018) and larger change in lung volumes (130 cGy/L; P = 0.003) were associated with greater ΔMHD. DIBH is an effective technique that improves cardiac dosimetry without significantly affecting treatment time in most pts receiving breast RT. As expected, greater inspiratory lung volumes augment the benefit in DIBH. As the benefit of DIBH was not seen in all pts, pts should be scanned with both FB and DIBH before choosing a treatment approach.

Prospective assessment of deep inspiration breath-hold using 3-dimensional surface tracking for irradiation of left-sided breast cancer

PurposeDeep inspiration breath hold (DIBH) is used to decrease cardiac irradiation during radiation therapy (RT) for breast cancer. The patients most likely to benefit and the impact on treatment time remain largely unknown. We sought to identify predictors for the use of DIBH and to quantify differences in dosimetry and treatment time using a prospective registry. Methods and materialsA total of 150 patients with left breast cancer were enrolled. All patients were simulated with both free breathing (FB) and DIBH. RT was delivered by either modality. Alternate scans were planned with use of deformable registration to include identical RT volumes. DIBH patients were monitored by a real-time surface tracking system, AlignRT (Vision RT, Ltd, London, United Kingdom). Baseline characteristics and treatment times were compared by Fisher exact test and Wilcoxon rank sum test. Dosimetric endpoints were analyzed by Wilcoxon signed rank test, and linear regression identified predictors for change in mean heart dose (∆MHD). ResultsWe treated 38 patients with FB and 110 with DIBH. FB patients were older, more likely to have heart and lung disease, and less likely to receive chemotherapy or immediate reconstruction (all P < .05). Treatment times were not significantly different, but DIBH patients had greater variability in times (P = .0002). Of 146 evaluable patients, DIBH resulted in >20 cGy improvement in MHD in 107 patients but a >20 cGy increase in MHD in 14. Both MHD and lung V20 were significantly lower in DIBH than in paired FB plans. On multivariate analysis, younger age (4.18 cGy per year; P < .0001), higher body mass index (6.06 cGy/kg/m2; P = .0018), and greater change in lung volumes (130 cGy/L; P = .003) were associated with greater ∆MHD. ConclusionsDIBH improves cardiac dosimetry without significantly impacting treatment time in most patients. Greater inspiratory lung volumes augment this benefit. Because the improvement with DIBH was not uniform, patients should be scanned with both FB and DIBH.

Left-sided breast cancer irradiation using rotational and fixed-field radiotherapy

The 3-dimensional conformal radiotherapy (3DCRT) technique is the standard for breast cancer radiotherapy. During treatment planning, not only the coverage of the planning target volume (PTV) but also the minimization of the dose to critical structures, such as the lung, heart, and contralateral breast tissue, need to be considered. Because of the complexity and variations of patient anatomy, more advanced radiotherapy techniques are sometimes desired to better meet the planning goals. In this study, we evaluated external-beam radiation treatment techniques for left breast cancer using various delivery platforms: fixed-field including TomoDirect (TD), static intensity-modulated radiotherapy (sIMRT), and rotational radiotherapy including Elekta volumetric-modulated arc therapy (VMAT) and tomotherapy helical (TH). A total of 10 patients with left-sided breast cancer who did or did not have positive lymph nodes and were previously treated with 3DCRT/sIMRT to the entire breast were selected, their treatment was planned with Monaco VMAT, TD, and TH. Dosimetric parameters including PTV coverage, organ-at-risk (OAR) sparing, dose-volume histograms, and target minimum/maximum/mean doses were evaluated. It is found that for plans providing comparable PTV coverage, the Elekta VMAT plans were generally more inhomogeneous than the TH and TD plans. For the cases with regional node involvement, the average mean doses administered to the heart were 9.2 (± 5.2) and 8.8 (± 3.0)Gy in the VMAT and TH plans compared with 11.9 (± 6.4) and 11.8 (± 9.2)Gy for the 3DCRT and TD plans, respectively, with slightly higher doses given to the contralateral lung or breast or both. On average, the total monitor units for VMAT plans are 11.6% of those TH plans. Our studies have shown that VMAT and TH plans offer certain dosimetric advantages over fixed-field IMRT plans for advanced breast cancer requiring regional nodal treatment. However, for early-stage breast cancer fixed-field radiotherapy is potentially more beneficial in terms of OAR sparing.

Clinical Results of Image-Guided Deep Inspiration Breath Hold Breast Irradiation

To evaluate the feasibility, cardiac dose reduction, and the influence of the setup error on the delivered dose for fluoroscopy-guided deep inspiration breath hold (DIBH) irradiation using a cone-beam CT for irradiation of left-sided breast cancer patients. Nineteen patients treated according to the DIBH protocol were evaluated regarding dose to the ipsilateral breast (or thoracic wall), heart, (left ventricle [LV] and left anterior descending artery [LAD]), and lung. The DIBH treatment plan was compared to the free-breathing (FB) treatment planning and to the dose data in which setup error was taken into account (i.e., actual delivered dose). The largest setup variability was observed in the direction perpendicular to the RT field (μ = -0.8 mm, Σ = 2.9 mm, σ = 2.0 mm). The mean (D(mean)) and maximum (D(max)) doses of the DIBH treatment plan was significantly lower compared with the FB treatment plan for the heart (34% and 25%, p < 0.001), LV (71% and 28%, p < 0.001), and LAD (52% and 39.8%, p < 0.001). For some patients, large differences were observed between the heart D(max) according to the DIBH treatment plan and the actual delivered dose (up to 71%), although D(max) was always smaller than the planned FB dose (mean group reduction = 29%, p < 0.001). The image-guided DIBH treatment protocol is a feasible irradiation method with small setup variability that significantly reduces the dose to the heart, LV, and LAD.

Comparison of conventional inserts and an add-on electron MLC for chest wall irradiation of left-sided breast cancer

Background. Collimation of irregularly shaped clinical electron beams is currently based on electron inserts made of low melting point alloys. The present investigation compares a conventional electron applicator with insert and add-on eMLC-based dose distributions in the postoperative chest wall irradiation of left-sided breast cancer. Material and methods. Voxel Monte Carlo++ (VMC++) calculated dose distributions related to electron fields were compared with 10 left-sided breast cancer patients after radical mastectomy. The prescription dose was 50 Gy at a build-up maximum. The same dose was prescribed for the ipsilateral axillary, parasternal and supraclavicular lymph nodes that were treated with photons and calculated with a pencil beam algorithm. The insert beams were shaped with 1.5 cm thick Wood's metal electron inserts in an electron applicator of a Varian 2100 C/D linac. Doses for the eMLC-shaped beams were calculated for an eMLC prototype with 2 cm thick and 5 mm wide steel leaves. The same collimator-to-surface distance (CSD) of 5.8 cm was used for both collimators. Results. The mean PTV dose was slightly higher for the eMLC plans (50.7 vs 49.5 Gy, p<0.001, respectively). The maximum doses assessed by D5% for the eMLC and insert were 60.9 and 59.1 Gy (p<0.001). The difference was due to the slightly higher doses near the field edges for the eMLC. The left lung V20 volumes were 34.5% and 34.0% (p<0.001). There was only a marginal difference in heart doses. Discussion: Despite a slight increase of maximum dose in PTV the add-on electron MLC for chest wall irradiation results in practically no differences in dose distributions compared with the present insert-based collimation.

SU‐FF‐T‐419: The Impact of Gating On the Reduction of Heart Doses for Left Sided Breast Cancer Irradiation

Purpose: Because there are indications for an increased risk of cardiovascular diseases after radiotherapy of the left chest wall the dose to the heart should be reduced as far as possible. With respiratory gating technique irradiation can be restricted only to the inspiratory plateau phase. We investigated in all patients with left sided breast cancer dose reduction to the heart when treated only in the inspiration phase compared with not gated treatments. Materials and Methods: Between Sept 2004 and Feb 2006 107 patients with left sided breast cancer were treated with respiratory gating technique based on a retrospective 4D CT scan. We performed for all of these patients a normal and a respiratory gated planning CT. Planning was done with the same treatment parameters in both CT. DVH for the entire heart and the anterior left ventricle wall were calculated. All patients were treated with 2 Gy single dose to a total dose of 50 Gy to the entire left breast/chest wall. 68 patients received an additional boost of 10 Gy. Results: The mean dose to the entire heart was 0.7 Gy without and 0.6 Gy with respiratory gating (p=0.04) whereas the mean maximal dose was 40.2 Gy without and 11.7 Gy with respiratory gating (p=0.0003). The anterior heart wall receives 2.4 Gy without and 1.2 Gy with respiratory gating (p=0.0001) with a mean maximal dose of 39.6 Gy without and 10.1 Gy with respiratory gating (p=0.0004). Conclusion: 4D analysis has shown that the distance between the PTV and the heart is influenced by two separate parameters. Besides the movements of the chest wall the heart is pushed into the irradiated volume also by the diaphragm. Respiratory gating and irradiation only in the inspiratory phase significantly reduces radiation doses to the heart and especially to the anterior heart wall.