Partial Breast Brachytherapy Research Articles

SU-E-T-596: High Dose Brachytherapy Planning of a Left Breast Cancer Patient with in Situ Pacemaker:

Purpose: To investigate the benefits of multilumen partial breast Brachytherapy device, SAVI, in reducing dose to in situ pacemakers in patients with cancer of the left breast. Methods: A left breast cancer patient with an in situ pacemaker underwent breast conservative surgery and was referred for Partial Breast Irradiation (PBI) using Ir‐192 High Dose Rate Brachytherapy. The preliminary estimation of the pacemaker dose from a pre‐insertion CT study was about 8 % of the prescribed dose which exceeded the generally accepted dose of 2Gy. The challenge was to use a suitable applicator to treat the tumor bed and 1 cm margin without exceeding the 2Gy limit to the pacemaker and the leads. A seven catheter SAVI device was selected and implanted in the left breast in an optimal direction and a 3D treatment plan was generated following a post insertion CT scan, using the Oncentra Brachy treatment planning system. Several optimization tools available in the planning system namely inverse, graphical, and dose point optimization were utilized to selectively load the catheters and reduce the dose to pacemaker and leads. A set of calibrated TLD chips were used to determine the surface dose on the pacemaker, which was then compared to the calculated surface dose. The pacemaker parameters were monitored before and after the 10 fraction (bid 5days) HDR brachytherapy, by a vendor representative and were found to functioning properly. Results: Using the seven catheter SAVI device it was possible to limit the pacemaker/ leads dose to less than 2 Gy, with an overall satisfactory dose to the target volume. Conclusions: By combining the optimization tools of today's Brachytherapy planning system and a multilumen SAVI applicator, HDR partial breast irradiation can be successfully delivered for left breast cancer patients with in situ pacemaker, with out the concern of interrupting pacemaker functionality

SU-E-T-380: Evaluation of Interfraction Motion of the Strut-Adjusted Volume Implant (SAVI) Using 3D Reconstruction from CT Scout Images

Purpose: The Strut‐Adjusted Volume Implant (SAVI) is a partial breast irradiation applicator. We developed a method to reconstruct the 3D device location using scout images to provide applicator position and proper expansion verification. We also used this technique to evaluate interfraction motion. Methods: The SAVI device was implanted in a lumpectomy cavity. The patient was aligned by CT lasers and skin tattoos to ensure reproducible setup. A post‐operative CT scan was performed for treatment planning. The patient was treated in 10 fractions over the course of 5 days. Daily CT scans and anterior and lateral scout scans were acquired prior to each fraction. Radio‐opaque markers located on three of the struts were localized using a peak detection filter. The location of each marker on the 2D scout image was backprojected towards the CT x‐ray source. Each 3D marker position was reconstructed at the backprojection intersection. The 3D marker position was compared to the location in the 3D CTimage. The interfractional displacement of the device was assessed from the reconstructed marker locations. Results: The average distance (standard deviation) between the marker positions reconstructed using the scout images and the CTimages was 0.76 (0.28) mm. Using the scout image data, the average interfractional device movement (standard deviation) in the SI, AP, and LR directions, and 3D was 0.51 (0.46) mm, 0.95 (0.81) mm, 0.73 (0.61) mm, and 1.56 (0.68) mm. Conclusion: SAVI interfraction motion can be accurately measured using scout images. The patient setup for partial breast brachytherapy can be improved by correcting the applicator displacement. This proposed technique eliminates the need for CT verifications, and therefore additional dose to the patient, while still accurately identifying applicator displacement.

628 poster SHORT-COURSE ACCELERATED PARTIAL BREAST IRRADIATION (OVER 2 DAYS) IS FEASIBLE WITH THE CONTURA(r) MULTI-LUMEN BRACHYTHERAPY DEVICE

PTV_EVAL volume did not correlate with aspirated seroma volume in our study. Conclusions: In our study, seroma accumulation seemed to have a variable pattern of development with no discernible predictors of occurrence. During a course of fractionated partial breast brachytherapy, serial aspirations via vacuum port, when available, should be considered for all patients to potentially improve dosimetry and reproducibility of PTV_EVAL. Further study is needed to establish factors predictive for seroma accumulation and resultant clinical significance.

On the Feasibility of Treating to a 1.5 cm PTV for Accelerated Partial Breast Brachytherapy With a Commercial Single Entry Hybrid Applicator

Purpose: It’s well known that mediastinum, lungs, heart, spinal cord are the unwishful targets in distant radiation therapy at the parasternal zone in breast cancer patients. Different treatment-related morbidity has been observed. That was the reason for the modern radiation therapy application at this zone. It has been shown that internal mammary artery is the optimal natural pathway for the radiation sources which leads to symmetrical irradiation of internal mammary lymph nodes. Our goal was to identify the efficacy of breast cancer treatment depending on the parasternal brachytherapy using Co or Cf sources in comparison with Ir afterloading and to analyze long-term results in each group. Materials and Methods: 868 patients with central and medial location of the tumor underwent parasternal brachytherapy. In 575 women (66.2%) 60Co was used, in 194 (22.4%) 252Cf was used, and 99 (11,4%) had afterloading ‘‘Microselectron-HDR’’ irradiation with 192Ir. Medium age was 48.2 ( 15.8) years in the first group, 50.8 ( 12.6) years in the second group, and 49.7 ( 9.8) years in the third group. I stage had 98 patients (11.3%), IIA e 388 (44.7%), IIB e 202 (23,3%), IIIA e 121 (13.9%), IIIB e 59 (6.8). All women with T3 and T4 (62 e 19.8%) had standard preoperative chemotherapy. Manual installation of 60Co or 252Cf sources was performed for the time necessary for the prescribed dose to be achieved. The isodose at the specification point was 80 Gy, while at 2 cm from the medial field edge total dose was at least 36 Gy. A total dose of 45 Gy in three 15 Gy fractions was delivered to the internalmammary lymph nodes using 192Ir afterloading. Results:With a median followup of 148 months no significant difference in 15-year disease-free and overall survival was detected in all brachytherapy techniques. No significant complications associated with brachytherapy were registered. Conclusions: Ir afterloading technique we conceder to be preferable to manual Co and Cf radiation source installation due to decreased medical staff irradiation. It has become apparent that distant radiation therapy is a cause of significant morbidity, especially among long-term survivors. If the internal mammary nodes are to be treated we suggest using afterloading brachytherapy technique.

Accelerated Partial Breast Irradiation at Virginia Hospital Center: Post Hoc Analysis of Dosimetry Comparing Mammosite, Contura, and SAVI Devices

Dosimetric factors in 123 consecutive patients treated with accelerated partial breast brachytherapy using three different applicators were analyzed to evaluate mean differences across key planning variables.

Radiation exposure of the heart, lung and skin by radiation therapy for breast cancer: A dosimetric comparison between partial breast irradiation using multicatheter brachytherapy and whole breast teletherapy

Background and purposeAccelerated partial breast irradiation by means of multicatheter brachytherapy shows great promise in the modern treatment of early breast cancer combining high efficacy in preventing tumour recurrence with low levels of toxicity. The present work attempts a dosimetric comparison between this treatment modality and conventional whole breast external beam radiotherapy by looking at differences in risk organ exposure to radiation. Patients and methodsThe planning CT data sets of 16 consecutive patients with left-sided breast cancer who received external beam radiotherapy to the whole breast followed by a boost to the tumour bed using multicatheter interstitial brachytherapy after breast conserving surgery were used to create two independent physical treatment plans – one for an external radiotherapy, one for sole partial breast brachytherapy in each case assuming a total reference dose of 50Gy for each patient. Dose–volume parameters D0.1cc, D0.5cc, D1cc,D2cc, D5cc,D10cc, D25cc, D50cc, V100, V90, V50, V10, V5 for the ipsilateral lung, the heart and the adjacent skin were calculated and compared between the two treatment modalities. ResultsAll organs at risk showed a substantially lower radiation exposure in the brachytherapy plan. This was most pronounced for the heart with values differing by a factor of four. Although somewhat less marked this was also true for the ipsilateral lung and the adjacent skin with exposure ratios of three and two, respectively. ConclusionsWith the use of multicatheter interstitial brachytherapy substantial reductions in the radiation exposure of risk organs can be achieved in comparison to whole breast external beam radiotherapy. These are likely to translate into profound clinical benefits.

Analysis of Dosimetric Quantities Associated with Partial Breast Brachytherapy

Analysis of Dosimetric Quantities Associated with Partial Breast Brachytherapy

Partial Breast Brachytherapy after Lumpectomy as Salvage Treatment for Local Recurrences after Conservative Treatment of Breast Cancer: Eighteen-Year Results of a Non-randomized Comparison with Mastectomy

Purpose: To report the long-term results obtained in a prospective group of patients (pts) treated for local recurrence after conservative treatment of breast cancer treated by a second conservative surgery or by total mastectomy.

Total Treatment Time Verification for the Contura™ Multilumen Balloon

Purpose: To introduce a method of verification for the total treatment time when using the Contura™ multilumen balloon (MLB) for accelerated partial breast brachytherapy. This method is used to verify if the overall treatment time is reasonable. This method is not to be used as a replacement for the independent check as required as a standard of practice.

Initial clinical experience with the Strut-Adjusted Volume Implant brachytherapy applicator for accelerated partial breast irradiation

Purpose Accelerated partial breast irradiation is becoming increasingly popular. The Cianna single-entry high-dose-rate applicator, Strut-Adjusted Volume Implant (SAVI, Cianna Medical, Aliso Viejo, CA), contains peripheral struts allowing greater planning flexibility for small-breasted women, technically easier insertion, and normal tissue exposure minimization. This study evaluates early clinical experience. Methods and Materials Thirty patients treated with the SAVI with a median followup of 12 months were evaluated. The median age was 59.5. Tumor size averaged 0.9 cm. Fifteen cancers were ductal carcinoma in situ (50%), 1 was invasive lobular (3.3%), 4 were tubular (6.7%), and the rest infiltrating ductal (40%). Most of them were estrogen receptor (ER) positive (90%). Nine women (30%) were premenopausal. Results Dosimetry was outstanding with median V90, V150, and V200 of 96.2%, 24.8, and 12.8 cc. There were no symptomatic seromas, and one report of asymptomatic fat necrosis seen on mammogram at 1 year. In patients who had skin spacing of less than 1 cm, the median skin dose was 245 cGy/fraction. The median rib and lung dose per fraction for those patients with either structure less than 1 cm was 340 and 255 cGy (75% of prescribed dose), respectively. There have been no local recurrences to date. Conclusions Early clinical experience with the SAVI demonstrates the ease of placement of a single-entry brachytherapy device combined with the increased dose modulation of interstitial brachytherapy. Dose to normal structures has remained exceedingly low. Almost half of evaluated patients were not candidates for other single-entry brachytherapy devices because of skin spacing or breast size, demonstrating an expansion of candidates for single-entry partial breast brachytherapy.

SU-FF-T-23: Analysis of Dosimetric Quantities Associated with Partial Breast Brachytherapy

Purpose: Radiation dose to the heart and lung are a concern in accelerated partial breast irradiation (APBI). This work presents an analysis of the metrics inherent to high dose rate APBI using a brachytherapy source. Method and Materials: Five patients receiving APBI brachytherapy, and 4 patients, who were simulated in both supine and prone position for XRT, were contoured. Dose to the heart and lung were calculated for all potential dwell locations within the contoured breast for a range of potential dwell times. Summary volume and dose metrics were calculated for heart and lung as function of minimum distance (dmin) to the normal structures. The distribution of minimum distances was then compared for the prone and supine patients. Results: Dose metrics such as the D10cc were patient specific and not well suited to parameterization. Volume metrics such as V10Gy tend to have similar behavior and may be characterized as a function of dmin. The characterization provides a measure of the normal tissue dose parameters that are achievable as a function of dmin. While prone position shift the distribution of lung to breast distances towards greater value, the distribution of heart to breast distances is shifted to smaller distances. Conclusion: Characteristic curves of the achievable volume metrics as a function of minimum distance from implant to normal structures are presented. These curves may be helpful in the decision to use APBI brachytherapy based on the location of the cavity. The choice of treatment position affects the distribution of breast tissue, though the effect on distance to heart and lung differs.

SU‐FF‐T‐48: Dosimetric Feasibility of Using Low Energy Sources in Multi‐Lumen Device for Partial Breast Brachytherapy

Purpose: To evaluate the dosimetric feasibility of using low energy sources (Cs‐131, I‐125, Pd‐103) in the multi‐lumen device for partial breast brachytherapy. The sources are placed into the device for multiple days until the desired dose is achieved, then withdrawn with the device. This outpatient procedure only requires two visits, one for source placement and another for device withdrawal. Method: A 10‐1 SAVI device was fully expanded, CT‐scanned and imported into VariSeed. Cavity, PTV (cavity + 1cm margin) and PTV_eval (PTV − cavity) were created. The same type and activity of seeds were added into the multi‐lumen device to cover the PTV_eval and seed activity was adjusted to achieve a nominal dose (50Gy in one half‐life of source). Different seed types and distributions were tested. Oncentra Brachy and IPSA optimization was used to generate a HDR plan for comparison. Dosimetric parameters (D90, V100, V150, and V200 of PTV_eval) and skin dose were compared. Results: D90, V100, V150, and V200 of PTV_eval of HDR plan are 107%, 97%, 52cc, and 24cc. The most comparable LDR plan is from a non‐uniform distributed 90 3.2U Cs‐131 source, which gives 102%, 92%, 52cc, and 26cc. Skin dose is lower than the HDR plan by ∼10% of the prescription dose from 0.5 ∼ 5 cm away from the PTV edge. With the comparable coverage, I‐125 gives slightly higher V150 and V200 (56cc and 30cc, respectively), while Pd‐103 gives much higher V150 and V200 (66cc and 46cc respectively). Conclusion: Cs‐131 is the best choice among the 3 commercially available low energy sources. It can provide adequate target coverage and similar dose homogeneity compared to HDR dosimetry in reasonable days (10 days). The faster dose fall‐off of the low energy sources give it advantage of less dose to the surrounding healthy tissues including skin, heart, and lung.

SU-FF-T-68: On the Dosimetric Differences Between Single Dwell and Multiple-Dwell Accelerated Partial Breast Brachytherapy Plans Delivered with a Single Catheter Spherical Balloon

Purpose: To compare single and multiple‐dwell dose distributions in patients treated with Mammosite (Cytyc Corp., Marlborough, MA) spherical balloons. Methods and Materials: 11 patients from our clinical data base were chosen. For each patient four treatment plans were generated: single dwell centered within the balloon, two, three and four dwells spaced uniformly along the catheter. Plans were generated with the Plato treatment planning system ver. 14.3.5 (Nucletron B.V., TH Veenendaal, The Netherlands) and imported into the Pinnacle3 planning system ver. 8.0h (Phillips Electronics N.V., Eindhoven, The Netherlands) for analysis. DVHs for the PTV, skin and ribs were computed. ANOVA from Matlab® (The Mathworks Inc., Natick, MA) was employed to detect differences in coverage of the 90%, 95%, 100%, 150% and 200% for the PTV, as well as differences in the 100 cGy, 125 cGy and 145 cGy doses to the skin and ribs. Dose difference DVHs were generated for each critical structure to illustrate any differences in the four planning methods. Results: The PTV DVH exhibited no significant difference amongst the four planning methods. The mean coverage of the 90%, 95%, 100%, 150% and 200% in the PTV showed no statistical difference amongst the four planning methods (p=0.8535, 0.6848, 0.4048, 0.7181, 0.6568). However, significant differences in skin doses (100 cGy and 125 cGy) were exhibited (p=0.0054, 0.0269). The single dwell method resulted in a higher percentage of skin receiving 100 cGy and 125 cGy (30% and 32% respectively). Significant differences of the 125 cGy and 145 cGy dose to the rib were also seen. (p=0.0582, 0.0841) The single dwell method resulted in a higher percentage of rib receiving 125 cGy and 145 cGy (29% and 26% respectively). Conclusions: Single and multiple dwell plans can provide similar PTV coverage. However, single dwell plans exhibit higher doses to the skin and ribs.

Partial Breast Brachytherapy as the Primary Treatment for Breast Cancer Diagnosed After Mantle Radiation Therapy for Hodgkin's Disease

Mastectomy is the most widely accepted treatment for managing breast cancer in patients who have previously received mantle radiation therapy (RT). With accumulating evidence supporting partial breast irradiation, we treated newly diagnosed breast cancer among lymphoma survivors who had history of RT with lumpectomy and breast brachytherapy. Five patients, with history of Hodgkin disease (HD) underwent lumpectomy and sentinel lymphadenectomy +/- axillary dissection followed by low dose rate Ir-192 interstitial brachytherapy. A multicatheter technique was used and all patients received 45 Gy to the target volume over 4 to 5 day time interval. Adjuvant systemic therapy when indicated was administered after completion of brachytherapy. The median time from the treatment of the HD to the diagnosis of breast cancer was 242 months (range: 68-322 months). The median T-size of the invasive breast cancer is 0.7 cm. The range of follow up after brachytherapy is 5 to 67 months. All 5 patients have an intact breast and are without evidence of relapse. No patients developed an infection. No skin toxicity > or =grade 2 was observed. All patients have an excellent cosmetic result. No excessive fibrosis or necrosis has been observed. The preliminary experience using partial breast brachytherapy (PBB) in patients with previous history of mantle RT suggests low complication rates, and acceptable cosmetic results. The excellent local control and freedom from mastectomy for local recurrence warrants further investigation to establish brachytherapy as an acceptable alternative to mastectomy for early stage breast cancer among HD survivors with history of prior RT.

What is the optimal insertion angle of MammoSite® balloon in partial breast brachytherapy? A dosimetric point of view

What is the optimal insertion angle of MammoSite® balloon in partial breast brachytherapy? A dosimetric point of view

A comparison study of technique, limitations and clinical outcome of MammoSite® vs. SAVI for partial breast brachytherapy

A comparison study of technique, limitations and clinical outcome of MammoSite® vs. SAVI for partial breast brachytherapy

A dosimetric comparison of AccuBoost® noninvasive partial breast brachytherapy to electron beam tumor bed boost and 3-D conformal accelerated partial breast irradiation

A dosimetric comparison of AccuBoost® noninvasive partial breast brachytherapy to electron beam tumor bed boost and 3-D conformal accelerated partial breast irradiation

Dose volume histogram analysis of normal structures associated with accelerated partial breast irradiation delivered by high dose rate brachytherapy and comparison with whole breast external beam radiotherapy fields

PurposeTo assess the radiation dose delivered to the heart and ipsilateral lung during accelerated partial breast brachytherapy using a MammoSite™ applicator and compare to those produced by whole breast external beam radiotherapy (WBRT).Materials and methodsDosimetric analysis was conducted on patients receiving MammoSite breast brachytherapy following conservative surgery for invasive ductal carcinoma. Cardiac dose was evaluated for patients with left breast tumors with a CT scan encompassing the entire heart. Lung dose was evaluated for patients in whom the entire lung was scanned. The prescription dose of 3400 cGy was 1 cm from the balloon surface. MammoSite dosimetry was compared to simulated WBRT fields with and without radiobiological correction for the effects of dose and fractionation. Dose parameters such as the volume of the structure receiving 10 Gy or more (V10) and the dose received by 20 cc of the structure (D20), were calculated as well as the maximum and mean doses received.ResultsFifteen patients were studied, five had complete lung data and six had left-sided tumors with complete cardiac data. Ipsilateral lung volumes ranged from 925–1380 cc. Cardiac volumes ranged from 337–551 cc. MammoSite resulted in a significantly lower percentage lung V30 and lung and cardiac V20 than the WBRT fields, with and without radiobiological correction.ConclusionThis study gives low values for incidental radiation received by the heart and ipsilateral lung using the MammoSite applicator. The volume of heart and lung irradiated to clinically significant levels was significantly lower with the MammoSite applicator than using simulated WBRT fields of the same CT data sets.Trial registrationDana Farber Trial Registry number 03-179

Multicatheter hybrid breast brachytherapy: A potential alternative for patients with inadequate skin distance

Purpose The purpose of this study was to determine whether the ClearPath (CP) multicatheter hybrid device was able to achieve acceptable dosimetry in patients in whom the proximity of the breast surgical cavity to the skin precluded treatment with intracavitary MammoSite (MS) brachytherapy. Methods and materials The study consisted of 11 patients who had the MS catheter placed and who were subsequently not treated due to inadequate skin distance. A phantom scan of the CP multicatheter hybrid device was superimposed on the MS CT scan and a dosimetric comparison was performed. Results The median MS balloon size, diameter, and minimum skin distance were 40 cc, 4.1 cm, and 5 mm, respectively. The D 90, V 100, V 150, and V 200 with MS vs. CP were 95.29% vs. 97.06%, 88.8% vs. 91.3%, 35.7% vs. 38.0%, and 9.4% vs. 9.6%, respectively. The median maximum skin dose was 5.5 Gy vs. 3.9 Gy ( p <.0001). The median dose homogeneity index (DHI) was 0.60 vs. 0.59 ( p = .09). The median maximum rib, heart, and lung dose were 2.17 Gy vs. 2.18 Gy, 2.17 Gy vs. 2.18 Gy, and 0.50 Gy vs. 0.56 Gy, respectively. Conclusion The hybrid CP catheter reduced the skin dose significantly without compromising the planning target volume coverage, DHI, or dose to other critical organs. The use of this device has the potential to increase the applicability of accelerated partial breast brachytherapy (APBI) in patients with a surgical cavity close to skin compared with balloon brachytherapy.

Dosimetric Comparison between Single-lumen Balloon (MammoSite) and Multi-lumen Balloon (Contura) in Partial Breast Brachytherapy

Single-lumen balloon device (MammoSite) has been widely used in the partial breast HDR brachytherapy after lumpectomy for early-stage breast cancer. Recently a multi-lumen balloon device (Contura) has become available, which has 5 fixed lumens in the shaft: one centered and four offset by 5 mm. In this study, we report the dosimetric comparison between treatment plans using single lumen and those using multi lumens.