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Dosimetric Analysis and Comparison of Interstitial HDR Brachytherapy, IMRT, 3DCRT and Electron Beam Therapy as Boost Modalities After Whole Breast Radiation in Breast Conservation Therapy
Abstracts / Brachytherapy 10 (2011) S14eS101 Results: The percentage of patients with good/excellent cosmesis at 6 months (n 5 39) was 92.3%, at 12 months (n 5 29) was 100%, at 24 months (n 5 16) was 87.5% and beyond 27 months up to 65 months of followup (n 5 24) was 95.8%. Median balloon to skin spacing was 10.7 mm (range, 3.9-36.4). The median percent of PD that 10 ccm of skin volume received was 41% (n 5 59). Dosimetric analysis showed no definitive association with comestic outcome. Two (2.7%) ipsilateral breast tumor recurrences occurred at 18.5 and 38.8 months after treatment. One (1.4%) patient had a suspicious mammogram with recommendation for biopsy, but secondary to the patient’s comorbidities she was deemed too high risk for a surgical biopsy and no tissue results were obtained. One (1.4%) patient developed spinal lesions consistent with metastatic disease at 41.8 months after treatment, but at present no tissue diagnosis has been made to determine if this is a distant breast cancer recurrence or other primary. Of note, of the eleven patients receiving external beam radiation subsequent to APBI none had breast cancer recurrence (n 5 11) and those who had followup of at least six months (n 5 9) had good/excellent cosmesis.
Followup visit in months
n
Good/excellent cosmesis
Percentage (%)
6 12 18 24 beyond 27
39 29 21 16 24
36 29 19 14 23
92.3 100 90.5 87.5 95.8
S47
Vs 53% Vs 46% for HDR, IMRT, 3DCRT, EBT, respectively. Dose to other organ at risk was within tolerance limit in all the methods. Conclusions: HDR brachytherapy as a boost modality in BCT is most conformal technique and has the potential for improve cosmesis by virtue of lesser dose to ipsilateral breast due to lack of PTV margin.
PD17 Inter-Fraction Accumulation of Seroma During Accelerated Partial Breast Irradiation: Preliminary Results of a Prospective Study Aashish D. Bhatt, MD1, John B. Crew, MD1, Geetika A. Bhatt, MBBS2, Robert R. Johnson, MD1, Keith T. Sowards, MS1, Anthony E. Dragun, MD1. 1Radiation Oncology, University of Louisville, Louisville, KY; 2 Kasturba Medical College, Manipal University, Mangalore, Karnataka, India. Purpose: To quantify and characterize the process of seroma accumulation during APBI using multi-catheter balloon brachytherapy. Materials and Methods: We prospectively followed 22 breast conservation patients treated at our institution with accelerated partial breast irradiation (APBI) from time of surgical placement of the brachytherapy catheter to completion of therapy. All patients were treated using the ConturaÔ Multi-lumen Brachytherapy (MLB) catheter using standard techniques to a total dose of 34 Gy in 10 fractions delivered over 5 treatment days. Serial aspirations of the vacuum port of the ConturaÔ catheter were performed at the time of initial CT simulation and then prior to each fraction.
Conclusions: The Contura multilumen and MammoSite balloon catheters provide good local control and good/excellent cosmetic results in early stage breast cancer treatments. Further dosimetric analysis is needed to determine the effect on cosmesis. The two patients with tissue proven local recurrence were ER/PR (-). Regarding the two patients without tissue proven recurrence, the patient with possible metastatic disease was ER/PR (-) and the patient with a suspicious mammogram was ER/PR (þ), but had Stage II disease. ER/PR negativity and more advanced stage at diagnosis are poor prognostic features. Future research needs to be done to provide better treatment strategies for these higher risk patients.
PD16 Dosimetric Analysis and Comparison of Interstitial HDR Brachytherapy, IMRT, 3DCRT and Electron Beam Therapy as Boost Modalities After Whole Breast Radiation in Breast Conservation Therapy Suman Mallik, MD, DNB, Kaustav Talapatra, MD, Dayananda Sharma, MSc, Vaibhab Mahtre, MSc, Malhotra Singh, MSc. Radiation Oncology, Kokilaben Dhirubhai Ambani Hospital and Research Centre, Mumbai, Maharashtra, India. Purpose: We compared the dose conformity to the target, dose to the organs at risk and high dose region to ipsilateral breast tissue of four radiation modalities HDR brachytherapy, 3DCRT, IMRT, Electron beam therapy (EBT) to deliver boost to tumor bed region after whole breast radiotherapy in breast conservative therapy (BCT). Materials and Methods: Complimentary virtual interstitial HDR brachytherapy, IMRT, 3DCRT, EBT plans were generated in ten successive patients with breast carcinoma who had tumor at suitable location for HDR brachytherapy and were treated by whole breast radiotherapy followed by electron or 3DCRT boost. All patients received 45 Gy in 25 fractions whole breast radiotherapy. Boost plans were generated for 15 Gy in 6 fractions. All four plans were compared based on conformity, dose to organ at risk, dose to the ipsilateral breast. Results: Mean dose higher in HDR brachytherapy plans compared to others with maximum heterogeneity. Conformity index was maximum for HDR brachytherapy (0.81) followed by IMRT (0.76) and was worst by electron beam therapy (0.32). Mean V50 Gy of ipsilateral breast was 26% Vs 37%
The volume and characteristics of fluid drawn with each aspiration were recorded and tracked over time. Statistics, including univariate and multivariate analysis, were performed to evaluate various factors hypothesized to contribute to seroma formation. Results: Median patient age was 59.5 yrs and median body mass index (BMI) was 31. Median volume of the surgical specimen was 62.4 cc. Reexcision and/or repeat operation was performed in 32% of the patients. Median time from initial breast conservation surgery to placement of the ConturaÔ catheter was 18.5 days. Median catheter balloon volume was 36.5 cc. Peri-catheter seroma, typically scant with a median volume of 0.75 cc, was noted in 91% of patients at CT simulation and was aspirated in all patients to improve balloon conformality to the resection cavity. A total of 203 aspirations were performed pre- and on-treatment with a median aspirated seroma volume of 4.05 cc. Seroma was described as serosanguineous in most instances. There was no significant difference in the quantity aspirated prior to the morning fraction, afternoon fraction, or following a 2-day weekend break. There was no significant correlation between the volume of seroma and histology (invasive vs. DCIS), quadrant of location, BMI, re-excision or re-operation, days from BCS to balloon placement, or the volume of specimen removed. Radiation treatment factors including balloon volume, balloon to skin distance, and
Followup visit in months
n
Good/excellent cosmesis
Percentage (%)
6 12 18 24 beyond 27
39 29 21 16 24
36 29 19 14 23
92.3 100 90.5 87.5 95.8
S47
Vs 53% Vs 46% for HDR, IMRT, 3DCRT, EBT, respectively. Dose to other organ at risk was within tolerance limit in all the methods. Conclusions: HDR brachytherapy as a boost modality in BCT is most conformal technique and has the potential for improve cosmesis by virtue of lesser dose to ipsilateral breast due to lack of PTV margin.
PD17 Inter-Fraction Accumulation of Seroma During Accelerated Partial Breast Irradiation: Preliminary Results of a Prospective Study Aashish D. Bhatt, MD1, John B. Crew, MD1, Geetika A. Bhatt, MBBS2, Robert R. Johnson, MD1, Keith T. Sowards, MS1, Anthony E. Dragun, MD1. 1Radiation Oncology, University of Louisville, Louisville, KY; 2 Kasturba Medical College, Manipal University, Mangalore, Karnataka, India. Purpose: To quantify and characterize the process of seroma accumulation during APBI using multi-catheter balloon brachytherapy. Materials and Methods: We prospectively followed 22 breast conservation patients treated at our institution with accelerated partial breast irradiation (APBI) from time of surgical placement of the brachytherapy catheter to completion of therapy. All patients were treated using the ConturaÔ Multi-lumen Brachytherapy (MLB) catheter using standard techniques to a total dose of 34 Gy in 10 fractions delivered over 5 treatment days. Serial aspirations of the vacuum port of the ConturaÔ catheter were performed at the time of initial CT simulation and then prior to each fraction.
Conclusions: The Contura multilumen and MammoSite balloon catheters provide good local control and good/excellent cosmetic results in early stage breast cancer treatments. Further dosimetric analysis is needed to determine the effect on cosmesis. The two patients with tissue proven local recurrence were ER/PR (-). Regarding the two patients without tissue proven recurrence, the patient with possible metastatic disease was ER/PR (-) and the patient with a suspicious mammogram was ER/PR (þ), but had Stage II disease. ER/PR negativity and more advanced stage at diagnosis are poor prognostic features. Future research needs to be done to provide better treatment strategies for these higher risk patients.
PD16 Dosimetric Analysis and Comparison of Interstitial HDR Brachytherapy, IMRT, 3DCRT and Electron Beam Therapy as Boost Modalities After Whole Breast Radiation in Breast Conservation Therapy Suman Mallik, MD, DNB, Kaustav Talapatra, MD, Dayananda Sharma, MSc, Vaibhab Mahtre, MSc, Malhotra Singh, MSc. Radiation Oncology, Kokilaben Dhirubhai Ambani Hospital and Research Centre, Mumbai, Maharashtra, India. Purpose: We compared the dose conformity to the target, dose to the organs at risk and high dose region to ipsilateral breast tissue of four radiation modalities HDR brachytherapy, 3DCRT, IMRT, Electron beam therapy (EBT) to deliver boost to tumor bed region after whole breast radiotherapy in breast conservative therapy (BCT). Materials and Methods: Complimentary virtual interstitial HDR brachytherapy, IMRT, 3DCRT, EBT plans were generated in ten successive patients with breast carcinoma who had tumor at suitable location for HDR brachytherapy and were treated by whole breast radiotherapy followed by electron or 3DCRT boost. All patients received 45 Gy in 25 fractions whole breast radiotherapy. Boost plans were generated for 15 Gy in 6 fractions. All four plans were compared based on conformity, dose to organ at risk, dose to the ipsilateral breast. Results: Mean dose higher in HDR brachytherapy plans compared to others with maximum heterogeneity. Conformity index was maximum for HDR brachytherapy (0.81) followed by IMRT (0.76) and was worst by electron beam therapy (0.32). Mean V50 Gy of ipsilateral breast was 26% Vs 37%
The volume and characteristics of fluid drawn with each aspiration were recorded and tracked over time. Statistics, including univariate and multivariate analysis, were performed to evaluate various factors hypothesized to contribute to seroma formation. Results: Median patient age was 59.5 yrs and median body mass index (BMI) was 31. Median volume of the surgical specimen was 62.4 cc. Reexcision and/or repeat operation was performed in 32% of the patients. Median time from initial breast conservation surgery to placement of the ConturaÔ catheter was 18.5 days. Median catheter balloon volume was 36.5 cc. Peri-catheter seroma, typically scant with a median volume of 0.75 cc, was noted in 91% of patients at CT simulation and was aspirated in all patients to improve balloon conformality to the resection cavity. A total of 203 aspirations were performed pre- and on-treatment with a median aspirated seroma volume of 4.05 cc. Seroma was described as serosanguineous in most instances. There was no significant difference in the quantity aspirated prior to the morning fraction, afternoon fraction, or following a 2-day weekend break. There was no significant correlation between the volume of seroma and histology (invasive vs. DCIS), quadrant of location, BMI, re-excision or re-operation, days from BCS to balloon placement, or the volume of specimen removed. Radiation treatment factors including balloon volume, balloon to skin distance, and