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Sensitivity of Tangential Verification Films to Treatment Set-up Deviations for Patients Receiving Breast Radiation Therapy
S256
I. J. Radiation Oncology
● Biology ● Physics
Volume 63, Number 2, Supplement, 2005
implant. The cosmetic outcome following radiation therapy (RT) has been previously reported as inferior. This study was undertaken to evaluate our experience regarding the cosmetic outcome in this group of patients. Materials/Methods: Between 1994 and 2004, we retrospectively reviewed the records of 26 breast cancer patients with previously augmented breasts who were treated with breast conserving surgery and radiation therapy at Mayo Clinic. All patients had their implants placed prior to their breast cancer diagnosis. All 26 patients were treated with lumpectomy, sentinel lymph node biopsies and/or axillary dissections followed by RT. None of the patients had a mastectomy with reconstruction. Fourteen patients had saline implants, 9 patients had silicone implants and in 3 patients the type of implant was unknown. Cosmetic outcome was judged by the Baker classification grading system (grade 1– 4) for capsular contracture. Each patient received a score prior to radiotherapy and post-radiotherapy. Each patient was treated with multi-plane CT-based treatment planning. Median dose to the whole breast was 48.6 Gy (range, 48 –50.4 Gy) and the mean total dose of radiation was 60.6 Gy (range, 50.4 – 61.4 Gy). Results: The median follow-up for all patients was 36 months (range, 1.4 –120). Twenty-two patients (84.6%) had a favorable cosmetic outcome with a Baker grade of 1 or 2 following radiation therapy. Only 4 (15.4%) patients had an unfavorable cosmetic outcome (Baker grades 3 or 4). These four patients subsequently had their implants exchanged and following this operation had a final Baker grade of 1. The mean Baker grade prior to breast conservation therapy was 1.22 and the mean Baker score following radiation therapy at the time of last follow-up was 1.66. There were no local failures and no deaths. Conclusions: Breast conservation therapy is a reasonable treatment option for women with breast cancer who have breast implants in place. The cosmetic outcome following radiation therapy is generally favorable. This treatment strategy is likely to be favored by the population of patients who were interested enough in the appearance of their breasts to have undergone prior augmentation surgery.
2043
Sensitivity of Tangential Verification Films to Treatment Set-up Deviations for Patients Receiving Breast Radiation Therapy
V.V. Patenaude,1 D. Wells,1,3 C. Golling,1 D. Sayers,1 L. McGovern,1 E. Wai1,2 Radiation Therapy, BCCA Vancouver Island, Victoria, BC, Canada, 2University of British Columbia, Vancouver, BC, Canada, 3University of Victoria, Victoria, BC, Canada 1
Purpose/Objective: Electronic portal images (EPIs) matched to CT-planned digitally reconstructed radiographs (DRRs) are routinely utilized at this cancer facility to verify treatment set-ups for patients undergoing tangential breast irradiation. This study investigated how sensitive tangential portal view verification films alone are to clinically significant set-up deviations to evaluate current practice Materials/Methods: 5 patients with left sided breast cancer and 5 patients with right sided breast cancer were randomly selected from our centers radiation therapy database. This cohort of 10 patients had standard DRRs constructed from the original treatment plans tangential fields. Baseline values were calculated from each DRR for 4 parameters (metrics): central lung distance (CLD), superior lung distance (SLD), inferior breast distance (IBD) and central breast distance (CBD). 68 specific moves were made to the plans isocenter for each patient to simulate setup deviations in the anterior/posterior (A/P), superior/inferior (S/I) and medial/lateral (M/L) directions. In addition patient rotation deviations were simulated with clockwise (CW) or counterclockwise (CCW) beam angle rotation. New DRRs which would correspond to the EPIs were generated and the same metrics were analyzed to determine if moves made to the isocenter resulted in measurable and correlating set-up variations on DRR. Sensitivity Factors (SF) defined as change in a given metric divided by actual setup deviation was calculated for each parameter. The ideal metric of SF⫽1 means that isocenter movement is perfectly correlated with the corresponding distance on the DRR. A SF⫽0 would indicate no correlation between isocenter move and measured metric on corresponding DRR. Results: Measured metrics were similar for both right and left sided patients. CBD and CLD measurements were highly correlated with high A/P sensitivity (SF⬎0.8). All other metrics were below 0.5. SFs for SLD showed high standard deviations, making this metric unreliable. SFs for IBD approached 1 in the S/I direction, and were ⬍ 0.3 in all other directions. SFs for rotational movements approached 0 for all measurements. SFs for combination setup deviations were more variable and complex. Conclusions: Tangential DRRs were sensitive to A/P and S/I set-up variations, but there were no metrics sensitive to M/L or rotational variations. Certain combination moves also indicated low SFs indicating that there is a poor correlation of actual setup deviation to any measurable film deviations. Use of tangential field EPIs alone are inadequate to detect clinically relevant rotational or M/L set-up deviations in women treated with tangential breast irradiation. It is suggested that additional means, e.g. orthogonal EPIs, should be considered to ensure adequate verification of treatment set-up.
2044
Transcription Factor STAT3, Mediates Expression of Survivin Protein, as Therapeutic Target for Radiation Sensitization in Breast Cancer
K. Kim,1 C. Cao,1 E.T. Shinohara,1 K.R. Sekhar,1 Z. Ren,2 Q. Cai,2 W. Zheng,2 B. Lu1 Department of Radiation Oncology, Vanderbilt University, Nashville, TN, 2Department of Medicine and Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN 1
Purpose/Objective: Signal transducer and activator of transcription 3 (STAT3), which was identified as an interleukin-6activated transcription factor, transduces signaling from the cytoplasm to the nucleus and then activates expression of many targeted genes. It plays an important role in controlling cell transformation and oncogenesis. In previous studies, we found that radiation (3Gy) significantly reduced both protein and mRNA levels of survivin in human umbilical vein endothelial cells (HUVECs), but not in tumor cell lines. In this study, we examined whether Stat3 mediates survivin expression following irradiation in HUVECs and breast cancer cells. Materials/Methods: The infection was as described previously (Song et at, 2004). Cells were plated into 10 cm culture dish 2days prior to infection. The cells were infected with adenovirus vector (PAdCMVpLPA(-)Xoxp-SSP), adenovirus Stat3-C, or
I. J. Radiation Oncology
● Biology ● Physics
Volume 63, Number 2, Supplement, 2005
implant. The cosmetic outcome following radiation therapy (RT) has been previously reported as inferior. This study was undertaken to evaluate our experience regarding the cosmetic outcome in this group of patients. Materials/Methods: Between 1994 and 2004, we retrospectively reviewed the records of 26 breast cancer patients with previously augmented breasts who were treated with breast conserving surgery and radiation therapy at Mayo Clinic. All patients had their implants placed prior to their breast cancer diagnosis. All 26 patients were treated with lumpectomy, sentinel lymph node biopsies and/or axillary dissections followed by RT. None of the patients had a mastectomy with reconstruction. Fourteen patients had saline implants, 9 patients had silicone implants and in 3 patients the type of implant was unknown. Cosmetic outcome was judged by the Baker classification grading system (grade 1– 4) for capsular contracture. Each patient received a score prior to radiotherapy and post-radiotherapy. Each patient was treated with multi-plane CT-based treatment planning. Median dose to the whole breast was 48.6 Gy (range, 48 –50.4 Gy) and the mean total dose of radiation was 60.6 Gy (range, 50.4 – 61.4 Gy). Results: The median follow-up for all patients was 36 months (range, 1.4 –120). Twenty-two patients (84.6%) had a favorable cosmetic outcome with a Baker grade of 1 or 2 following radiation therapy. Only 4 (15.4%) patients had an unfavorable cosmetic outcome (Baker grades 3 or 4). These four patients subsequently had their implants exchanged and following this operation had a final Baker grade of 1. The mean Baker grade prior to breast conservation therapy was 1.22 and the mean Baker score following radiation therapy at the time of last follow-up was 1.66. There were no local failures and no deaths. Conclusions: Breast conservation therapy is a reasonable treatment option for women with breast cancer who have breast implants in place. The cosmetic outcome following radiation therapy is generally favorable. This treatment strategy is likely to be favored by the population of patients who were interested enough in the appearance of their breasts to have undergone prior augmentation surgery.
2043
Sensitivity of Tangential Verification Films to Treatment Set-up Deviations for Patients Receiving Breast Radiation Therapy
V.V. Patenaude,1 D. Wells,1,3 C. Golling,1 D. Sayers,1 L. McGovern,1 E. Wai1,2 Radiation Therapy, BCCA Vancouver Island, Victoria, BC, Canada, 2University of British Columbia, Vancouver, BC, Canada, 3University of Victoria, Victoria, BC, Canada 1
Purpose/Objective: Electronic portal images (EPIs) matched to CT-planned digitally reconstructed radiographs (DRRs) are routinely utilized at this cancer facility to verify treatment set-ups for patients undergoing tangential breast irradiation. This study investigated how sensitive tangential portal view verification films alone are to clinically significant set-up deviations to evaluate current practice Materials/Methods: 5 patients with left sided breast cancer and 5 patients with right sided breast cancer were randomly selected from our centers radiation therapy database. This cohort of 10 patients had standard DRRs constructed from the original treatment plans tangential fields. Baseline values were calculated from each DRR for 4 parameters (metrics): central lung distance (CLD), superior lung distance (SLD), inferior breast distance (IBD) and central breast distance (CBD). 68 specific moves were made to the plans isocenter for each patient to simulate setup deviations in the anterior/posterior (A/P), superior/inferior (S/I) and medial/lateral (M/L) directions. In addition patient rotation deviations were simulated with clockwise (CW) or counterclockwise (CCW) beam angle rotation. New DRRs which would correspond to the EPIs were generated and the same metrics were analyzed to determine if moves made to the isocenter resulted in measurable and correlating set-up variations on DRR. Sensitivity Factors (SF) defined as change in a given metric divided by actual setup deviation was calculated for each parameter. The ideal metric of SF⫽1 means that isocenter movement is perfectly correlated with the corresponding distance on the DRR. A SF⫽0 would indicate no correlation between isocenter move and measured metric on corresponding DRR. Results: Measured metrics were similar for both right and left sided patients. CBD and CLD measurements were highly correlated with high A/P sensitivity (SF⬎0.8). All other metrics were below 0.5. SFs for SLD showed high standard deviations, making this metric unreliable. SFs for IBD approached 1 in the S/I direction, and were ⬍ 0.3 in all other directions. SFs for rotational movements approached 0 for all measurements. SFs for combination setup deviations were more variable and complex. Conclusions: Tangential DRRs were sensitive to A/P and S/I set-up variations, but there were no metrics sensitive to M/L or rotational variations. Certain combination moves also indicated low SFs indicating that there is a poor correlation of actual setup deviation to any measurable film deviations. Use of tangential field EPIs alone are inadequate to detect clinically relevant rotational or M/L set-up deviations in women treated with tangential breast irradiation. It is suggested that additional means, e.g. orthogonal EPIs, should be considered to ensure adequate verification of treatment set-up.
2044
Transcription Factor STAT3, Mediates Expression of Survivin Protein, as Therapeutic Target for Radiation Sensitization in Breast Cancer
K. Kim,1 C. Cao,1 E.T. Shinohara,1 K.R. Sekhar,1 Z. Ren,2 Q. Cai,2 W. Zheng,2 B. Lu1 Department of Radiation Oncology, Vanderbilt University, Nashville, TN, 2Department of Medicine and Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN 1
Purpose/Objective: Signal transducer and activator of transcription 3 (STAT3), which was identified as an interleukin-6activated transcription factor, transduces signaling from the cytoplasm to the nucleus and then activates expression of many targeted genes. It plays an important role in controlling cell transformation and oncogenesis. In previous studies, we found that radiation (3Gy) significantly reduced both protein and mRNA levels of survivin in human umbilical vein endothelial cells (HUVECs), but not in tumor cell lines. In this study, we examined whether Stat3 mediates survivin expression following irradiation in HUVECs and breast cancer cells. Materials/Methods: The infection was as described previously (Song et at, 2004). Cells were plated into 10 cm culture dish 2days prior to infection. The cells were infected with adenovirus vector (PAdCMVpLPA(-)Xoxp-SSP), adenovirus Stat3-C, or