Purpose/Objective(s)Image-guided radiation therapy (IGRT) using fiducial markers (FM) or cone beam CT (CBCT) is the preferred method in delivering RT for prostate cancer (PC) enabling precise targeting and dose escalation. These techniques should enable reduced CTV to PTV margins resulting in lower toxicity. We applied the Van Herk formula to calculate the margin for PTV of prostate using CBCT or FM.Materials/MethodsTwenty patients with low, intermediate or high risk PC received IGRT (VMAT) to a dose of 74Gy/37f, 60Gy/20f or 57Gy/19f. Three gold FM were implanted prior to treatment. Patients were planned and treated with rectal balloon (RB). CBCT was performed on day 1 to 3, then once every week. KV-image pairs (kV/kV) were used on all other days. For 10 patients CBCT was performed after each fraction to assess intra-fractional motion. Contouring of the prostate (P) for low risk and of the prostate/seminal vesicles (PSV) for intermediate/high risk PC was performed independently by 3 clinicians and mean differences in vertical, lateral and longitudinal directions between the intersections and the unions of the three contours were assessed. The Van Herk formula M = 2.5Σ + 0.7σ3 was used for PTV margin calculation, where Σ represents the systematic and σ the random error. We calculated the systematic errors for intra-fractional motion, contouring as well as setup using CBCT, kV/kV and FM referring to prostate position in the CBCT and random errors for intra-fractional motion and patient setup.ResultsCalculated PTV margins were 6.1 mm vertically, 7.1 mm longitudinally and 4.4 mm laterally for contouring and intra-fractional but not setup errors. Systematic error for contouring was more influential than intra-fractional motion (0.9-1.4mm) and more pronounced in intermediate/high risk (2.5-3.2mm) than in low risk PC (1.3-2.1mm). Including setup errors, enlargement was least for CBCT and kV/kV-imaging using FM: +0.4-0.6mm (P) / +2.0-2.3mm (PSV) vertically, +0.1-0.7mm (P) / +2.5-2.9mm (PSV) longitudinally and +0.3mm (P) / +3.0-3.1mm (PSV) laterally. Higher increases were noticed for bone matching: +1.8-2.0mm (P) / +2.2-2.4mm (PSV) vertically, +1.4-1.5mm (P) / +3.6mm (PSV) longitudinally and +0.4-0.7mm (P) / +3.0-3.3mm (PSV) laterally. Largest increases were found for rectal balloon matching: +1.3-1.6mm (P) / +2.8-3.0mm (PSV) vertically, +0.9-4.5mm (P) / +3.1-6.2mm (PSV) longitudinally and +0.5-2.0mm (P) / +3.1-4.1mm (PSV) laterally.ConclusionCalculated PTV margins are comparable using either CBCT or kV/kV-imaging FM matching. The systematic error for contouring was more influential than intra-fractional motion. Margins for intermediate/high risk PC are notably larger than those for low risk PC due to seminal vesicles. Purpose/Objective(s)Image-guided radiation therapy (IGRT) using fiducial markers (FM) or cone beam CT (CBCT) is the preferred method in delivering RT for prostate cancer (PC) enabling precise targeting and dose escalation. These techniques should enable reduced CTV to PTV margins resulting in lower toxicity. We applied the Van Herk formula to calculate the margin for PTV of prostate using CBCT or FM. Image-guided radiation therapy (IGRT) using fiducial markers (FM) or cone beam CT (CBCT) is the preferred method in delivering RT for prostate cancer (PC) enabling precise targeting and dose escalation. These techniques should enable reduced CTV to PTV margins resulting in lower toxicity. We applied the Van Herk formula to calculate the margin for PTV of prostate using CBCT or FM. Materials/MethodsTwenty patients with low, intermediate or high risk PC received IGRT (VMAT) to a dose of 74Gy/37f, 60Gy/20f or 57Gy/19f. Three gold FM were implanted prior to treatment. Patients were planned and treated with rectal balloon (RB). CBCT was performed on day 1 to 3, then once every week. KV-image pairs (kV/kV) were used on all other days. For 10 patients CBCT was performed after each fraction to assess intra-fractional motion. Contouring of the prostate (P) for low risk and of the prostate/seminal vesicles (PSV) for intermediate/high risk PC was performed independently by 3 clinicians and mean differences in vertical, lateral and longitudinal directions between the intersections and the unions of the three contours were assessed. The Van Herk formula M = 2.5Σ + 0.7σ3 was used for PTV margin calculation, where Σ represents the systematic and σ the random error. We calculated the systematic errors for intra-fractional motion, contouring as well as setup using CBCT, kV/kV and FM referring to prostate position in the CBCT and random errors for intra-fractional motion and patient setup. Twenty patients with low, intermediate or high risk PC received IGRT (VMAT) to a dose of 74Gy/37f, 60Gy/20f or 57Gy/19f. Three gold FM were implanted prior to treatment. Patients were planned and treated with rectal balloon (RB). CBCT was performed on day 1 to 3, then once every week. KV-image pairs (kV/kV) were used on all other days. For 10 patients CBCT was performed after each fraction to assess intra-fractional motion. Contouring of the prostate (P) for low risk and of the prostate/seminal vesicles (PSV) for intermediate/high risk PC was performed independently by 3 clinicians and mean differences in vertical, lateral and longitudinal directions between the intersections and the unions of the three contours were assessed. The Van Herk formula M = 2.5Σ + 0.7σ3 was used for PTV margin calculation, where Σ represents the systematic and σ the random error. We calculated the systematic errors for intra-fractional motion, contouring as well as setup using CBCT, kV/kV and FM referring to prostate position in the CBCT and random errors for intra-fractional motion and patient setup. ResultsCalculated PTV margins were 6.1 mm vertically, 7.1 mm longitudinally and 4.4 mm laterally for contouring and intra-fractional but not setup errors. Systematic error for contouring was more influential than intra-fractional motion (0.9-1.4mm) and more pronounced in intermediate/high risk (2.5-3.2mm) than in low risk PC (1.3-2.1mm). Including setup errors, enlargement was least for CBCT and kV/kV-imaging using FM: +0.4-0.6mm (P) / +2.0-2.3mm (PSV) vertically, +0.1-0.7mm (P) / +2.5-2.9mm (PSV) longitudinally and +0.3mm (P) / +3.0-3.1mm (PSV) laterally. Higher increases were noticed for bone matching: +1.8-2.0mm (P) / +2.2-2.4mm (PSV) vertically, +1.4-1.5mm (P) / +3.6mm (PSV) longitudinally and +0.4-0.7mm (P) / +3.0-3.3mm (PSV) laterally. Largest increases were found for rectal balloon matching: +1.3-1.6mm (P) / +2.8-3.0mm (PSV) vertically, +0.9-4.5mm (P) / +3.1-6.2mm (PSV) longitudinally and +0.5-2.0mm (P) / +3.1-4.1mm (PSV) laterally. Calculated PTV margins were 6.1 mm vertically, 7.1 mm longitudinally and 4.4 mm laterally for contouring and intra-fractional but not setup errors. Systematic error for contouring was more influential than intra-fractional motion (0.9-1.4mm) and more pronounced in intermediate/high risk (2.5-3.2mm) than in low risk PC (1.3-2.1mm). Including setup errors, enlargement was least for CBCT and kV/kV-imaging using FM: +0.4-0.6mm (P) / +2.0-2.3mm (PSV) vertically, +0.1-0.7mm (P) / +2.5-2.9mm (PSV) longitudinally and +0.3mm (P) / +3.0-3.1mm (PSV) laterally. Higher increases were noticed for bone matching: +1.8-2.0mm (P) / +2.2-2.4mm (PSV) vertically, +1.4-1.5mm (P) / +3.6mm (PSV) longitudinally and +0.4-0.7mm (P) / +3.0-3.3mm (PSV) laterally. Largest increases were found for rectal balloon matching: +1.3-1.6mm (P) / +2.8-3.0mm (PSV) vertically, +0.9-4.5mm (P) / +3.1-6.2mm (PSV) longitudinally and +0.5-2.0mm (P) / +3.1-4.1mm (PSV) laterally. ConclusionCalculated PTV margins are comparable using either CBCT or kV/kV-imaging FM matching. The systematic error for contouring was more influential than intra-fractional motion. Margins for intermediate/high risk PC are notably larger than those for low risk PC due to seminal vesicles. Calculated PTV margins are comparable using either CBCT or kV/kV-imaging FM matching. The systematic error for contouring was more influential than intra-fractional motion. Margins for intermediate/high risk PC are notably larger than those for low risk PC due to seminal vesicles.

Purpose/Objective(s)Image-guided radiotherapy (IGRT) using fiducial markers (FM) or cone beam CT (CBCT) is the preferred method to deliver curative treatment for prostate cancer (PC) enabling precise targeting and dose escalation. These techniques should enable reduced CTV to PTV margins resulting in lower toxicity. There is little consensus defining which of these techniques should be applied.Materials/MethodsTwenty patients received IGRT (RapidArc) to a dose of 74Gy/37f, 60Gy/20f or 57Gy/19f. Three gold FM were implanted two weeks prior to treatment and all patients were planned and treated with rectal balloon (RB). CBCT was performed on treatment day 1 to 3, then once every week. KV-image pairs (kV/kV) were used on all other days. Additionally kV-image pairs and CBCT were performed on the same day in some patients. Online positioning of the isocenter was performed according to FM using CBCT or kV image pairs. Absolute isocenter shifts between tattoos and either FM, bony landmarks, RB or prostate tissue were measured using manual matching in offline review. In addition, relative shifts between matching techniques including FM - RB, FM - bony landmarks and bony landmarks - RB were measured.ResultsMean absolute isocenter shifts were 6.9mm ± 3.7 (kV/kV) and 6.1mm ± 3.4 (CBCT) for tattoos to FM and 6.2mm ± 3.4 (CBCT) for tattoos to prostate tissue. KV/kV matching for FM correlated well with CBCT matching for FM (R2 = 0.92). Mean relative shift for FM (kV/kV) - FM (CBCT) was 1.7mm ± 0.9. As expected, CBCT matching for FM correlated well with matching for prostate tissue (R2 = 0.922) with a mean relative shift of 1.3mm ± 1.1. However, CBCT matching for FM poorly correlated with matching for RB (R2 = 0.608) or bony landmarks (R2 = 0.617).Mean relative shifts for FM - RB, FM - bony landmarks and bony landmarks - RB were, 2.6mm ± 2.2, 2.6mm ± 2.3and 2.0mm ± 2.5 using CBCT compared to 4.9mm ± 2.8, 3.5mm ± 2.3 and 5.9mm ± 3.4 using kV/kV.ConclusionsIGRT in combination with either FM or CBRT has an equally high accuracy in the matching process of prostate tissue. FM in combination with kV-image pairs combines the advantages of a low imaging dose to the patient with a high precision setup equivalent to a soft tissue match. A reduction of daily setup errors can be achieved allowing reduction of CTV to PTV margins. RB is an unreliable substitute for prostate tissue localization. Purpose/Objective(s)Image-guided radiotherapy (IGRT) using fiducial markers (FM) or cone beam CT (CBCT) is the preferred method to deliver curative treatment for prostate cancer (PC) enabling precise targeting and dose escalation. These techniques should enable reduced CTV to PTV margins resulting in lower toxicity. There is little consensus defining which of these techniques should be applied. Image-guided radiotherapy (IGRT) using fiducial markers (FM) or cone beam CT (CBCT) is the preferred method to deliver curative treatment for prostate cancer (PC) enabling precise targeting and dose escalation. These techniques should enable reduced CTV to PTV margins resulting in lower toxicity. There is little consensus defining which of these techniques should be applied. Materials/MethodsTwenty patients received IGRT (RapidArc) to a dose of 74Gy/37f, 60Gy/20f or 57Gy/19f. Three gold FM were implanted two weeks prior to treatment and all patients were planned and treated with rectal balloon (RB). CBCT was performed on treatment day 1 to 3, then once every week. KV-image pairs (kV/kV) were used on all other days. Additionally kV-image pairs and CBCT were performed on the same day in some patients. Online positioning of the isocenter was performed according to FM using CBCT or kV image pairs. Absolute isocenter shifts between tattoos and either FM, bony landmarks, RB or prostate tissue were measured using manual matching in offline review. In addition, relative shifts between matching techniques including FM - RB, FM - bony landmarks and bony landmarks - RB were measured. Twenty patients received IGRT (RapidArc) to a dose of 74Gy/37f, 60Gy/20f or 57Gy/19f. Three gold FM were implanted two weeks prior to treatment and all patients were planned and treated with rectal balloon (RB). CBCT was performed on treatment day 1 to 3, then once every week. KV-image pairs (kV/kV) were used on all other days. Additionally kV-image pairs and CBCT were performed on the same day in some patients. Online positioning of the isocenter was performed according to FM using CBCT or kV image pairs. Absolute isocenter shifts between tattoos and either FM, bony landmarks, RB or prostate tissue were measured using manual matching in offline review. In addition, relative shifts between matching techniques including FM - RB, FM - bony landmarks and bony landmarks - RB were measured. ResultsMean absolute isocenter shifts were 6.9mm ± 3.7 (kV/kV) and 6.1mm ± 3.4 (CBCT) for tattoos to FM and 6.2mm ± 3.4 (CBCT) for tattoos to prostate tissue. KV/kV matching for FM correlated well with CBCT matching for FM (R2 = 0.92). Mean relative shift for FM (kV/kV) - FM (CBCT) was 1.7mm ± 0.9. As expected, CBCT matching for FM correlated well with matching for prostate tissue (R2 = 0.922) with a mean relative shift of 1.3mm ± 1.1. However, CBCT matching for FM poorly correlated with matching for RB (R2 = 0.608) or bony landmarks (R2 = 0.617).Mean relative shifts for FM - RB, FM - bony landmarks and bony landmarks - RB were, 2.6mm ± 2.2, 2.6mm ± 2.3and 2.0mm ± 2.5 using CBCT compared to 4.9mm ± 2.8, 3.5mm ± 2.3 and 5.9mm ± 3.4 using kV/kV. Mean absolute isocenter shifts were 6.9mm ± 3.7 (kV/kV) and 6.1mm ± 3.4 (CBCT) for tattoos to FM and 6.2mm ± 3.4 (CBCT) for tattoos to prostate tissue. KV/kV matching for FM correlated well with CBCT matching for FM (R2 = 0.92). Mean relative shift for FM (kV/kV) - FM (CBCT) was 1.7mm ± 0.9. As expected, CBCT matching for FM correlated well with matching for prostate tissue (R2 = 0.922) with a mean relative shift of 1.3mm ± 1.1. However, CBCT matching for FM poorly correlated with matching for RB (R2 = 0.608) or bony landmarks (R2 = 0.617).Mean relative shifts for FM - RB, FM - bony landmarks and bony landmarks - RB were, 2.6mm ± 2.2, 2.6mm ± 2.3and 2.0mm ± 2.5 using CBCT compared to 4.9mm ± 2.8, 3.5mm ± 2.3 and 5.9mm ± 3.4 using kV/kV. ConclusionsIGRT in combination with either FM or CBRT has an equally high accuracy in the matching process of prostate tissue. FM in combination with kV-image pairs combines the advantages of a low imaging dose to the patient with a high precision setup equivalent to a soft tissue match. A reduction of daily setup errors can be achieved allowing reduction of CTV to PTV margins. RB is an unreliable substitute for prostate tissue localization. IGRT in combination with either FM or CBRT has an equally high accuracy in the matching process of prostate tissue. FM in combination with kV-image pairs combines the advantages of a low imaging dose to the patient with a high precision setup equivalent to a soft tissue match. A reduction of daily setup errors can be achieved allowing reduction of CTV to PTV margins. RB is an unreliable substitute for prostate tissue localization.

Purpose: Evaluation of remission- and breast preservation-rates following neoadjuvant chemotherapy alone (CT) or combined preoperative chemo-radiotherapy (CT-RT). Patients and methods: One-hundred-ninety-four women with 198 biopsy-proven breast tumors entered the protocol. Of the 198 tumors evaluated, 64 underwent neoadjuvant CT followed by surgery and adjuvant radiotherapy (CT group) and 134 were treated by preoperative CT-RT followed by surgery (CT-RT group). Mostly EC- or CMF-regimes were used. In case of positive hormone-receptor-status hormonal treatment was applied after surgery. The whole breast was homogenously irradiated using 2 Gy single fractions up to a total dose of 50 Gy, followed by a boost of 6-11 Gy to the tumor. Median time interval between end of neoadjuvant treatment and surgery was 8 weeks (4-24 weeks) and 16 weeks (3-38 weeks) in the CT- and CT-RT group. Results: A histologically proven complete remission (pCR) could be achieved in 2 out of 64 tumors (3%) in the CT- and in 56 out of 134 tumors (42%) in the CT-RT group. The logistic regression analysis including clinical tumor-(cT), lymph node(cN)- and metastasis-status (cM), grading (G), hormone receptor-status (HRS), number of applied preoperative chemotherapy cycles (n preop CT), preoperative tumor volume (preop V) and treatment group (TG) revealed that the hormone receptor status (p= 0.0223) and TG (p<0.0001) were significant factors for achieving pCR. Breast preservation was possible in 55% (74/134) and 41% (26/64) in the CT-RT- and CT group, respectively. The multivariate analysis showed that cT (p=0.0024) and TG (p=0.018) had statistical relevance for breast preservation. Conclusions: Combination of neoadjuvant chemo- and radiotherapy results in a significantly higher rate of complete remission than neoadjuvant chemotherapy alone. The significance for tumor-free-and overall survival has to be evaluated by further follow-up. Tabled 1CT-groupCT-RT-groupTumors (n)64134Median age (yrs)6254Tumor size (cm)3.35preop CT (n)47pCR (n)256Residual invasive tumor (n)6278Breast preservation (n)2674 Open table in a new tab