Optimal Strategies for Managing Prostate-specific Antigen Recurrence After Primary Radiotherapy in Prostate Cancer: The Finnish Perspective.

Biochemical recurrence after radiotherapy for prostate cancer is a clinical dilemma. Patients at low risk of disease progression can be safely monitored. In Finland, options for those with reasonable life expectancy include salvage high-dose-rate brachytherapy and transurethral ultrasound ablation under magnetic resonance imaging guidance.

Synthetic computed tomography based dose calculation in prostate cancer patients with hip prostheses for magnetic resonance imaging-only radiotherapy.

Background and purpose: Metallic hip prostheses cause substantial artefacts in both computed tomography (CT) and magnetic resonance (MR) images used in radiotherapy treatment planning (RTP) for prostate cancer patients. The aim of this study was to evaluate the dose calculation accuracy of a synthetic CT (sCT) generation workflow and the improvement in implant visibility using metal artefact reduction sequences. Materials and methods: The study included 23 patients with prostate cancer who had hip prostheses, of which 10 patients had bilateral hip implants. An in-house protocol was applied to create sCT images for dose calculation comparison. The study compared prostheses volumes and resulting avoidance sectors against planning target volume (PTV) dose uniformity and organs at risk (OAR) sparing. Results: Median PTV dose difference between sCT and CT-based dose calculation among all patients was 0.1 % (-0.4 to 0.4%) (median(range)). Bladder and rectum differences (V50Gy) were 0.2 % (-0.3 to 1.1%) and 0.1 % (-0.9 to 0.5%). The median 3D local gamma pass rate for partial arc cases using a Dixon MR sequence was Γ20%2mm/2% = 99.9%. For the bilateral full arc cases, using a metal artefact reconstruction sequence, the pass rate was Γ20%2mm/2% = 99.0%. Conclusions: An in-house protocol for generating sCT images for dose calculation provided clinically feasible dose calculation accuracy for prostate cancer patients with hip implants. PTV median dose difference for uni- and bilateral patients with avoidance sectors remained <0.4%. The Outphase images enhanced implant visibility resulting in smaller avoidance sectors, better OAR sparing, and improved PTV uniformity.

Salvage HDR brachytherapy for prostate cancer: a high-volume center experience on 100 consecutive patients.

AIM: This study aims to evaluate the safety and efficacy of salvage HDR brachytherapy in patients who have undergone a thorough diagnostic process. MATERIALS AND METHODS: 100 prostate cancer patients - locally relapsed after previous radiotherapy - were treated with salvage HDR brachytherapy to a total dose of 24 Gy. Before treatment, the patients underwent PET imaging, prostate MRI, and prostate biopsies to confirm local relapse and exclude systemic disease. Concomitant ADT was applied in 69 patients. Toxicity and efficacy data were collected as a patient chart review. Toxicity was graded using Common Terminology Criteria for Adverse Events (CTCAE 5.0). RESULTS: The 3-year bDFS and OS were 74% (confidence interval [CI] 95%: 60-87%) and 93% (CI 95%: 84-100%), respectively. Acute Grade 1-2 genitourinary toxicity was observed in 70 patients, 58 patients with Grade 1 and 12 patients with Grade 2, respectively. Acute Grade 1 gastrointestinal toxicity was observed in 8 patients. CONCLUSIONS: This retrospective study shows that salvage HDR brachytherapy is a well-tolerated and effective treatment for histologically proven, local radio-recurrent disease.

Serum tumour associated trypsin inhibitor, as a biomarker for survival in renal cell carcinoma.

OBJECTIVE: Tumour associated trypsin inhibitor (TATI) is a peptide that is a marker for several tumours. TATI may also behave as an acute phase reactant in severe inflammatory disease. Overexpression of TATI predicts an unfavourable outcome for many cancers. This study aimed to evaluate the prognostic value of pre- and postoperative concentration of TATI in serum (S-TATI) of patients with renal cell carcinoma (RCC). MATERIALS AND METHODS: S-TATI was determined by time resolved immunofluorometric assay in preoperative and postoperative samples that were collected from 132 RCC patients, who underwent partial or complete nephrectomy in Helsinki University Hospital from May 2005 to July 2010. RESULTS: Preoperative S-TATI was significantly associated with tumour stage, lymph-node involvement, metastatic stage, Chronic Kidney Disease Stage (CKD grade), and preoperative C-reactive protein level (p < 0.05). Postoperative S-TATI was significantly associated only with CKD grade (p < 0.001). Multivariate Cox regression analysis of postoperative S-TATI, as a continuous variable, was an independent prognostic factor for overall survival (HR = 1.01, 95% CI = 1.00-1.01, p = 0.03) and cancer-specific survival (CSS) (HR = 1.01, 95% CI = 1.00-1.02, p = 0.004). CONCLUSIONS: Our data suggest that elevated postoperative S-TATI may be associated with adverse prognosis in RCC patients.

PTEN and ERG expression in MRI-ultrasound guided fusion biopsy correlated with radical prostatectomy findings in men with prostate cancer.

BACKGROUND: Conventional systematic prostate biopsies (SBx) have multiple limitations, and magnetic resonance imaging (MRI)-ultrasound fusion targeting is increasingly applied (fusion biopsies [FBx]). In our previous studies, we have shown that loss of the tumor suppressor gene phosphatase and tensin homolog (PTEN) in radical prostatectomy (RP) specimens predicts poor disease-specific survival, and in active surveillance (AS), PTEN loss in SBx predicts an adverse AS outcome, although SBx PTEN status does not correlate well with the corresponding RP status. Here, we have hypothesized that PTEN and erythroblast transformation-specific related gene (ERG) status in FBx correlate better with RP than they would in SBx. METHODS: A total of 106 men, who had undergone FBx and subsequent RP in a single center between June 2015 and May 2017 were included. Fifty-three of the men had concomitant or previous SBx's. All biopsy and RP specimens were collected, and tissue microarrays (TMA) were constructed from RP specimens. Immunohistochemical stainings for PTEN and ERG expression were conducted on biopsies and RP TMAs and results were compared by using Fisher's exact test. RESULTS: The immunohistochemical predictive power of FBx, determined by the concordance of biopsy PTEN and ERG status with RP, is superior to SBx (77.6% vs 66.7% in PTEN, 92.4% vs 66.6% in ERG). FBx was superior to SBx in correlation with RP Gleason Grade Groups and MRI prostate imaging reporting and data system scores. CONCLUSION: FBx grading correlates with RP histology and MRI findings and predicts the biomarker status in the RP specimens more accurately than SBx. A longer follow-up is needed to evaluate if this translates to better prediction of disease outcomes, especially in AS and radiation therapy where prostatectomy specimens are not available for prognostication.

Evolving Clinical Picture of Renal Cell Carcinoma: A Population-Based Study from Helsinki.

BACKGROUND: There is a lack of detailed population-based data for renal cell carcinoma (RCC). OBJECTIVES: The study aimed to examine the contemporary changes in the clinical picture and treatment of RCC. METHODS: A total of 1,719 consecutive patients living in the Helsinki metropolitan area with a solid or cystic renal mass (Bosniak 3-4) ≥10 mm were identified. Data from medical records was evaluated for clinical characteristics and treatments in the periods I (2006-2008), II (2009-2011), III (2012-2014), and IV (2015-2016). RESULTS: The proportions of patients with comorbidities (Charlson index ≥2) and frailty (Eastern Co-operative Oncology Group classification ≥2) increased significantly during the study period. The percentage of clinical stage I patients, cystic tumors and use of needle biopsies increased significantly. Use of observation increased from 9% (I) to 32% (IV; p < 0.001). First-line oncological treatments within 6 months were given to 47% of 262 patients with metastases and -cytoreductive nephrectomy (CN) was delivered to 54% of those patients. CONCLUSIONS: The size of renal tumors continued to decrease, while the percentage of patients with significant comorbidity or frailty increased. Active surveillance emerged as the initial strategy. Tyrosine kinase inhibitors with CN remained the primary option in patients with metastatic RCC.

MRI-only based radiation therapy of prostate cancer: workflow and early clinical experience.

BACKGROUND: Magnetic resonance imaging (MRI) is the most comprehensive imaging modality for radiation therapy (RT) target delineation of most soft tissue tumors including prostate cancer. We have earlier presented step by step the MRI-only based workflow for RT planning and image guidance for localized prostate cancer. In this study we present early clinical experiences of MRI-only based planning. MATERIAL AND METHODS: We have analyzed the technical planning workflow of the first 200 patients having received MRI-only planned radiation therapy for localized prostate cancer in Helsinki University Hospital Cancer center. Early prostate specific antigen (PSA) results were analyzed from n = 125 MRI-only patients (n = 25 RT only, n = 100 hormone treatment + RT) and were compared with the corresponding computed tomography (CT) planned patient group. RESULTS: Technically the MRI-only planning procedure was suitable for 92% of the patients, only 8% of the patients required supplemental CT imaging. Early PSA response in the MRI-only planned group showed similar treatment results compared with the CT planned group and with an equal toxicity level. CONCLUSION: Based on this retrospective study, MRI-only planning procedure is an effective and safe way to perform RT for localized prostate cancer. It is suitable for the majority of the patients.

Practical differences between luteinizing hormone-releasing hormone agonists in prostate cancer: perspectives across the spectrum of care.

BACKGROUND: Androgen deprivation therapy (ADT) with luteinizing hormone-releasing hormone (LHRH) agonists is well established for the treatment of men with metastatic prostate cancer. As clear differences in efficacy, safety, or tolerability between the available LHRH agonists are lacking, the healthcare management team needs to look to practical differences between the formulations when selecting therapy for their patients. Moreover, as the economic burden of prostate cancer rises alongside earlier diagnosis and improved survival, the possibility for cost savings by using products with specific features is growing in importance. METHODS: A review was conducted to summarize the information on the different LHRH agonist formulations currently available and offer insight into their relative benefits and disadvantages from the perspectives of physicians, a pharmacist, and a nurse. RESULTS: The leuprorelin acetate and goserelin acetate solid implants have the advantage of being ready to use with no requirement for refrigeration, whereas powder and microsphere formulations have to be reconstituted and have specific storage or handling constraints. The single-step administration of solid implants, therefore, has potential to reduce labor time and associated costs. Dosing frequency is another key consideration, as administering the injection provides an opportunity for face-to-face interaction between the patient and healthcare professionals to ensure therapy is optimized and give reassurance to patients. Prostate cancer patients are reported to prefer 3- or 6-monthly dosing, which aligns with the monitoring frequency recommended in European Association of Urology guidelines and has been shown to result in reduced annual costs compared with 1-month formulations. CONCLUSIONS: A number of practical differences exist between the different LHRH agonist preparations available, which may impact on clinical practice. It is important for healthcare providers to be aware and carefully consider these differences when selecting treatments for their prostate cancer patients.

Surgery for metastases of renal cell carcinoma: outcome of treatments and preliminary assessment of Leuven-Udine prognostic groups in the targeted therapy era.

AIM: This study was conducted to evaluate the efficacy of surgical treatment for metastases accompanied by modern targeted therapies and to evaluate the performance of the Leuven-Udine (L.U.) prognostic groups model. METHODS: This retrospective analysis included 97 consecutive patients with metastatic renal cell carcinoma (mR.C.C.) who underwent surgery for metastases at Helsinki University Hospital between 2006 and 2017. The endpoints were overall survival (O.S.), cancer-specific survival (C.S.S.), recurrence-free survival (R.F.S.) and interval from diagnosis to oncological treatment. RESULTS: The median follow-up time was 46 months (interquartile range, I.Q.R. = 24-74). The estimated median O.S. was 67 months (I.Q.R. = 30-130). A radical surgical result at metastasectomy was achieved in 46 of 97 patients (47%). Of those 46 patients, 28 (61%) experienced recurrence after complete metastasectomy. Median R.F.S. after complete metastasectomy was 10 months (I.Q.R. = 3-37). Five-year O.S. was 59% for patients with complete metastasectomy and 44% for patients with non-complete metastasectomy (p = .035). The median interval from diagnosis to the initiation of targeted oncological treatment was 19 months for patients with non-complete metastasectomy and has hitherto not been reached for patients with complete metastasectomy (p = .006). A statistically significant validation of the prognostic value of the L.U. prognostic groups for predicting C.S.S. was not obtained (p = .420). CONCLUSIONS: Metastasectomy is an option for selected patients with mR.C.C. Complete resection should be attempted when feasible. The data failed to support the prognostic significance of the L.U. model in patients with mR.C.C.

Switching from an LHRH Antagonist to an LHRH Agonist: A Case Report of 10 Finnish Patients with Advanced Prostate Cancer.

INTRODUCTION: Luteinizing hormone-releasing hormone (LHRH) analogues are widely used for the treatment of advanced hormone-dependent prostate cancer. However, there are currently no clinical guidelines for switching between LHRH analogues. It has been reported that there may be clinical benefits for patients switching between different formulations of LHRH agonists, as well as from an LHRH agonist to LHRH antagonist, but there are no published data on switching from an LHRH antagonist to an LHRH agonist. In this paper, we summarize the clinical notes of 10 patients with hormone-sensitive advanced prostate cancer who switched from an LHRH antagonist to an LHRH agonist. METHODS: Patients with T3N0M0-T4N1M1 prostate cancer experiencing injection site reactions, such as pain and swelling, with monthly degarelix (Firmagon®) subcutaneous injections were switched to the 3-monthly leuprorelin acetate implant (Leuprorelin Sandoz®) subcutaneous injections. RESULTS: Mean patient age was 75 years (SD 8.3; range 59-85) and Gleason scores ranged from 7 to 9. The mean [±standard deviation (SD)] duration of degarelix treatment was 5 ± 3.7 months (range 2-13). After switching, prostate serum antigen levels were comparable or reduced from those measured prior to switching, showing that efficacy was not compromised. Throughout the course of treatment, no patients reported injection site reactions. Patients reported increased satisfaction with the leuprorelin acetate implant versus degarelix, mainly because of a lack of injection site reactions and reduced frequency of injection. CONCLUSION: This is the first report of the clinical experience and potential cost implications of switching from an LHRH antagonist to an LHRH agonist. These data are consistent with other experiences of switching between LHRH analogues in terms of efficacy, safety, and potential cost savings, and provide preliminary evidence that the switch from an LHRH antagonist to an agonist is safe and equally efficacious.

Outcome of surgery for patients with renal cell carcinoma and tumour thrombus in the era of modern targeted therapy.

OBJECTIVE: This study evaluated the clinical outcome of patients with renal cell carcinoma (RCC) with tumour thrombus (TT) after surgical management. MATERIALS AND METHODS: In total, 142 consecutive RCC patients with TT who were operated on in Helsinki University Hospital between 2006 and 2014 were analysed. Eighty-eight (62%) of these patients had been operated on with radical intention and 54 (38%) with cytoreductive intention. A total of 73 patients (51%) received postoperative targeted therapy. The primary endpoint was cancer-specific survival (CSS). RESULTS: The 5 year CSS for level of involvement of TT in the renal vein, subdiaphragmatic vena cava and supradiaphragmatic vena cava was 60% (81 patients), 43% (52 patients) and 51% (nine patients), respectively (p = .42). The median CSS for lymph-node involvement was 63 months for patients with no lymph-node involvement but 10 months for patients with lymph-node involvement (p < .01). The median CSS for metastasis status was 63 months for patients with no metastases compared with 18 months for patients with metastases (p < .01). Among several factors examined, WHO performance status (p = .04), tumour necrosis (p = .05), presence of distant metastases (p = .04) and tumour histology (p = .05) were associated with CSS in the multivariate analysis. CONCLUSIONS: Operative treatment for RCC with TT is associated with good prognosis when there is no lymph-node involvement or distant metastases.

Hand-assisted laparoscopic versus open partial nephrectomy in patients with T1 renal tumor: Comparative perioperative, functional and oncological outcome.

OBJECTIVE: Studies comparing hand-assisted laparoscopic partial nephrectomy (HALPN) and open partial nephrectomy (OPN) for T1 kidney tumors are scarce. This study investigated the perioperative, functional and oncological outcomes of these methods. MATERIALS AND METHODS: A prospective institutional kidney tumor register was used to identify patients between January 2006 and May 2014 undergoing HALPN (n = 139) or OPN (n = 165) for tumors 7 cm or smaller with non-absolute indication for nephron-sparing surgery. The outcomes were compared using univariate and multivariate statistical methods. RESULTS: HALPN and OPN groups were similar with regard to tumor characteristics but HALPN patients were 2 years younger (p = 0.001) and had less comorbidity. Fewer intraoperative complications were encountered in HALPN than in OPN patients (7.2% vs 12.7%, p = 0.043). HALPN patients had less all-grade postoperative 30 day complications than OPN patients (27% vs 41%, p = 0.037), but there was no significant difference in Clavien 3-5 complications. Glomerular filtration rate 3 months after operation was lower in the HALPN than in the OPN group (7.1 ± 12.7% vs 10.0 ± 12.4%, p = 0.054). There was no difference in overall survival or recurrence-free survival during the median follow-up of 35 months. CONCLUSIONS: HALPN is a feasible method to achieve equal perioperative, functional and oncological outcomes compared to OPN in patients with tumors 7 cm or smaller in diameter.

Converting from CT- to MRI-only-based target definition in radiotherapy of localized prostate cancer: A comparison between two modalities.

PURPOSE: To investigate the conversion of prostate cancer radiotherapy (RT) target definition from CT-based planning into an MRI-only-based planning procedure. MATERIALS AND METHODS: Using the CT- and MRI-only-based RT planning protocols, 30 prostate cancer patients were imaged in the RT fixation position. Two physicians delineated the prostate in both CT and T2-weighted MRI images. The CT and MRI images were coregistered based on gold seeds and anatomic borders of the prostate. The uncertainty of the coregistration, as well as differences in target volumes and uncertainty of contour delineation were investigated. Conversion of margins and dose constraints from CT- to MRI-only-based treatment planning was assessed. RESULTS: On average, the uncertainty of image coregistration was 0.4 ± 0.5 mm (one standard deviation, SD), 0.9 ± 0.8 mm and 0.9 ± 0.9 mm in the lateral, anterior-posterior and base-apex direction, respectively. The average ratio of the prostate volume between CT and MRI was 1.20 ± 0.15 (one SD). Compared to the CT-based contours, the MRI-based contours were on average 2-7 mm smaller in the apex, 0-1 mm smaller in the rectal direction and 1-4 mm smaller elsewhere. CONCLUSION: When converting from a CT-based planning procedure to an MRI-based one, the overall planning target volumes (PTV) are prominently reduced only in the apex. The prostate margins and dose constraints can be retained by this conversion.

Renal tumour anatomical characteristics and functional outcome after partial nephrectomy.

OBJECTIVE: Anatomical features of renal tumours may be useful in predicting glomerular filtration rate (GFR) after partial nephrectomy. In this study, anatomical classification systems (ACSs) were compared to predict changes in renal function after surgery. MATERIALS AND METHODS: A group of 294 patients with T1 renal tumours receiving partial nephrectomy between January 2006 and June 2013 were identified from the institutional kidney tumour database. Preoperative images from computed tomography or magnetic resonance imaging were reviewed to assess diameter, PADUA (preoperative aspects and dimensions used for an anatomical) classification score, RENAL (radius, exophytic/endophytic properties of the tumour, nearness of tumour deepest portion to the collecting system or sinus, anterior/posterior descriptor and location relative to polar lines) nephrometry score, centrality index (C index) and renal tumour invasion index (RTII). GFR was estimated using the Modification of Diet in Renal Disease equation preoperatively and 3 months after operation. Linear and logistic regression were applied as statistical methods. RESULTS: Mean tumour diameter was 3.0 ± 2.2 cm (range 1.0-7.0 cm). GFR was 85 ± 22 ml/min/1.73 m² before the operation and 77 ± 21 ml/min/1.73 m² (-8% change) 3 months after the operation. In univariate linear regression, the percentage change in GFR was weakly but statistically significantly associated with surgical approach (p = 0.04), indication for nephron sparing (p = 0.02), preoperative GFR (p < 0.001), PADUA (p = 0.02), RENAL (p = 0.01) and RTII (p = 0.003). In multivariate logistic regression analysis among patients with tumours 3 cm or larger, PADUA (odds ratio 1.55, p = 0.021) and RTII (odds ratio 3.87, p = 0.037) predicted at least a 20% reduction in GFR. CONCLUSIONS: Renal tumour ACSs may be clinically useful in predicting changes in renal function after partial nephrectomy in patients with larger tumours. The performance of RTII is equal to that of other ACSs in predicting changes in GFR.

Gold seed fiducials in analysis of linear and rotational displacement of the prostate bed.

BACKGROUND AND PURPOSE: This study aimed to investigate the magnitude of interfraction prostate bed motion during radiotherapy using both the implanted gold seed fiducials and the soft tissue registration and to define reasonable planning target volume (PTV) margins for different localization methods. MATERIAL AND METHODS: Thirteen prostatectomized prostate cancer patients, after implanting four gold seed fiducials into their prostate bed, were imaged daily using a pretreatment cone-beam computed tomography (CBCT). Linear and the rotational prostate bed motion (PBM) was measured for 466 CBCTs. RESULTS: The linear PBM mean and standard deviation values in millimeters are 0.0 ± 0.5, 0.7 ± 2.1 and 0.8 ± 1.6 in the LR, SI and AP axes, respectively. In 20% of the fractions the rotation of the prostate bed in sagittal plane exceeds ±6° and in 5% it exceeds ±10° from the position on the planning CT. In the transversal and coronal planes 1% and 2% of it exceeds ±6°. The PTV margins are 2.4, 6.5 and 6.6mm in the LR, SI and AP axes, respectively, if imaging is performed for the first three treatment fractions. CONCLUSION: The linear PBM is largest in the SI and AP axis, whereas the rotation is largest in the sagittal plane. Bone localization during the first three treatment fractions can reduce PTV margins by 52%, 18% and 10% in the LR, SI and AP axes, respectively, whereas in daily CBCT the use of the gold seed fiducials seems profitable.

Renal tumour invasion index as a novel anatomical classification predicting urological complications after partial nephrectomy.

OBJECTIVE: The goal of anatomical classification systems (ACSs) is to assess renal tumour complexity and predict surgical complications. However, the present ACSs may include some relatively unimportant components and may be complicated to use. This study introduces the invasion depth of the renal tumour divided by the parenchymal thickness, called the renal tumour invasion index (RTII), as a novel ACS and compares it with previous ACSs in predicting urological complications after partial nephrectomy. MATERIAL AND METHODS: This retrospective single-institution study assessed 280 consecutive patients subjected to a planned partial nephrectomy. The main outcome was perioperative 30-day urological complications. RTII was compared with the PADUA (preoperative aspects and dimensions used for an anatomical) classification score, RENAL (radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior and location relative to polar lines) nephrometry score and C (centrality) index to predict urological complications, using statistical methods of receiver operating curve and logistic binary regression. RESULTS: Areas under the curve for RTII, RENAL, C index and PADUA were 0.64 (95% CI 0.57-0.72, p < 0.001), 0.61 (95% CI 0.54-0.69, p = 0.004), 0.64 (95% CI 0.57-0.71, p < 0.001) and 0.57 (95% CI 0.49-0.65, p = 0.06), respectively, indicating that all the ACSs studied are able to predict urological complications. Similarly, in a multivariate logistic regression model adjusted for comorbidity and surgical approach, all ACSs were statistically significant predictors of urological complications. CONCLUSIONS: RTII is as good as the previous more complicated ACSs in predicting urological complications after partial nephrectomy. As a simple measurement with a straightforward anatomical interpretation, RTII may be useful in counselling patients and stratifying patients in studies.

Papillary renal cell cancer is strongly associated with simple renal cysts.

INTRODUCTION: The purpose of this study was to evaluate the prevalence of simple renal cysts (SRCs) in patients with renal neoplasia. PATIENTS AND METHODS: The study population consisted of 482 patients who underwent partial or radical nephrectomy for kidney tumour between 2006 and 2010. Prevalence of cysts was evaluated retrospectively on a preoperative CT or MRI scan. RESULTS: SRCs are more prevalent in patients with papillary renal cell cancer (RCC) than patients with clear cell RCC. All obese (BMI ≥30) patients in our study population had SRCs. CONCLUSIONS: This is the first study to show an association between SRCs and papillary RCC.

Implementation of adaptive radiation therapy for urinary bladder carcinoma: imaging, planning and image guidance.

BACKGROUND: Adaptive radiation therapy (ART) for urinary bladder cancer has emerged as a promising alternative to conventional RT with potential to minimize radiation-induced toxicity to healthy tissues. In this work we have studied bladder volume variations and their effect on healthy bladder dose sparing and intrafractional margins, in order to refine our ART strategy. MATERIAL AND METHODS: An online ART treatment strategy was followed for five patients with urinary bladder cancer with the tumors demarcated using Lipiodol(®). A library of 3-4 predefined treatment plans for each patient was created based on four successive computed tomography (CT) scans. Cone beam CT (CBCT) images were acquired before each treatment fraction and after the treatment at least weekly. In partial bladder treatment the sparing of the healthy part of the bladder was investigated. The bladder wall displacements due to bladder filling were determined in three orthogonal directions (CC, AP, DEX-SIN) using the treatment planning CT scans. An ellipsoidal model was applied in order to find the theoretical maximum values for the bladder wall displacements. Moreover, the actual bladder filling rate during treatment was evaluated using the CBCT images. Results. In partial bladder treatment the volume of the bladder receiving high absorbed doses was generally smaller with a full than empty bladder. The estimation of the bladder volume and the upper limit for the intrafractional movement of the bladder wall could be represented with an ellipsoidal model with a reasonable accuracy. Observed maximum growth of bladder dimensions was less than 10 mm in all three orthogonal directions during 15 minute interval. CONCLUSION: The use of Lipiodol contrast agent enables partial bladder treatment with reduced irradiation of the healthy bladder volume. The ellipsoidal bladder model can be used for the estimation of the bladder volume changes and the upper limit of the bladder wall movement during the treatment fraction.

Adaptive radiotherapy in muscle invasive urinary bladder cancer--an effective method to reduce the irradiated bowel volume.

BACKGROUND AND PURPOSE: To evaluate the benefits of adaptive radiotherapy for bladder cancer in decreasing irradiation of small bowel. MATERIAL AND METHODS: Five patients with muscle invasive bladder cancer received adaptive radiotherapy to a total dose of 55.8-65 Gy with daily cone-beam computed tomography scanning. The whole bladder was treated to 45-50.4 Gy, followed by a partial bladder boost. The plan of the day was chosen from 3 to 4 pre-planned treatment plans according to the visible extent of bladder wall in cone-beam computed tomography images. Dose volume histograms for intestinal cavity volumes were constructed and compared with corresponding histograms calculated for conventional non-adaptive radiotherapy with single treatment plan of 2 cm CTV-PTV margins. CTV dose coverage in adaptive treatment technique was compared with CTV dose coverage in conventional radiotherapy. RESULTS: The average volume of intestinal cavity receiving ≥ 45 Gy was reduced from 335 ± 106 cm(3) to 180 ± 113 cm(3) (1SD). The maximum volume of intestinal cavity spared at 45 Gy on a single patient was 240 cm(3), while the minimum volume was 65 cm(3). The corresponding reduction in average intestinal cavity volume receiving ≥ 45 Gy calculated for the whole bladder treatment only was 66 ± 36 cm(3). CTV dose coverage was improved on two out of five patients and decreased on three patients. CONCLUSIONS: Adaptive radiotherapy considerably reduces dose to the small bowel, while maintaining the dose coverage of CTV at similar level when compared to the conventional treatment technique.