Pelvic Intensity-modulated Radiotherapy Research Articles

Impact of Pelvic Rotational Setup Error on Lymph Nodal Dose in Whole Pelvic IMRT Using Fiducial Markers.

The aim of this study was to investigate the impact of pelvic rotational setup error on lymph nodal dose in the whole pelvic intensity-modulated radiation therapy using the fiducial marker. The dose differences of clinical target volume for pelvic lymph node (CTVLN) due to isocenter (IC) shift and pelvic rotation were evaluated using the radiation treatment planning system. The rotated computed tomography (CT) images were created for the simulation of the pelvic rotation. The original CT images were rotated around the IC of the original plan in the pitch and roll directions up to±3.0 deg. at 1.0 deg. intervals. As simulated plans, IC positions were shifted in the anterior-posterior and superior-inferior directions up to±10 mm at 2 mm intervals in the original and rotated CT images, and the dose distributions were calculated. The dose calculation was performed for each CT image while keeping the movement of multi leaf collimator and the monitor unit of the original plan. The differences between D98% of CTVLN in the original plan and simulated plans were calculated. In the posterior direction shifts of 4, 6, 8, and 10 mm, the dose reduction of 0.7, 2.1, 6.1, and 11.9% from the original plan were found for D98% of CTVLN, respectively. The dose reductions due to the rotation of pitch direction were greater than the rotation of roll direction. In the posterior direction shifts of 4, 6, 8, and 10 mm with 3.0 deg. rotation of pitch direction, the dose reduction of 2.2, 6.8, 12.8, and 19.0% from the original plan were found, respectively. The dose reduction of CTVLN might be occurred due to the rotational setup error of pitch direction.

Nodal Clearance Rate and Long-Term Efficacy of Individualized Sentinel Node–Based Pelvic Intensity Modulated Radiation Therapy for High-Risk Prostate Cancer

To assess the efficacy of individual sentinel node (SN)-guided pelvic intensity modulated radiation therapy (IMRT) by determining nodal clearance rate [(n expected nodal involvement - n observed regional recurrences)/n expected nodal involvement] in comparison with surgically staged patients. Data on 475 high-risk prostate cancer patients were examined. Sixty-one consecutive patients received pelvic SN-based IMRT (5 × 1.8 Gy/wk to 50.4 Gy [pelvic nodes + individual SN] and an integrated boost with 5 × 2.0 Gy/wk to 70.0 Gy to prostate + [base of] seminal vesicles) and neo-/adjuvant long-term androgen deprivation therapy; 414 patients after SN-pelvic lymph node dissection were used to calculate the expected nodal involvement rate for the radiation therapy sample. Biochemical control and overall survival were estimated for the SN-IMRT patients using the Kaplan-Meier method. The expected frequency of nodal involvement in the radiation therapy group was estimated by imputing frequencies of node-positive patients in the surgical sample to the pattern of Gleason, prostate-specific antigen, and T category in the radiation therapy sample. After a median follow-up of 61 months, 5-year OS after SN-guided IMRT reached 84.4%. Biochemical control according to the Phoenix definition was 73.8%. The nodal clearance rate of SN-IMRT reached 94%. Retrospective follow-up evaluation is the main limitation. Radiation treatment of pelvic nodes individualized by inclusion of SNs is an effective regional treatment modality in high-risk prostate cancer patients. The pattern of relapse indicates that the SN-based target volume concept correctly covers individual pelvic nodes. Thus, this SN-based approach justifies further evaluation, including current dose-escalation strategies to the prostate in a larger prospective series.

Favorable outcomes in locally advanced and node positive prostate cancer patients treated with combined pelvic IMRT and androgen deprivation therapy.

BackgroundThe most appropriate treatment for men with prostate cancer and positive pelvic nodes, N+, is an area of active controversy. We report our 5-years outcomes in men with locally advanced prostate cancer (T1-T4N0-N1M0) treated with definitive radiotherapy encompassing the prostate and pelvic lymph nodes (intensity modulated radiotherapy, IMRT) and long-term androgen deprivation therapy (ADT).Material and methodsOf the 138 consecutive eligible men all living patients have been followed up to almost 5 years. Survival endpoints for 5-year biochemical failure-free survival (BFFS), relapse-free survival (RFS), prostate cancer-specific survival (PCSS), and overall survival (OS) were assessed by Kaplan-Meier analysis. Univariate and multivariate Cox regression proportional hazards models were constructed for all survival endpoints. The RTOG morbidity grading system for physician rated toxicity was applied.ResultsPatients with locally advanced T3-T4 tumors (35 %) and N1 (51 %) have favorable outcome when long-term ADT is combined with definitive radiotherapy encompassing pelvic lymph nodes. The 5-year BFFS, RFS, PCSS and OS were 71.4, 76.2, 94.5 and 89.0 %, respectively. High Gleason sum (9–10) had a strong independent prognostic impact on BFFS, RFS and OS (p = 0.001, <0.001, and 0.005 respectively). The duration of ADT (= > 28 months) showed a significant independent association with improved PCSS (p = 0.02) and OS (p = 0.001). Lymph node involvement was not associated with survival endpoints in the multivariate analysis. The radiotherapy induced toxicity seen in our study population was moderate with rare Grade 3 GI side effects and up to 11 % for Grade 3 GU consisting mainly of urgency and frequency.ConclusionPelvic IMRT in combination with long-term ADT can achieve long-lasting disease control in men with N+ disease and unfavorable prognostic factors.Electronic supplementary materialThe online version of this article (doi:10.1186/s13014-015-0540-3) contains supplementary material, which is available to authorized users.

Long-term Outcomes Using Adjuvant Pelvic Intensity Modulated Radiation Therapy for Endometrial Carcinoma

Long-term Outcomes Using Adjuvant Pelvic Intensity Modulated Radiation Therapy for Endometrial Carcinoma

Dose-Volume Effects on Gastrointestinal Complications in Patients Receiving Postoperative Pelvic Intensity Modulated Radiation Therapy for Cervical Cancer Using a Principal Component Analysis

Dose-Volume Effects on Gastrointestinal Complications in Patients Receiving Postoperative Pelvic Intensity Modulated Radiation Therapy for Cervical Cancer Using a Principal Component Analysis

Modeling early haematologic adverse events in conformal and intensity-modulated pelvic radiotherapy in anal cancer

Background and purposeTo determine if there are differences between dose to pelvic bone marrow (PBM) using intensity modulated radiotherapy (IMRT) under UK guidance versus conformal radiotherapy (CRT) per ACT II protocol and if differences translate to rates of early haematological adverse events grade 3 or greater (HT3+). Methods and materialsTwo groups of 20+ patients, treated under IMRT and CRT regimes respectively, were identified. All patients underwent weekly blood cell count: haemoglobin (HgB), white cell count (WCC), absolute neutrophil count (ANC) and platelets (plats).Percent volume of PBM and sub structures receiving 5–25Gy were tested for statistical significance. Regression models were used to test for correlation to blood counts. NTCP modeling was also performed. ResultsPMB dose metrics showed a significant increase in the IMRT group. Regression analysis showed iliac and lumbosacral PBM dose metrics to associate with reduced nadir ANC and WCC. NTCP at HT3+ was 0.13 using IMRT relative to 0.07 using CRT (p<0.05). ConclusionWhilst this is a relatively small retrospective study and lacks information on the distribution of active PBM, IMRT treatment has been shown to significantly increase PMB irradiation. PBM dose metrics have been shown to be predictive of WCC and ANC suppression. NTCP modeling predicts much high risk of HT3+. Paradoxically, actual rates of HT3+ were comparable suggesting that differences in the distributions of dose metrics maybe a significant factor and/or that there are insufficiency in the NTCP modeling.

Can dosimetric parameters predict acute hematologic toxicity in rectal cancer patients treated with intensity-modulated pelvic radiotherapy?

BackgroundTo identify dosimetric parameters associated with acute hematologic toxicity (HT) in rectal cancer patients undergoing concurrent chemotherapy and intensity-modulated pelvic radiotherapy.MethodsNinety-three rectal cancer patients receiving concurrent capecitabine and pelvic intensity-modulated radiation therapy (IMRT) were analyzed. Pelvic bone marrow (PBM) was contoured for each patient and divided into three subsites: lumbosacral spine (LSS), ilium, and lower pelvis (LP). The volume of each site receiving 5–40 Gy (V 5, V10, V15, V20, V30, and V40, respectively) as well as patient baseline clinical characteristics was calculated. The endpoint for hematologic toxicity was grade ≥ 2 (HT2+) leukopenia, neutropenia, anemia or thrombocytopenia. Logistic regression was used to analyze correlation between dosimetric parameters and grade ≥ 2 hematologic toxicity.ResultsTwenty-four in ninety-three patients experienced grade ≥ 2 hematologic toxicity. Only the dosimetric parameter V40 of lumbosacral spine was correlated with grade ≥ 2 hematologic toxicity. Increased pelvic lumbosacral spine V40 (LSS-V40) was associated with an increased grade ≥ 2 hematologic toxicity (p = 0.041). Patients with LSS-V40 ≥ 60 % had higher rates of grade ≥ 2 hematologic toxicity than did patients with lumbosacral spine V40 < 60 % (38.3 %, 18/47 vs.13 %, 6/46, p =0.005). On univariate and multivariate logistic regression analysis, lumbosacral spine V40 and gender was also the variable associated with grade ≥ 2 hematologic toxicity. Female patients were observed more likely to have grade ≥ 2 hematologic toxicity than male ones (46.9 %, 15/32 vs 14.8 %, 9/61, p =0.001).ConclusionsLumbosacral spine -V40 was associated with clinically significant grade ≥ 2 hematologic toxicity. Keeping the lumbosacral spine -V40 < 60 % was associated with a 13 % risk of grade ≥ 2 hematologic toxicity in rectal cancer patients undergoing concurrent chemoradiotherapy.

90例子宫颈癌调强放疗联合三维近距离治疗的疗效分析

目的：探讨调强放射治疗(intensity odulated radiation therapy, IMRT)联合三维近距离治疗(3D Brachytherapy Treatment, 3D-BT)宫颈癌的临床疗效及毒副反应。方法：回顾性分析90例Ⅱb期~Ⅲb期非手术宫颈癌患者采取全盆腔IMRT + 三维近距离治疗 + 同步化疗的1、2、3年生存率及局部控制率。外照射总量：50.4~56.35 Gy；三维近距离治疗5次(6.25 GyEGD2)。随访采用门诊复查联合电话随访。结果：90例患者1、2、3年生存率，分别为92.22%、84.44%、80%。局部控制率为93.3%。消化系统早期未出现III级以上毒副反应，晚期出现III级分、毒副反应2例。泌尿系统早期未出现III级以上毒副反例，晚期III级毒副反应1例。结论：中晚期宫颈癌IMRT联合三维近距离治疗及同步化疗具有较好耐受性，1、2、3年生存率分别达92.22%、84.44%、80%，IMRT可作为宫颈癌治疗进一步发展方向。 Objective: To discuss the clinical effects and side effects of intensity modulated radiation therapy combining 3D Brachytherapy Treatment on treating cervical cancer. Method: A retrospective analysis was made on 1-, 2-, 3-year survival rate and local control rate of 90 cases of II b period - III b period non-surgical cervical cancer patients who adopted whole pelvic IMRT+3D-BT+ concur- rent chemotherapy. Total external irradiation amount: 50.4 - 56.35 Gy; 3D Brachytherapy Treat- ment 5 times (6.25 GyEGD2). The follow-up visits adopted outpatient review and telephone follow- up. Result: Among 90 cases, 1-year survival rate is 92.22%, 2-year is 84.44%, 3-year is 80%. And the local control rate is 93.3%. There is no side effects over III levels in the digestive system at the early stage. Two cases suffered from III level side effects at the later stage. There is no side effects over III levels in the urinary system at the early stage. One case suffered from III level side effects at the later stage. Conclusion: Middle and later stage cervical cancer IMRT combining 3D-BT and concurrent chemotherapy have good tolerance. The survival rates of 1-, 2-, 3-year are separately 92.22%, 84.4% and 80%. IMRT can be the further developing direction of cervical cancer treat-ment.

56例宫颈癌术后调强放射治疗(IMRT)的疗效观察

目的：回顾性分析宫颈癌术后IMRT治疗患者1、2、3年盆腔局部控制率、生存率及远期毒副反应。方法：回顾性分析2007年7月~2011年7月间贵州省肿瘤医院子宫颈癌根治术后具有术后放疗指征的患者56例，年龄在26~65岁之间(中位年龄42岁)，其中≥50岁患者22例， Objective: To retrospectively analyze IMRT treatment on partial pelvic control rate, survival rate and future toxic and adverse effects at year 1, 2 and 3 in patients with postoperative cervical cancer. Methods: Fifty-six postoperative cervical cancer patients, aged between 26 - 65 years old (median age of 42 years old) with postoperative radiotherapy indications have carried out the retrospective analysis from July 2007 to July 2011 in Guizhou Cancer Hospital of which 22 patients ≥ 50 years old and 34 patients < 50 years old. Twenty-five patients were in FIGO stage I and 31 patients of stage II. Postoperative pathology showed that 47 patients had squamous cell carcinoma and 9 patients of adenocarcinoma. Factors for postoperative supplement radiotherapy due to highly recurrent risks include positive pelvic lymph nodes (21 cases), lateral uterine invasion (4 cases), invasive depth of neoplasm in excess of 1/2 (20 cases), vessel invasion (11 cases), 56 patients in radiotherapy with full pelvic IMRT, and external exposure of DT50.4 Gy/28 f/5 W. Patient was received Ir192 close range radiotherapy after one month of postoperation, 5 Gy/week, DT20 Gy, as well as paclitaxel (135 - 175 mg/m2) + cisplatin (60 - 80 mg/m2) simultaneous and/or synchronous chemotherapy 2 - 4 cycles. Follow-up was lasting for 3 - 36 months and the total follow-up rate was 95%. Results: One-year overall survival rate and partial pelvic control rate were 100.0% and 96.4%; two-year overall survival rate and partial pelvic control rate were 98.2% and 96.4%; three-year overall survival rate and partial pelvic control rate were 94.6% and 89.2%. Positive lymph nodes and lateral uterine invasion were independent prognostic factors that impacted the overall survival rate while staging, vessel invasion were independent prognostic factors of partial pelvic control rate. According to (RTOG) evaluation criteria of acute and chronic radiation reactions, grade I further rectal reaction was 26.8% and 8.9% for grade II and 1.7% for grade III; grade I further urinary reaction was 23.2% and 5.3% for grade II and 0% for grade III; and grade I further hematological toxicity was 41.1% and 30.3% for grade II and 8.9% for grade III. Conclusion: A satisfactory effect can be achieved on partial pelvic control rate and overall survival rate in IMRT treatment for patients with postoperative cervical cancer, which is in accordance with results reported in several published documents. Moreover, the radiotherapy-related further toxic and adverse effects can be acceptable.

Feasibility Study of Pelvic Helical IMRT for Elderly Patients with Endometrial Cancer

PurposeStandard treatment for early-stage endometrial cancer involves surgery (when possible) followed by brachytherapy or external-beam radiotherapy (EBRT) for high-risk tumors. EBRT is not without toxicity, meaning that it could be difficult to complete for elderly patients, who typically have decreased reserve and resistance to stressors.Patients and methodsPatients aged 70 and over treated between April 2009 and May 2013 for endometrial cancer and received IMRT (Intensity-Modulated Radiation Therapy) were included in this observational study. IMRT could be performed as adjuvant treatment or as an exclusive treatment for patients not amenable to surgery. The primary endpoints of this study were to assess the feasibility and toxicity of pelvic IMRT in this population. Secondary endpoints were to assess disease-specific survival, overall survival, and local control. Predictors of toxicity were also explored.ResultsForty seven consecutive patients were included in the analysis. Median age at diagnosis was 75 years (range, 70–89 years). Eleven patients were aged 80 years and older. Toxicities were found in thirty four patients (72%) during treatment. Among these, toxicity did not exceed grade 2 for 32 patients (68%). Two patients had a grade 3 toxicity (4%). Overall survival rates were 87% and 83% at 1 and 2 years, respectively. Six patients (12.8%) had a local relapse and nine others (19.1%) had distant relapse.ConclusionsPelvic helical IMRT for patients aged 70 and older is feasible with full standard radiation doses, showing that age greater than 70 should not be considered as a reason not to perform optimal treatment.

Consensus Guidelines for Delineation of Clinical Target Volume for Intensity-Modulated Pelvic Radiation Therapy in Postoperative Treatment of Endometrial and Cervical Cancer- An Update

Consensus Guidelines for Delineation of Clinical Target Volume for Intensity-Modulated Pelvic Radiation Therapy in Postoperative Treatment of Endometrial and Cervical Cancer- An Update

Efficacy of pelvic intensity-modulated radiotherapy with hypofractionated simultaneous integrated boost to the prostate for intermediate- and high-risk prostate cancer

Objectives The objective of this study is to evaluate the efficacy as well as acute and late toxicities of pelvic intensity-modulated radiotherapy (IMRT) with hypofractionated simultaneous integrated boost (SIB) to the prostate for patients with intermediate- and high-risk prostate cancer.

Intensity-modulated pelvic radiation therapy and simultaneous integrated boost to the prostate area in patients with high-risk prostate cancer: a preliminary report of disease control.

The aim of the study was to report the clinical results in patients with high-risk prostate cancer treated with pelvic intensity-modulated radiation therapy (IMRT) and simultaneous integrated boost (SIB) to the prostate area. A total of 110 patients entered our study, 37 patients presented with localized prostate cancer and radiological evidence of node metastases or ≥15% estimated risk of lymph node (LN) involvement, while 73 patients underwent postoperative adjuvant or salvage irradiation for biochemical or residual/recurrent disease, LN metastases, or high risk of harboring nodal metastases. All patients received androgen deprivation therapy (ADT) for 2 years. The median follow-up was 56.5 months. For the whole patient group, the 3- and 5-year freedom from biochemical failure were 82.6% and 74.6%, respectively, with a better outcome in patients treated with radical approach. The 3- and 5-year freedom from local failure were 94.4% and 90.2%, respectively, while the 3- and 5-year distant metastasis-free survival were 87.8% and 81.7%, respectively. For all study patients, the rate of freedom from G2 acute rectal, intestinal, and urinary toxicities was 60%, 77%, and 61%, respectively. There was no G3 acute toxicity, ≥G2 late intestinal toxicity, or G3 late urinary or rectal toxicity. The 3- and 5-year ≥G2 freedom from late rectal toxicity rate were 98% and 95%, respectively, while the 3- and 5-year ≥G2 freedom from late urinary toxicity rate were 95% and 88%, respectively. The study concludes that pelvic IMRT and SIB to the prostatic area in association with 2-year ADT was a well-tolerated technique, providing high disease control in patients with prostate cancer requiring LN treatment.

The Effect of Dose Grid Resolution on Dose Volume Histograms for Slender Organs at Risk during Pelvic Intensity-modulated Radiotherapy

PurposeThere are enduring uncertainties regarding the optimal dose grid resolution for use with pelvic intensity-modulated radiotherapy (IMRT) plans in which the adjacent organs at risk are slender and transect the field edge. Therefore, this study evaluated the effect of dose grid resolution on bladder wall dose-volume histogram (DVH) calculations for prostate IMRT plans. Materials and MethodsThe planning computed tomography scans and clinical plans from 15 prostate cancer patients were included in this analysis. For each study computed tomography, the entire inner and outer bladder surfaces were delineated. Nine versions of the clinical plan were created, varying interval between the dose grid calculation points uniformly in three dimensions, whereas all other plan parameters were kept constant. The dose grid increments tested were 1–10 mm. The plans were recalculated and the bladder wall DVH compared against the study benchmark (1 mm grid). ResultsAll the dose grid increments evaluated resulted in a systematic overestimation of the bladder wall volume receiving low doses and an underestimation of the volume receiving high doses. Grid increments <2.5 mm all resulted in mean volume differences less than 1 cm3 across the whole DVH. Grid increments >5.0 mm resulted in mean volume differences greater than 2 cm3. Individual patient analysis revealed that only the 1.5 mm increment resulted in maximum volume differences ≤1 cm3 for every patient across the full length of the DVH curve. Bladder wall thickness ranged from 1.7 to 4.4 mm and displayed no correlation with the magnitude of the dose grid effect. ConclusionsFor an accurate DVH calculation for bladder wall during IMRT planning for prostate cancer, a 1.5 mm dose grid increment is recommended. This finding was unaffected by a normal range in bladder wall thickness. It is suggested that the application of any new treatment planning technique or organ delineation method be accompanied with an evaluation of optimal dose grid resolution.

Low-Dose, Prophylactic, Extended-Field, Intensity-Modulated Radiotherapy Plus Concurrent Weekly Cisplatin for Patients With Stage IB2-IIIB Cervical Cancer, Positive Pelvic Lymph Nodes, and Negative Para-aortic Lymph Nodes

The objective of this study was to assess prospectively the clinical outcomes of low-dose prophylactic extended-field, intensity-modulated radiotherapy (IMRT) plus concurrent weekly cisplatin for patients with stage IB2-IIIB cervical cancer, positive pelvic lymph nodes (PLNs), and negative para-aortic lymph nodes (PALNs). Thirty-two patients with stage IB2-IIIB cervical cancer with positive PLN and negative PALN were included prospectively. All lymph nodes were assessed with positron emission tomography. The PALN field, including lymphatics from the superior border of L1 to the L4-L5 interphase, was irradiated concurrently with pelvic IMRT with a prescribed dose of 40 Gy in 25 fractions. Chemotherapy consisted of cisplatin delivered weekly at a dose of 40 mg/m. Using historical controls treated with pelvic radiotherapy, the survival curves were compared to assess the difference between the 2 treatment periods. Thirty-one patients completed the allocated extended-field IMRT, and all finished the planned pelvic IMRT and brachytherapy. Acute ≥ grade 3 gastrointestinal, genitourinary, and hematologic toxicities were seen in 2, 1, and 18 patients, respectively. During a median follow-up of 33 months, 5 patients developed out-field distant recurrences. One patient had a late grade 3 gastrointestinal complication, and 1 patient had genitourinary toxicity. The 3-year actuarial overall survival, disease-free survival, and distant metastasis-free survival for the study cohort and historic controls were 87% versus 62% (P = 0.02), 82% versus 54% (P = 0.02), and 79% versus 57% (P = 0.01), respectively. Extended-field IMRT of 40 Gy to the PALN plus concurrent cisplatin can effectively eradicate subclinical disease at the PALN and improve the outcome for patients with PLN-positive stage IB2-IIIB cervical cancer.

Adding intensity-modulated radiotherapy to the pelvis does not worsen the adverse effect profiles compared to limited field radiotherapy in men with prostate cancer at 12-month follow-up

To compare adverse effects and toxicity in men with high-risk or locally advanced prostate cancer when adding intensity-modulated radiotherapy (IMRT) technique to the pelvis.Patients and methods. In this prospective follow-up study 180 patients treated with conformal radiotherapy (RAD) to the prostate and vesiculae seminales (boost volumes; PV) and long-term androgen deprivation therapy (LADT), were compared to 90 patients managed by LADT, RAD to the PV and additionally pelvic IMRT. Adverse effects were self-reported at baseline, at 3- and 12-month follow-up. At each time point, the patients rated a questionnaire covering urinary, bowel, and sexual function and bother, quality of life, fatigue, and mental distress.Results. At 3-month follow-up urinary and bowel functions were significantly decreased among IMRT compared to RAD. At 12-month follow-up both groups showed the same reductions within the urinary, bowel and sexual domains. RAD patients had more mental distress than IMRT patients. The scores on quality of life, fatigue and mental distress hardly influenced function or bother within the urinary, bowel or sexual domains.Conclusions. Men treated for high-risk or locally advanced prostate cancer with a combination of LADT, RAD and IMRT including PV and pelvic structures had considerably more acute side effects at 3 months than men treated with LADT and RAD to the PV only. However, at 12-month follow-up, the observed genitourinary and gastrointestinal function and bother were similar in both groups.

Clinical results of an EPID-based in-vivo dosimetry method for pelvic cancers treated by intensity-modulated radiation therapy

The purpose of our work was to investigate the feasibility of using an EPID-based in-vivo dosimetry method initially designed for conformal fields on pelvic dynamic IMRT fields. The method enables a point dose delivered to the patient to be calculated from the transit signal acquired with an electronic portal imaging device (EPID). After defining a set of correction factors allowing EPID pixel values to be converted into absolute doses, several tests on homogeneous water-equivalent phantoms were performed to estimate the validity of the method in reference conditions. The effects of different treatment parameters, such as delivered dose, field size dependence and patient thickness were also studied. The model was first evaluated on a group of 53 patients treated by 3D conformal radiotherapy (3DCRT) and then on 92 patients treated by IMRT, both for pelvic cancers. For each measurement, the dose was reconstructed at the isocenter (DREC) and compared with the dose calculated by our treatment planning system (DTPS). Excellent agreement was found between DREC and DTPS for both techniques. For 3DCRT treatments, the mean deviation between DREC and DTPS for the 211 in-vivo dose verifications was equal to −1.0 ± 2.2% (1SD). Concerning IMRT treatments, the averaged deviation for the 418 fields verified was equal to −0.3 ± 2.6% (1SD) proving that the method is able to reconstruct a dose for dynamic IMRT pelvic fields. Based on these results, tolerance criteria and action levels were established before its implementation in clinical routine.

PO-0736: Pattern of failure after sentinel node based individualization of pelvic IMRT for high risk prostate cancer

PO-0736: Pattern of failure after sentinel node based individualization of pelvic IMRT for high risk prostate cancer

Locally advanced cervical cancer in renal transplant patients: A dilemma between control and toxicity

Treatment of locally advanced cervical cancer in patients with a renal graft requires precautions. The graft is usually in a pelvic position, close to the clinical target volume (CTV). Preserving the graft while ensuring local control is a challenge we have faced in two occasions. We report our experience. We report the cases of 2 patients treated at our institution with a modified workup and therapeutic approach compared with our standard approach. The clinical and technical aspects of both treatments were systematically reviewed and contrasted with reports previously cited in the literature. The first patient received external beam conformal radiotherapy (total dose: 30 Gy in the pelvis) followed by two sessions of MRI-guided brachytherapy (2 × 15 Gy to 90% of the intermediate risk CTV). The second one received pelvic intensity-modulated radiation therapy (total dose: 45 Gy) followed by MRI-guided brachytherapy delivering 15 Gy to 90% of the intermediate risk CTV. Both patients had a complete response and were still in remission more than 2 years after treatment while retaining their graft. No severe late toxicity was reported. External beam radiotherapy followed by brachytherapy is feasible in locally advanced cervical cancer, despite the presence of a kidney graft near the targets. Image-guided adaptive brachytherapy allowed an accurate evaluation of the dose distribution, reaching the recommended treatment thresholds with optimal protection of the graft.

O6 Sentinel node based individualization of pelvic IMRT for high risk prostate cancer

O6 Sentinel node based individualization of pelvic IMRT for high risk prostate cancer