Calculation of complication probability of pion treatment at paul scherrer institute using dose-volume histograms (original) (raw)
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International Journal of Radiation Oncology Biology Physics, 1998
Purpose: To investigate whether Dose-Volume Histogram (DVH) parameters can be used to identify risk groups for developing late gastrointestinal (GI) and genitourinary (GU) complications after conformal radiotherapy for prostate cancer. Methods and Materials: DVH parameters were analyzed for 130 patients with localized prostate cancer, treated with conformal radiotherapy in a dose-escalating protocol (70-78 Gy, 2 Gy per fraction). The incidence of late (>6 months) GI and GU complications was classified using the RTOG/EORTC and the SOMA/LENT scoring system. In addition, GI complications were divided in nonsevere and severe (requiring one or more laser treatments or blood transfusions) rectal bleeding. The median follow-up time was 24 months. We investigated whether rectal and bladder wall volumes, irradiated to various dose levels, correlated with the observed actuarial incidences of GI and GU complications, using volume as a continuous variable. Subsequently, for each dose level in the DVH, the rectal wall volumes were dichotomized using different volumes as cutoff levels. The impact of the total radiation dose, and the maximum radiation dose in the rectal and bladder wall was analyzed as well. Results: The actuarial incidence at 2 years for GI complications >Grade II was 14% (RTOG/EORTC) or 20% (SOMA/LENT); for GU complications >Grade III 8% (RTOG/EORTC) or 21% (SOMA/LENT). Neither for GI complications >Grade II (RTOG/EORTC or SOMA/LENT), nor for GU complications >Grade III (RTOG/ EORTC or SOMA/LENT), was a significant correlation found between any of the DVH parameters and the actuarial incidence of complications. For severe rectal bleeding (actuarial incidence at 2 years 3%), four consecutive volume cutoff levels were found, which significantly discriminated between high and low risk. A trend was observed that a total radiation dose > 74 Gy (or a maximum radiation dose in the rectal wall >75 Gy) resulted in a higher incidence of severe rectal bleeding (p ؍ 0.07). Conclusions: These data show that dose escalation up to 78 Gy, using a conformal technique, is feasible. However, these data have also demonstrated that the incidence of severe late rectal bleeding is increased above certain dose-volume thresholds.
RADIATION DOSE–VOLUME EFFECTS IN RADIATION-INDUCED RECTAL INJURY
The available dose/volume/outcome data for rectal injury were reviewed. The volume of rectum receiving 60GyisconsistentlyassociatedwiththeriskofGrade60Gy is consistently associated with the risk of Grade 60GyisconsistentlyassociatedwiththeriskofGrade2 rectal toxicity or rectal bleeding. Parameters for the Lyman-Kutcher-Burman normal tissue complication probability model from four clinical series are remarkably consistent, suggesting that high doses are predominant in determining the risk of toxicity. The best overall estimates (95% confidence interval) of the Lyman-Kutcher-Burman model parameters are n = 0.09 (0.04-0.14); m = 0.13 (0.10-0.17); and TD 50 = 76.9 (73.7-80.1) Gy. Most of the models of late radiation toxicity come from three-dimensional conformal radiotherapy dose-escalation studies of early-stage prostate cancer. It is possible that intensitymodulated radiotherapy or proton beam dose distributions require modification of these models because of the inherent differences in low and intermediate dose distributions. Ó 2010 Elsevier Inc.
Dosimetric analysis of radiation therapy oncology group 0321: The importance of urethral dose
Practical Radiation Oncology, 2014
Purpose: Radiation Therapy Oncology Group 0321 is the first multi-institutional cooperative group high-dose-rate (HDR) prostate brachytherapy trial with complete digital brachytherapy dosimetry data. This is a descriptive report of the data and an analysis of toxicity. Methods and Materials: Patients are treated with external beam radiation therapy at 45 Gy and 1 HDR implant with 19 Gy in 2 fractions. Implants are done with transrectal ultrasound guidance, and computed tomography (CT)-compatible nonmetallic catheters. HDR planning is done on ≤ 3mm-thick CT slices. The "mean DVH" (dose-volume histogram) of the planning target volume (PTV), implanted volume (IP), and organs at risk are calculated. This includes the mean and standard deviation (SD) of the volume at 10-percentage-point intervals from 10% to 200% of the prescribed dose. The conformal index (COIN), homogeneity index (HI), catheters per implant, and patients per institution are calculated. Multivariate analysis and hazard ratios calculation of all the variables against reported grade ≥ 2 (G2 +) genitourinary (GU) adverse events (Common Terminology Criteria for Adverse Events, version 3) are performed. Results: Dosimetry data are based on 122 eligible patients from 14 institutions. The mean of PTV, IP, catheters per implant, and patients per institution are 54 cc, 63 cc, 19 and 9, respectively. The mean of %V100 PTV , V80 Bladder , V80 Rectum , and V120 Urethra were 94%, 0.40 cc, 0.15 cc, and 0.25 cc, respectively. There are too few G2 + gastrointestinal adverse event (GI AE) for correlative analysis; thus, the analysis has been performed on the more common G2 + GU AE. There are positive correlations noted between both acute and late G2 + GU AE and urethral dose at multiple levels. Positive correlations with late AE are seen with PTV and IP at high-dose levels. A negative Note-Earn CME credit by taking a brief online assessment at https://www.astro.org/JournalCME. Practical Radiation Oncology (2014) 4, 27-34 correlation is seen between HI and acute AE. A higher patient accrual rate is associated with a lower rate of G2 + acute and late AE. Conclusions: Higher urethral dose, larger high-dose volumes, and lower dose homogeneity are associated with greater toxicities. A mean dose-volume histogram comparison at all dose levels should be used for quality control and future research comparison.
Dose–volume effects for normal tissues in external radiotherapy: Pelvis
Radiotherapy and Oncology, 2009
A great deal of quantitative information regarding the dose–volume relationships of pelvic organs at risk has been collected and analysed over the last 10 years. The need to improve our knowledge in the modelling of late and acute toxicity has become increasingly important, due to the rapidly increasing use of inverse-planned intensity-modulated radiotherapy (IMRT) and the consequent need of a quantitative assessment of dose–volume or biological-based cost functions. This comprehensive review concerns most organs at risk involved in planning optimisation for prostate and other types of pelvic cancer. The rectum is the most investigated organ: the largest studies on dose–volume modelling of rectal toxicity show quite consistent results, suggesting that sufficiently reliable dose–volume/EUD-based constraints can be safely applied in most clinical situations. Quantitative data on bladder, bowel, sexual organs and pelvic bone marrow are more lacking but are rapidly emerging; however, for these organs, further investigation on large groups of patients is necessary.
International Journal of Radiation Oncology*Biology*Physics, 2004
1. Martinez AA, Gustavson G, Gonzalez J, et al. Dose escalation using conformal high dose-rate brachytheraopy improves outcome in unfavorable prostate cancer. Int J Radiat Oncol Biol Phys 2002;53:316-327. 2. Valicenti RK, Kirov AS, Meigooni AS, Mishra V, Das RK, Williamson JF. Experimental validation of Monte Carlo dose calculations about a high-intensity Ir-192 source of pulsed dose-rate brachytherapy. Med Phys 1995;22:821-829. 3. Anctil J-C, Clark BG, Arsenault CJ. Experimental determination of dosimetry functions of Ir-192 sources. Med Phys 1998;25:2279-2287. 4. Yu C, Luxton G. TLD dose measurement: A simplified accurate technique for the dose range from 0.5cGy to 1000cGy. Med Phys 1999;26:1010-1016. 5. Karaiskos P, Angelopoulos A, Sakelliou L, et al. Monte Carlo and TLD dosimetry of an 192 Ir high dose rate brachytherapy source. Med Phys 1998;25:1975-1984. 6. Kirov AS, Williamson JF, Meigooni AS, Zhu Y. TLD diode and Monte Carlo dosimetry of an 192 Ir source for high dose rate brachytherapy. Phys Med Biol 1995;40:2015-2036. 7. Brezovich IA, Duan J, Pareek PM, Fiveash J, Ezekiel M. In vivo urethral dose measurements: A method to verify high dose rate prostate treatments. IN REGARD TO FIORINO ET AL.: RECTAL DOSE-VOLUME CONSTRAINTS IN HIGH-DOSE RADIOTHERAPY OF LOCALIZED PROSTATE CANCER (INT J RADIAT ONCOL BIOL PHYS 2003;57:953-962)
Optimization and Comparison of Normal Tissue Complication Probability Models in Radiotherapy
In the context of cancer radiotherapy, toxicity prediction is of the major importance to evaluate and compare dose plans. Normal tissue complication probability (NTCP) models are the major methods to predict and prevent the presentation of toxicities, but they have to be optimized and their predictive capacities have to be evaluated. In this investigation, the six main NTCP models were studied and their parameters were fitted on prostate cancer. The results argue that rectum toxicity within 2 years shows some characteristics of a serial organ (n=0.35). Poisson EUD and Logit EUD models have the better predictive abilities and their use in clinical routine should be studied in further works.
Conformal radiotherapy of the pelvis: assessment of acute toxicity
Radiotherapy and Oncology, 1993
During the last 3 years the Royal Marsden Hospital (RMH) has conducted a prospective randomised trial of conformal pelvic radiotherapy in which dose/volume data and acute toxicity scores have been determined prospectively. Pending completion of the trial, a preliminary analysis has been undertaken of the volume reductions achieved, and of some of the symptom scores. The average symptom score increased during radiotherapy, more markedly for bowel than bladder symptoms. In comparing total doses of 30-38 Gy with 56-65 Gy, watery bowel motions were more frequent with the higher doses (p = 0.013) but in the high-dose group neither this symptom nor tenesmus correlated with volume of rectum treated to at least 90% of the prescribed dose. We conclude that the assessment of the impact of volume on the level of acute symptoms in pelvic radiotherapy is complex, and requires analysis of a range of symptoms, dose levels and normal-tissue volumes. The degree of symptom reduction from conformal radiotherapy will emerge from the RMH randomised trial within the next 12 months.
Medical Physics, 2010
Purpose: Normal tissue complication probability ͑NTCP͒ of the rectum, bladder, urethra, and femoral heads following several techniques for radiation treatment of prostate cancer were evaluated applying the relative seriality and Lyman models. Methods: Model parameters from literature were used in this evaluation. The treatment techniques included external ͑standard fractionated, hypofractionated, and dose-escalated͒ three-dimensional conformal radiotherapy ͑3D-CRT͒, low-dose-rate ͑LDR͒ brachytherapy ͑I-125 seeds͒, and highdose-rate ͑HDR͒ brachytherapy ͑Ir-192 source͒. Dose-volume histograms ͑DVHs͒ of the rectum, bladder, and urethra retrieved from corresponding treatment planning systems were converted to biological effective dose-based and equivalent dose-based DVHs, respectively, in order to account for differences in radiation treatment modality and fractionation schedule. Results: Results indicated that with hypofractionated 3D-CRT ͑20 fractions of 2.75 Gy/fraction delivered five times/week to total dose of 55 Gy͒, NTCP of the rectum, bladder, and urethra were less than those for standard fractionated 3D-CRT using a four-field technique ͑32 fractions of 2 Gy/fraction delivered five times/week to total dose of 64 Gy͒ and dose-escalated 3D-CRT. Rectal and bladder NTCPs ͑5.2% and 6.6%, respectively͒ following the dose-escalated four-field 3D-CRT ͑2 Gy/fraction to total dose of 74 Gy͒ were the highest among analyzed treatment techniques. The average NTCP for the rectum and urethra were 0.6% and 24.7% for LDR-BT and 0.5% and 11.2% for HDR-BT. Conclusions: Although brachytherapy techniques resulted in delivering larger equivalent doses to normal tissues, the corresponding NTCPs were lower than those of external beam techniques other than the urethra because of much smaller volumes irradiated to higher doses. Among analyzed normal tissues, the femoral heads were found to have the lowest probability of complications as most of their volume was irradiated to lower equivalent doses compared to other tissues.
The British Journal of Radiology, 2016
Barbara Alicja Jereczek-Fossa and Delia Ciardo contributed equally to this study. Objective: To compare the toxicity of image-guided intensity-modulated radiotherapy (IG-IMRT) to the pelvis or prostate bed (PB) only. To test the hypothesis that the potentially injurious effect of pelvic irradiation can be counterbalanced by reduced irradiated normal tissue volume using IG-IMRT. Methods: Between February 2010 and February 2012, 208 patients with prostate cancer were treated with adjuvant or salvage IG-IMRT to the PB (102 patients, Group PB) or the pelvis and prostate bed (P) (106 patients, Group P). The Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria were used to evaluate toxicity. Results: Median follow-up was 27 months. Toxicity G $ 2 in Group PB: in the bowel acute and late toxicities were 11.8% and 10%, respectively; urinary acute and late toxicities were 10.8% and 15%, respectively. Toxicity G $ 2 in Group P: in the bowel acute and late toxicities were both 13.2%; urinary acute and late toxicities were 13.2% and 15.1%, respectively. No statistical difference in acute or late toxicity between the groups was found (bowel: p 5 0.23 and p 5 0.89 for acute and late toxicity, respectively; urinary: p 5 0.39 and p 5 0.66 for acute and late toxicity, respectively). Of the clinical variables, only previous abdominal surgery was correlated with acute bowel toxicity. Dosimetric parameters that correlated with bowel toxicity were identified. Conclusion: The toxicity rates were low and similar in both groups, suggesting that IG-IMRT allows for a safe post-operative irradiation of larger volumes. Further investigation is warranted to exclude bias owing to nonrandomized character of the study. Advances in knowledge: Our report shows that modern radiotherapy technology and careful planning allow maintaining the toxicity of pelvic lymph node treatment at the acceptable level, as it is in the case of PB radiotherapy.