| 1. |
- Thor, M., et al.
(författare)
-
Inter-institutional analysis demonstrates the importance of lower than previously anticipated dose regions to prevent late rectal bleeding following prostate radiotherapy
- 2018
-
Ingår i: Radiotherapy and Oncology. - : Elsevier BV. - 0167-8140. ; 127:1, s. 88-95
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: To investigate whether inter-institutional cohort analysis uncovers more reliable dose-response relationships exemplified for late rectal bleeding (LRB) following prostate radiotherapy. Material and methods: Data from five institutions were used. Rectal dose-volume histograms (DVHs) for 989 patients treated with 3DCRT or IMRT to 70-86.4 Gy@1.8-2.0 Gy/fraction were obtained, and corrected for fractionation effects (alpha/beta = 3 Gy). Cohorts with best-fit Lyman-Kutcher-Burman volume-effect parameter a were pooled after calibration adjustments of the available LRB definitions. In the pooled cohort, dose-response modeling (incorporating rectal dose and geometry, and patient characteristics) was conducted on a training cohort (70%) followed by final testing on the remaining 30%. Multivariate logistic regression was performed to build models with bootstrap stability. Results: Two cohorts with low bleeding rates (2%) were judged to be inconsistent with the remaining data, and were excluded. In the remaining pooled cohorts (n = 690; LRB rate = 12%), an optimal model was generated for 3DCRT using the minimum rectal dose and the absolute rectal volume receiving less than 55 Gy (AUC = 0.67; p = 0.0002; Hosmer-Lemeshow p-value, p(HL) = 0.59). The model performed nearly as well in the hold-out testing data (AUC = 0.71; p < 0.0001; p(HL) = 0.63), indicating a logistically shaped dose-response. Conclusion: We have demonstrated the importance of integrating datasets from multiple institutions, thereby reducing the impact of intra-institutional dose-volume parameters explicitly correlated with prescription dose levels. This uncovered an unexpected emphasis on sparing of the low to intermediate rectal dose range in the etiology of late rectal bleeding following prostate radiotherapy. (C) 2018 Elsevier B. V. All rights reserved. Radiotherapy and Oncology 127 (2018) 88-95
|
|
| 2. |
- Wibmer, A. G., et al.
(författare)
-
Oncologic Outcomes after Localized Prostate Cancer Treatment: Associations with Pretreatment Prostate Magnetic Resonance Imaging Findings
- 2021
-
Ingår i: Journal of Urology. - : Ovid Technologies (Wolters Kluwer Health). - 0022-5347 .- 1527-3792. ; 205:4, s. 1055-1062
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: We investigated whether T2-weighted magnetic resonance imaging findings could improve upon established prognostic indicators of metastatic disease and prostate cancer specific survival. Materials and Methods: For a cohort of 3,406 consecutive men who underwent prostate magnetic resonance imaging before prostatectomy (2,160) or radiotherapy (1,246) between 2001 and 2006, T2-weighted magnetic resonance imaging exams were retrospectively interpreted and categorized as I) no focal suspicious lesion, II) organ confined focal lesion, III) focal lesion with extraprostatic extension or IV) focal lesion with seminal vesicle invasion. Clinical risk was recorded based on European Association of Urology (EAU) guidelines and the Cancer of the Prostate Risk Assessment (CAPRA) scoring system. Survival probabilities and c-indices were estimated using Cox models and inverse probability censoring weights, respectively. Results: The median followup was 10.8 years (IQR 8.6-13.0). Higher magnetic resonance imaging categories were associated with a higher likelihood of developing metastases (HR 3.5-18.1, p<0.001 for all magnetic resonance imaging categories) and prostate cancer death (HR 3.1-29.7, p<0.001-0.025); these associations were statistically independent of EAU risk categories, CAPRA scores and treatment type (surgery vs radiation). Combining EAU risk or CAPRA scores with magnetic resonance imaging categories significantly improved prognostication of metastases (c-indices: EAU: 0.798, EAU + magnetic resonance imaging: 0.872; CAPRA: 0.808, CAPRA + magnetic resonance imaging: 0.877) and prostate cancer death (c-indices: EAU 0.813, EAU + magnetic resonance imaging: 0.889; CAPRA: 0.814, CAPRA + magnetic resonance imaging: 0.892; p<0.001 for all). Conclusion: Magnetic resonance imaging findings of localized prostate cancer are associated with clinically relevant long-term oncologic outcomes. Combining magnetic resonance imaging and clinicopathological data results in more accurate prognostication, which could facilitate individualized patient management.
|
|
