Modeling normal tissue complication probability from repetitive computed tomography scans during fractionated high-dose-rate brachytherapy and external beam radiotherapy of the uterine cervix
(2000) In International Journal of Radiation Oncology, Biology, Physics 47(4). p.963-971- Abstract
PURPOSE: To calculate the normal tissue complication probability (NTCP) of late radiation effects on the rectum and bladder from repetitive CT scans during fractionated high-dose-rate brachytherapy (HDRB) and external beam radiotherapy (EBRT) of the uterine cervix and compare the NTCP with the clinical frequency of late effects.
METHODS AND MATERIALS: Fourteen patients with cancer of the uterine cervix (Stage IIb-IVa) underwent 3-6 (mean, 4.9) CT scans in treatment position during their course of HDRB using a ring applicator with an Iridium stepping source. The rectal and bladder walls were delineated on the treatment-planning system, such that a constant wall volume independent of organ filling was achieved. Dose-volume... (More)
PURPOSE: To calculate the normal tissue complication probability (NTCP) of late radiation effects on the rectum and bladder from repetitive CT scans during fractionated high-dose-rate brachytherapy (HDRB) and external beam radiotherapy (EBRT) of the uterine cervix and compare the NTCP with the clinical frequency of late effects.
METHODS AND MATERIALS: Fourteen patients with cancer of the uterine cervix (Stage IIb-IVa) underwent 3-6 (mean, 4.9) CT scans in treatment position during their course of HDRB using a ring applicator with an Iridium stepping source. The rectal and bladder walls were delineated on the treatment-planning system, such that a constant wall volume independent of organ filling was achieved. Dose-volume histograms (DVH) of the rectal and bladder walls were acquired. A method of summing multiple DVHs accounting for variable dose per fraction were applied to the DVHs of HDRB and EBRT together with the Lyman-Kutcher NTCP model fitted to clinical dose-volume tolerance data from recent studies.
RESULTS: The D(mean) of the DVH from EBRT was close to the D(max) for both the rectum and bladder, confirming that the DVH from EBRT corresponded with homogeneous whole-organ irradiation. The NTCP of the rectum was 19.7% (13.5%, 25. 9%) (mean and 95% confidence interval), whereas the clinical frequency of late rectal sequelae (Grade 3-4, RTOG/EORTC) was 13% based on material from 200 patients. For the bladder the NTCP was 61. 9% (46.8%, 76.9%) as compared to the clinical frequency of Grade 3-4 late effects of 14%. If only 1 CT scan from HDRB was assumed available, the relative uncertainty (standard deviation or SD) of the NTCP value for an arbitrary patient was 20-30%, whereas 4 CT scans provided an uncertainty of 12-13%.
CONCLUSION: The NTCP for the rectum was almost consistent with the clinical frequency of late effects, whereas the NTCP for bladder was too high. To obtain reliable (SD of 12-13%) NTCP values, 3-4 CT scans are needed during 5-7 fractions of HDRB treatments.
(Less)
- author
- Dale, Einar ; Hellebust, T P ; Skjønsberg, A ; Høgberg, T LU and Olsen, D R
- publishing date
- 2000-07-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Algorithms, Brachytherapy/adverse effects, Confidence Intervals, Dose Fractionation, Radiation, Female, Humans, Probability, Radiation Injuries/diagnostic imaging, Radiotherapy, Computer-Assisted/methods, Rectal Diseases/diagnostic imaging, Rectum/diagnostic imaging, Reproducibility of Results, Tomography, X-Ray Computed, Urinary Bladder/diagnostic imaging, Urinary Bladder Diseases/diagnostic imaging, Uterine Cervical Neoplasms/diagnostic imaging
- in
- International Journal of Radiation Oncology, Biology, Physics
- volume
- 47
- issue
- 4
- pages
- 963 - 971
- publisher
- Elsevier
- external identifiers
-
- pmid:10863066
- scopus:0034237690
- ISSN
- 0360-3016
- DOI
- 10.1016/s0360-3016(00)00510-1
- language
- English
- LU publication?
- no
- id
- f84b9673-4f53-4a21-af2c-d1c9edd1a317
- date added to LUP
- 2019-09-20 07:59:40
- date last changed
- 2024-01-01 20:54:32
@article{f84b9673-4f53-4a21-af2c-d1c9edd1a317,
abstract = {{<p>PURPOSE: To calculate the normal tissue complication probability (NTCP) of late radiation effects on the rectum and bladder from repetitive CT scans during fractionated high-dose-rate brachytherapy (HDRB) and external beam radiotherapy (EBRT) of the uterine cervix and compare the NTCP with the clinical frequency of late effects.</p><p>METHODS AND MATERIALS: Fourteen patients with cancer of the uterine cervix (Stage IIb-IVa) underwent 3-6 (mean, 4.9) CT scans in treatment position during their course of HDRB using a ring applicator with an Iridium stepping source. The rectal and bladder walls were delineated on the treatment-planning system, such that a constant wall volume independent of organ filling was achieved. Dose-volume histograms (DVH) of the rectal and bladder walls were acquired. A method of summing multiple DVHs accounting for variable dose per fraction were applied to the DVHs of HDRB and EBRT together with the Lyman-Kutcher NTCP model fitted to clinical dose-volume tolerance data from recent studies.</p><p>RESULTS: The D(mean) of the DVH from EBRT was close to the D(max) for both the rectum and bladder, confirming that the DVH from EBRT corresponded with homogeneous whole-organ irradiation. The NTCP of the rectum was 19.7% (13.5%, 25. 9%) (mean and 95% confidence interval), whereas the clinical frequency of late rectal sequelae (Grade 3-4, RTOG/EORTC) was 13% based on material from 200 patients. For the bladder the NTCP was 61. 9% (46.8%, 76.9%) as compared to the clinical frequency of Grade 3-4 late effects of 14%. If only 1 CT scan from HDRB was assumed available, the relative uncertainty (standard deviation or SD) of the NTCP value for an arbitrary patient was 20-30%, whereas 4 CT scans provided an uncertainty of 12-13%.</p><p>CONCLUSION: The NTCP for the rectum was almost consistent with the clinical frequency of late effects, whereas the NTCP for bladder was too high. To obtain reliable (SD of 12-13%) NTCP values, 3-4 CT scans are needed during 5-7 fractions of HDRB treatments.</p>}},
author = {{Dale, Einar and Hellebust, T P and Skjønsberg, A and Høgberg, T and Olsen, D R}},
issn = {{0360-3016}},
keywords = {{Algorithms; Brachytherapy/adverse effects; Confidence Intervals; Dose Fractionation, Radiation; Female; Humans; Probability; Radiation Injuries/diagnostic imaging; Radiotherapy, Computer-Assisted/methods; Rectal Diseases/diagnostic imaging; Rectum/diagnostic imaging; Reproducibility of Results; Tomography, X-Ray Computed; Urinary Bladder/diagnostic imaging; Urinary Bladder Diseases/diagnostic imaging; Uterine Cervical Neoplasms/diagnostic imaging}},
language = {{eng}},
month = {{07}},
number = {{4}},
pages = {{963--971}},
publisher = {{Elsevier}},
series = {{International Journal of Radiation Oncology, Biology, Physics}},
title = {{Modeling normal tissue complication probability from repetitive computed tomography scans during fractionated high-dose-rate brachytherapy and external beam radiotherapy of the uterine cervix}},
url = {{http://dx.doi.org/10.1016/s0360-3016(00)00510-1}},
doi = {{10.1016/s0360-3016(00)00510-1}},
volume = {{47}},
year = {{2000}},
}