Dosimetric Impact and Theoretical Clinical Benefits of Fiducial Markers for Dose Escalated Prostate Cancer Radiation Treatment

Journal Article · Wed Jul 15 04:00:00 EDT 2009 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2008.09.043· OSTI ID:21276906

Gauthier, Isabelle ^[1]; Carrier, Jean-Francois; Beliveau-Nadeau, Dominic; Fortin, Bernard; Taussky, Daniel ^[1]

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1. Departement de Radio-Oncologie, Centre Hospitalier de l'Universite de Montreal - Hopital Notre-Dame, Montreal, Quebec (Canada)

Purpose: To assess the impact of fiducial markers and daily kilovoltage imaging (FM-kV) on dose-volume histogram (DVH) parameters and normal tissue complication probabilities (NTCPs) for the rectum and bladder during prostate cancer radiotherapy. Methods and Materials: Two different setup scenarios were compared for 20 patients treated with three-dimensional conformal radiotherapy (3D-CRT) for localized prostate cancer to a total dose of 76 Gy: a traditional setup with planning target volume (PTV) margins associated with skin mark alignment vs. another setup using FM-kV. Various DVH parameters were compared, including Radiation Therapy Oncology Group (RTOG) dose-volume constraints for the rectum and bladder. Analysis of NTCPs was also performed according to the Lyman model. Results: With the traditional setup, 85% of patients had rectal V70{sub Gy} >25% compared with 45% with FM-kV. Moreover, 30% of patients with traditional setup vs. 5% with FM-kV did not fulfill at least 3 RTOG constraint parameters for the rectum. Mean rectal and bladder dose were 4.7 Gy and 6.7 Gy less, respectively, with FM-kV. The NTCP for the rectum was 11.5% with the traditional setup and 9% with FM-kV. This indicates that with FM-kV, the prescription dose could be increased by 2.1 Gy while keeping the same level of late rectal toxicity as with the traditional setup. Conclusions: Use of FM-kV is an efficient way of lowering the proportion of patients not fulfilling RTOG rectal and bladder dose-volume constraints. The results of the NTCP analysis suggest that the PTV margin reduction allowed by FM-kV should decrease the rate of late rectal toxicities or may allow moderate dose escalation.

• OSTI ID: 21276906
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 4 Vol. 74; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BLADDER
NEOPLASMS
PATIENTS
PLANNING
PROSTATE
RADIATION DOSES
RADIOTHERAPY
RECTUM
SKIN
TOXICITY