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RapidArc, intensity modulated photon and proton techniques for recurrent prostate cancer in previously irradiated patients: a treatment planning comparison study.

Weber DC, Wang H, Cozzi L, Dipasquale G, Khan HG, Ratib O, Rouzaud M, Vees H, Zaidi H, Miralbell R - Radiat Oncol (2009)

Bottom Line: CI90 was 1.3 +/- 0.1 for photons and 1.6 +/- 0.2 for protons.Integral Dose was 1.1 +/- 0.5 Gy*cm3 *105 for IMPT and about a factor three higher for all photon's techniques.IMPT showed further sparing of organs at risk.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Radiation Oncology, University Hospital of Geneva, Geneva, Switzerland. damien.weber@hcuge.ch

ABSTRACT

Background: A study was performed comparing volumetric modulated arcs (RA) and intensity modulation (with photons, IMRT, or protons, IMPT) radiation therapy (RT) for patients with recurrent prostate cancer after RT.

Methods: Plans for RA, IMRT and IMPT were optimized for 7 patients. Prescribed dose was 56 Gy in 14 fractions. The recurrent gross tumor volume (GTV) was defined on 18F-fluorocholine PET/CT scans. Plans aimed to cover at least 95% of the planning target volume with a dose > 50.4 Gy. A maximum dose (DMax) of 61.6 Gy was allowed to 5% of the GTV. For the urethra, DMax was constrained to 37 Gy. Rectal DMedian was < 17 Gy. Results were analyzed using Dose-Volume Histogram and conformity index (CI90) parameters.

Results: Tumor coverage (GTV and PTV) was improved with RA (V95% 92.6 +/- 7.9 and 83.7 +/- 3.3%), when compared to IMRT (V95% 88.6 +/- 10.8 and 77.2 +/- 2.2%). The corresponding values for IMPT were intermediate for the GTV (V95% 88.9 +/- 10.5%) and better for the PTV (V95%85.6 +/- 5.0%). The percentages of rectal and urethral volumes receiving intermediate doses (35 Gy) were significantly decreased with RA (5.1 +/- 3.0 and 38.0 +/- 25.3%) and IMPT (3.9 +/- 2.7 and 25.1 +/- 21.1%), when compared to IMRT (9.8 +/- 5.3 and 60.7 +/- 41.7%). CI90 was 1.3 +/- 0.1 for photons and 1.6 +/- 0.2 for protons. Integral Dose was 1.1 +/- 0.5 Gy*cm3 *105 for IMPT and about a factor three higher for all photon's techniques.

Conclusion: RA and IMPT showed improvements in conformal avoidance relative to fixed beam IMRT for 7 patients with recurrent prostate cancer. IMPT showed further sparing of organs at risk.

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GTV in the axial (A), coronal (B) and sagital (C) simulation CT with PET fusion and 18F-choline PET slice, respectively.
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Figure 1: GTV in the axial (A), coronal (B) and sagital (C) simulation CT with PET fusion and 18F-choline PET slice, respectively.

Mentions: The institutional 18F-Choline database containing 47 prostate cancer patients was queried to identify individuals with: 1) biochemically recurrence; 2) local relapse only; 3) previous high-dose (≥ 70 Gy) RT and 4) endorectal MRI. Seven of such patients were identified (median age, 77 years; Table 1). They all underwent previous curative 3D conformal RT (median dose, 74 Gy; HDR brachytherapy boost 14 Gy in 2 fractions, 2 patients), 4.8 to 7.6 (median, 5.9) years before biological recurrence (Table 1). The median dose received by 50%/1% of the rectum and bladder by this prior treatment were 44.1 (range, 60.0 - 38.5)/71.0 (range, 74.5 - 62.4) and 59.0 (range, 67.2 - 43.4)/74.0 (range, 78.0 - 64.4) Gy, respectively. The median rectal volume receiving 35 Gy was 79.4%, and range from 56.0 to 96.0%. Local relapse was proven by PET-CT examination with 18F-choline; failures were confirmed by sextant biopsy in all but one patient. A positive correlation between 18F-choline uptake and the location of the histological proven recurrence was observed in all 6 patients. Table 2 details the radiological and pathological correlation of these recurrences. PET/CT imaging was performed on the Biograph 16 scanner (Siemens Medical Solution, Erlangen, Germany) operating in 3D mode (Fig. 1). An endorectal MRI, with spectroscopy and contrast enhancement, was acquired for all patients [10]. The main organs at risk (OARs) considered for all patients were the urethra (defined on the base of MR imaging and verified by an experienced radiologist), bladder, rectum, penile bulb and femoral heads The non-target tissue was defined as the patient's volume covered by the CT scan minus the planning target volume (PTV).


RapidArc, intensity modulated photon and proton techniques for recurrent prostate cancer in previously irradiated patients: a treatment planning comparison study.

Weber DC, Wang H, Cozzi L, Dipasquale G, Khan HG, Ratib O, Rouzaud M, Vees H, Zaidi H, Miralbell R - Radiat Oncol (2009)

GTV in the axial (A), coronal (B) and sagital (C) simulation CT with PET fusion and 18F-choline PET slice, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2749024&req=5

Figure 1: GTV in the axial (A), coronal (B) and sagital (C) simulation CT with PET fusion and 18F-choline PET slice, respectively.
Mentions: The institutional 18F-Choline database containing 47 prostate cancer patients was queried to identify individuals with: 1) biochemically recurrence; 2) local relapse only; 3) previous high-dose (≥ 70 Gy) RT and 4) endorectal MRI. Seven of such patients were identified (median age, 77 years; Table 1). They all underwent previous curative 3D conformal RT (median dose, 74 Gy; HDR brachytherapy boost 14 Gy in 2 fractions, 2 patients), 4.8 to 7.6 (median, 5.9) years before biological recurrence (Table 1). The median dose received by 50%/1% of the rectum and bladder by this prior treatment were 44.1 (range, 60.0 - 38.5)/71.0 (range, 74.5 - 62.4) and 59.0 (range, 67.2 - 43.4)/74.0 (range, 78.0 - 64.4) Gy, respectively. The median rectal volume receiving 35 Gy was 79.4%, and range from 56.0 to 96.0%. Local relapse was proven by PET-CT examination with 18F-choline; failures were confirmed by sextant biopsy in all but one patient. A positive correlation between 18F-choline uptake and the location of the histological proven recurrence was observed in all 6 patients. Table 2 details the radiological and pathological correlation of these recurrences. PET/CT imaging was performed on the Biograph 16 scanner (Siemens Medical Solution, Erlangen, Germany) operating in 3D mode (Fig. 1). An endorectal MRI, with spectroscopy and contrast enhancement, was acquired for all patients [10]. The main organs at risk (OARs) considered for all patients were the urethra (defined on the base of MR imaging and verified by an experienced radiologist), bladder, rectum, penile bulb and femoral heads The non-target tissue was defined as the patient's volume covered by the CT scan minus the planning target volume (PTV).

Bottom Line: CI90 was 1.3 +/- 0.1 for photons and 1.6 +/- 0.2 for protons.Integral Dose was 1.1 +/- 0.5 Gy*cm3 *105 for IMPT and about a factor three higher for all photon's techniques.IMPT showed further sparing of organs at risk.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Radiation Oncology, University Hospital of Geneva, Geneva, Switzerland. damien.weber@hcuge.ch

ABSTRACT

Background: A study was performed comparing volumetric modulated arcs (RA) and intensity modulation (with photons, IMRT, or protons, IMPT) radiation therapy (RT) for patients with recurrent prostate cancer after RT.

Methods: Plans for RA, IMRT and IMPT were optimized for 7 patients. Prescribed dose was 56 Gy in 14 fractions. The recurrent gross tumor volume (GTV) was defined on 18F-fluorocholine PET/CT scans. Plans aimed to cover at least 95% of the planning target volume with a dose > 50.4 Gy. A maximum dose (DMax) of 61.6 Gy was allowed to 5% of the GTV. For the urethra, DMax was constrained to 37 Gy. Rectal DMedian was < 17 Gy. Results were analyzed using Dose-Volume Histogram and conformity index (CI90) parameters.

Results: Tumor coverage (GTV and PTV) was improved with RA (V95% 92.6 +/- 7.9 and 83.7 +/- 3.3%), when compared to IMRT (V95% 88.6 +/- 10.8 and 77.2 +/- 2.2%). The corresponding values for IMPT were intermediate for the GTV (V95% 88.9 +/- 10.5%) and better for the PTV (V95%85.6 +/- 5.0%). The percentages of rectal and urethral volumes receiving intermediate doses (35 Gy) were significantly decreased with RA (5.1 +/- 3.0 and 38.0 +/- 25.3%) and IMPT (3.9 +/- 2.7 and 25.1 +/- 21.1%), when compared to IMRT (9.8 +/- 5.3 and 60.7 +/- 41.7%). CI90 was 1.3 +/- 0.1 for photons and 1.6 +/- 0.2 for protons. Integral Dose was 1.1 +/- 0.5 Gy*cm3 *105 for IMPT and about a factor three higher for all photon's techniques.

Conclusion: RA and IMPT showed improvements in conformal avoidance relative to fixed beam IMRT for 7 patients with recurrent prostate cancer. IMPT showed further sparing of organs at risk.

Show MeSH
Related in: MedlinePlus