Dose escalation with three-dimensional conformal radiation therapy affects the outcome in prostate cancer

Zeléfsky, Michael J.; Leibel, Steven A.; Gaudin, Paul B.; Kutcher, Gerald J.; Fleshner, Neil; Venkatramen, E. S.; Reuter, Victor E.; Fair, William R.; Ling, C. Clifton; Fuks, Zvi

doi:10.1016/s0360-3016(98)00091-1

Cited by 846 publications

(336 citation statements)

References 67 publications

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“…Experience with conformal radiotherapy (CRT) for prostate cancer treatment has shown that reducing normal tissue irradiation leads to lower rates of gastrointestinal (GI) and genitourinary (GU) normal tissue toxicity (1)(2)(3)(4). This has spurred efforts to achieve further sparing of organs at risk (OARs) to allow for dose escalation, in particular with the introduction of intensity-modulated radiotherapy (IMRT).…”

Section: Introductionmentioning

confidence: 99%

“…Patients with distant metastases were excluded if positive findings were present in the routine bone scan. All patients were at high risk according to the criteria of Zelefsky et al (2) and were given endocrine therapy consisting of a 6-months course of luteinizing hormone-releasing hormone analogue and antiandrogen (maximal androgen blockade). Endocrine therapy commenced 2 to 3 months post-RT to exploit the reduction of the prostate volume, and continued 3 to 4 months after the start of RT (18).…”

Section: Introductionmentioning

confidence: 99%

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Intensity-Modulated Radiotherapy of Pelvic Lymph Nodes in Locally Advanced Prostate Cancer: Planning Procedures and Early Experiences

Muren

Wasbø

Helle

et al. 2008

International Journal of Radiation Oncology*Biology*Physics

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Purpose: We present planning and early clinical outcomes of a study of intensity-modulated radiotherapy (IMRT) for locally advanced prostate cancer. Methods and Materials: A total of 43 patients initially treated with an IMRT plan delivering 50 Gy to the prostate, seminal vesicles, and pelvic lymph nodes, followed by a conformal radiotherapy (CRT) plan delivering 20 Gy to the prostate and seminal vesicles, were studied. Dose-volume histogram (DVH) data for the added plans were compared with dose-volume histogram data for the sum of two CRT plans for 15 cases. Gastrointestinal (GI) and genitourinary (GU) toxicity, based on the Radiation Therapy Oncology Group scoring system, was recorded weekly throughout treatment as well as 3 to 18 months after treatment and are presented. Results: Treatment with IMRT both reduced normal tissue doses and increased the minimum target doses. Intestine volumes receiving more than 40 and 50 Gy were significantly reduced (e.g., at 50 Gy, from 81 to 19 cm 3 ; p = 0.026), as were bladder volumes above 40, 50, and 60 Gy, rectum volumes above 30, 50, and 60 Gy, and hip joint muscle volumes above 20, 30, and 40 Gy. During treatment, Grade 2 GI toxicity was reported by 12 of 43 patients (28%), and Grade 2 to 4 GU toxicity was also observed among 12 patients (28%). With 6 to 18 months of follow-up, 2 patients (5%) experienced Grade 2 GI effects and 7 patients (16%) experienced Grade 2 GU effects. Conclusions: Use of IMRT for pelvic irradiation in prostate cancer reduces normal tissue doses, improves target coverage, and has a promising toxicity profile. Ó

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Intensity-Modulated Radiotherapy of Pelvic Lymph Nodes in Locally Advanced Prostate Cancer: Planning Procedures and Early Experiences

Muren

Wasbø

Helle

et al. 2008

International Journal of Radiation Oncology*Biology*Physics

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“…There appears to be a certain degree of variation among cancer centers regarding the prostate PTV definition. ( 1 – 6 ) Commonly, the margin is approximately 1 cm with a smaller posterior margin to achieve better rectal sparing. A more generic approach has been suggested by van Herk, (7) who proposed linking the PTV margin with systematic and random errors.…”

Section: Introductionmentioning

confidence: 99%

PTV margin for dose‐escalated radiation therapy of prostate cancer with daily online realignment using internal fiducial markers: Monte Carlo approach and dose population histogram (DPH) analysis

Zhang

Moiseenko

Liu

2006

J Applied Clin Med Phys

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Using internal fiducial markers and electronic portal imaging (EPI) to realign patients has been shown to significantly reduce positioning uncertainties in prostate radiation treatment. This creates the possibility of decreasing the planning target volume (PTV) margin added on the clinical target volume (CTV), which in turn may allow for dose escalation. We compared the outcome of two plans: 70 Gy/35 fx, 10‐mm PTV margin without patient realignment (Reference Plan) and 78 Gy/39 fx, 5‐mm PTV margin with patient realignment (Escalated Plan). Four‐field‐oblique (gantry angles 35°, 90°, 270°, 325°) beam arrangement was used. Monte Carlo code was used to simulate the daily organ motion. Dose to each organ was calculated. Tumor control probability (TCP) and the effective dose to critical organs false(Defffalse) were calculated using the biologically normalized dose‐volume histograms. By comparing the biological factors, we found that the prescription dose can be escalated to 78 Gy/39 fx with a 5‐mm PTV margin when using internal fiducial markers and EPI. Based on the available dose‐response data for intermediate risk prostate patients, this will result in a 20% increase of local control and significantly reduced rectal complications provided that less serial dose‐volume behavior of rectum is proven.PACS number: 87.50.‐a

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“…( 1 , 2 ) As compared with conventional radiotherapy, advanced radiotherapy techniques are designed to achieve prostate dose escalation while reducing side effects. Three‐dimensional conformal radiation therapy (3D‐CRT) facilitates prostate dose escalation and achieves higher disease‐free survival, ( 3 , 4 ) comparable or lower acute toxicity, ( 4 – 6 ) and lower late morbidity. ( 6 , 7 ) The optimized 3D‐CRT plan can be achieved by proper choice of the number and orientations of conformal beams.…”

Section: Introductionmentioning

confidence: 99%

Forward‐planning intensity‐modulated radiotherapy technique for prostate cancer

Metwaly

Awaad

El-Sayed

et al. 2007

J Applied Clin Med Phys

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In this study, we present an intensity‐modulated radiotherapy technique based on forward planning dose calculations to provide a concave dose distribution to the prostate and seminal vesicles by means of modified dynamic arc therapy (M‐DAT). Dynamic arcs (350 degrees) conforming to the beam's eye view of the prostate and seminal vesicles while shielding the rectum, combined with two lateral oblique conformal fields (15 degrees with respect to laterals) fitting the prostate only, were applied to deliver doses of 78 Gy and 61.23 Gy in 39 fractions to the prostate and seminal vesicles respectively. Dynamic wedges (45 degrees of thick end, anteriorly oriented) were used with conformal beams to adjust the dose homogeneity to the prostate, although in some cases, hard wedges (30 degrees of thick part, inferiorly oriented) were used with arcs to adjust the dose coverage to the seminal vesicles. The M‐DAT was applied to 10 patients in supine and 10 patients in prone positioning to determine the proper patient positioning for optimum protection of the rectum. The M‐DAT was compared with the simplified intensity‐modulated arc therapy (SIMAT) technique, composed of three phases of bilateral dynamic arcs. The mean rectal dose in M‐DAT for prone patients was 22.5±5.1 Gy; in M‐DAT and SIMAT for supine patients, it was 30.2±5.1 Gy and 39.4±6.0 Gy respectively. The doses to 15%, 25%, 35%, and 50% of the rectum volume in M‐DAT for prone patients were 44.5±10.2 Gy, 33.0±8.2 Gy, 25.3±6.4 Gy, and 16.3±5.6 Gy respectively. These values were lower than those in M‐DAT and in SIMAT for supine patients by 7.7%, 18.2%, 22.4%, and 28.5% and by 25.0%, 32.1%, 34.9%, and 41.9% of the prescribed dose (78 Gy) respectively. Ion chamber measurements showed good agreement of the calculated and measured isocentric dose (maximum deviation of 3.5%). Accuracy of the dose distribution calculation was evaluated by film dosimetry using a gamma index, allowing 3% dose variation and 4 mm distance to agreement as the individual acceptance criteria in prostate and seminal vesicle levels alike for all supine and prone patients. We found that fewer than 10% of the pixels in the dose distribution of the calculated area of 10×10−cm failed the acceptance criteria. These pixels were observed mainly in the low‐dose regions, particularly at the level of the seminal vesicles.In conclusion, the single‐phase M‐DAT technique with patients in the prone position was found to provide the intended coverage of the prescribed doses to the prostate and seminal vesicles with improved protection for the rectum. Accordingly, M‐DAT has replaced non‐modulated conformal radiotherapy or SIMAT as the standard treatment for prostate cancer in our department.PACS number: 87.53.Tf

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Dose escalation with three-dimensional conformal radiation therapy affects the outcome in prostate cancer

Cited by 846 publications

References 67 publications

Intensity-Modulated Radiotherapy of Pelvic Lymph Nodes in Locally Advanced Prostate Cancer: Planning Procedures and Early Experiences

Intensity-Modulated Radiotherapy of Pelvic Lymph Nodes in Locally Advanced Prostate Cancer: Planning Procedures and Early Experiences

PTV margin for dose‐escalated radiation therapy of prostate cancer with daily online realignment using internal fiducial markers: Monte Carlo approach and dose population histogram (DPH) analysis

Forward‐planning intensity‐modulated radiotherapy technique for prostate cancer

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