An IGRT margin concept for pelvic lymph nodes in high-risk prostate cancer

Groher, Michael E.; Kopp, Peter; Drerup, Martin; Deutschmann, H.; Sedlmayer, Felix; Wolf, Frank

doi:10.1007/s00066-017-1182-1

Cited by 9 publications

(6 citation statements)

References 23 publications

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“…The combination of high-dose RT and systemic treatment reduces the number of PCa cells in the prostate and pelvic lymph nodes (34). Active lesions can be precisely detected with MRI, 18 F-sodium fluoride (Na 18 F), 18 F-fluoromethylcholine ( 18 F-FCH), and 68 gallium- and prostate-specific membrane antigen-labeled PET/CT ( 68 Ga-PSMA-PET-CT) (35–37). PET/CT tracers for PCa such as 11 C-acetate, 11 C-choline and 18 F-choline were developed more than a decade ago; nevertheless, these tracers are still being studied to verify their reliability as imaging tools to determine disease extension in patients who develop early biochemical failure (38–40).…”

Section: Overview Of Pca Imaging Methodsmentioning

confidence: 99%

Liquid Biopsy in Oligometastatic Prostate Cancer—A Biologist's Point of View

et al. 2019

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Prostate cancer (PCa) is the main cause of cancer-related mortality in males and the diagnosis, treatment, and care of these patients places a great burden on healthcare systems globally. Clinically, PCa is highly heterogeneous, ranging from indolent tumors to highly aggressive disease. In many cases treatment—generally either radiotherapy (RT) or surgery—can be curative. Several key genetic and demographic factors such as age, family history, genetic susceptibility, and race are associated with a high incidence of PCa. While our understanding of PCa, which is mainly based on the tools of molecular biology—has improved dramatically in recent years, efforts to better understand this complex disease have led to the identification of a new type of PCa–oligometastatic PCa. Oligometastatic disease should be considered an individual, heterogeneous entity with distinct metastatic phenotypes and, consequently, wide prognostic variability. In general, patients with oligometastatic disease typically present less biologically aggressive tumors whose metastatic potential is more limited and which are slow-growing. These patients are good candidates for more aggressive treatment approaches. The main aim of the presented review was to evaluate the utility of liquid biopsy for diagnostic purposes in PCa and for use in monitoring disease progression and treatment response, particularly in patients with oligometastatic PCa. Liquid biopsies offer a rapid, non-invasive approach whose use t is expected to play an important role in routine clinical practice to benefit patients. However, more research is needed to resolve the many existing discrepancies with regard to the definition and isolation method for specific biomarkers, as well as the need to determine the most appropriate markers. Consequently, the current priority in this field is to standardize liquid biopsy-based techniques. This review will help to improve understanding of the biology of PCa, particularly the recently defined condition known as “oligometastatic PCa”. The presented review of the body of evidence suggests that additional research in molecular biology may help to establish novel treatments for oligometastatic PCa. In the near future, the treatment of PCa will require an interdisciplinary approach involving active cooperation among clinicians, physicians, and biologists.

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Section: Overview Of Pca Imaging Methodsmentioning

confidence: 99%

Liquid Biopsy in Oligometastatic Prostate Cancer—A Biologist's Point of View

et al. 2019

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“…However, expanding the irradiated volume consequently increases normal organ toxicity, which is limited by the tolerances of the bladder and rectum [8, 13]. In recent years, advances in image guidance have allowed for better localization of the prostate [14–20]. Using image guidance together with IMRT delivers the dose to the prostate more precisely with smaller margins to decrease the doses to the rectum and bladder.…”

Section: Introductionmentioning

confidence: 99%

Retrospective study comparing MR-guided radiation therapy (MRgRT) setup strategies for prostate treatment: repositioning vs. replanning

Kim

Choi

et al. 2019

Radiat Oncol

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Background This study compared adaptive replanning and repositioning corrections based on soft-tissue matching for prostate cancer by using the magnetic resonance-guided radiation therapy (MRgRT) system. Methods A total of 19 patients with prostate cancer were selected retrospectively. Weekly magnetic resonance image (MRI) scans were acquired for 5 weeks for each patient to observe the anatomic changes during the treatment course. Initial intensity-modulated radiation therapy (IMRT) plans (iIMRT) were generated for each patient with 13 coplanar 60 Co beams on a ViewRay™ system. Two techniques were applied: patient repositioning and replanning. For patient repositioning, one plan was created: soft-tissue (prostate) matching ( Soft ). The dose distribution was calculated for each MRI with the beam delivery parameters from the initial IMRT plan. The replanning technique was used to generate the Adaptive plan, which was the reoptimized plan for the weekly MRI. The dose-volumetric parameters of the planning target volume (PTV), bladder, and rectum were calculated for all plans. During the treatment course, the PTV, bladder, and rectum were evaluated for changes in volume and the effect on dosimetric parameters. The differences between the dose-volumetric parameters of the plans were examined through the Wilcoxon test. The initial plan was used as a baseline to compare the differences. Results The Adaptive plan showed better target coverage during the treatment period, but the change was not significant in the Soft plan. There were significant differences in D 98% , D 95% , and D 2% in PTV between the Soft and Adaptive plans ( p < 0.05) except for D mean . There was no significant change in D max and D mean as the treatment progressed with all plans. All indices for the Adaptive plan stayed the same compared to those of iIMRT during the treatment course. There were significant differences in D 15% , D 25% , D 35% , and D 50% in the bladder between the Soft and Adaptive plans. The Adaptive plan showed the worse dose sparing than the Soft plan for the bladder according to each dosimetric index. In contrast to the bladder, the Adaptive plan achieved better sparing than the Soft plan during the treatment course. The significant differences were only observed in D 15% ...

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“…Besides eliminating the invasive process of implanting fiducial markers required at standard linacs, prostate cancer patients may also benefit from PTV margin reduction due to plan adaptation at the MRL. High risk prostate cancer patients constitute an especially interesting group for MR-guided RT, as the prostate inter-fractional motion is independent from the elective lymph node regions [14] . Both types of motion may be accounted for by daily MR-guided plan adaptation.…”

Section: Introductionmentioning

confidence: 99%

Plan quality for high-risk prostate cancer treated with high field magnetic resonance imaging guided radiotherapy

Christiansen

Hansen

Dahlrot

et al. 2018

Physics and Imaging in Radiation Oncology

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Background and purpose: Daily radiotherapy plan adaptation facilitated by a high field magnetic resonance linac (MRL) may potentially reduce the treated volume due to a reduction of the setup uncertainty. However, the technology also imposes limitations to the treatment technique compared to a standard linac. This study investigated the clinical quality of MRL treatment plans against current standard plans using identical planning target volume margins for high-risk prostate cancer patients. Materials and methods: Twenty consecutive patients planned with our current clinical standard TPS and treated with single arc VMAT on standard linacs with 78 Gy in the prostate and 56 Gy for pelvic lymph nodes over 39 fractions were included. In addition, IMRT treatment plans for delivery by a 1.5 T MRL, using standard margins and dose objectives, were made in a dedicated TPS. Mean population dose volume histograms (DVH) and dose metrics were analyzed and clinical plan quality was evaluated by an oncologist. Results: All MRL plans were considered clinically acceptable, and DVH analysis showed an overall high similarity to dose distributions of the clinically delivered plans. Mean target coverage was similar (78.0 Gy vs 77.8 Gy). Small but statistically significant differences were seen in doses to organs at risk; on average MRL plans reduced dose to the bladder (46.2 vs 48.3 Gy) compared to standard plans, while dose was higher to the bowel (29.2 vs 26.6 Gy) and penile bulb (16.5 vs 10.8 Gy). Conclusion: MRL treatment plans were clinically acceptable and similar in quality to the current standard.

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An IGRT margin concept for pelvic lymph nodes in high-risk prostate cancer

Cited by 9 publications

References 23 publications

Liquid Biopsy in Oligometastatic Prostate Cancer—A Biologist's Point of View

Liquid Biopsy in Oligometastatic Prostate Cancer—A Biologist's Point of View

Retrospective study comparing MR-guided radiation therapy (MRgRT) setup strategies for prostate treatment: repositioning vs. replanning

Plan quality for high-risk prostate cancer treated with high field magnetic resonance imaging guided radiotherapy

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