Stereotactic ultrahypofractionated MR-guided radiotherapy for localized prostate cancer - Acute toxicity and patient-reported outcomes in the prospective, multicenter SMILE phase II trial

Background

Due to superior image quality and daily adaptive planning, MR-guided stereotactic body radiation therapy (MRgSBRT) has the potential to further widen the therapeutic window in radiotherapy of localized prostate cancer. This study reports on acute toxicity rates and patient-reported outcomes after MR-guided adaptive ultrahypofractionated radiotherapy for localized prostate cancer within the prospective, multicenter phase II SMILE trial.

Materials and methods

A total of 69 patients with localized prostate cancer underwent MRgSBRT with daily online plan adaptation. Inclusion criteria comprised a tumor stage ≤ T3a, serum PSA value ≤ 20 ng/ml, ISUP Grade group ≤ 4. A dose of 37.5 Gy was prescribed to the PTV in five fractions on alternating days with an optional simultaneous boost of 40 Gy to the dominant intraprostatic lesion defined by multiparametric MRI. Acute genitourinary (GU-) and gastrointestinal (GI-) toxicity, as defined by CTCAE v. 5.0 and RTOG as well as patient-reported outcomes according to EORTC QLQ-C30 and -PR25 scores were analyzed at completion of radiotherapy, 6 and 12 weeks after radiotherapy and compared to baseline symptoms.

Results

There were no toxicity-related treatment discontinuations. At the 12-week follow-up visit, no grade 3 + toxicities were reported according to CTCAE. Up until the 12-week visit, in total 16 patients (23 %) experienced a grade 2 GU or GI toxicity. Toxicity rates peaked at the end of radiation therapy and subsided within the 12-week follow-up period. At the 12-week follow-up visit, no residual grade 2 GU toxicities were reported and 1 patient (1 %) had residual grade 2 enteritic symptoms. With exception to a significant improvement in the emotional functioning score following MRgSBRT, no clinically meaningful changes in the global health status nor in relevant subscores were reported.

Conclusion

Daily online-adaptive MRgSBRT for localized prostate cancer resulted in an excellent overall toxicity profile without any major negative impact on quality of life.

ESTRO clinical practice guideline: Stereotactic body radiotherapy for spine metastases

BACKGROUND AND PURPOSE

Recent progress in diagnostics and treatment of metastatic cancer patients have improved survival substantially. These developments also affect local therapies, with treatment aims shifting from short-term palliation to long-term symptom or disease control. There is consequently a need to better define the value of stereotactic body radiotherapy (SBRT) for the treatment of spinal metastases.

METHODS

This ESTRO clinical practice guideline is based on a systematic literature review conducted according to PRISMA standards, which formed the basis for answering four key questions about the indication and practice of SBRT for spine metastases.

RESULTS

The analysis of the key questions based on current evidence yielded 22 recommendations and 5 statements with varying levels of endorsement, all achieving a consensus among experts of at least 75%. In the majority, the level of evidence supporting the recommendations and statements was moderate or expert opinion, only, indicating that spine SBRT is still an evolving field of clinical research. Recommendations were established concerning the selection of appropriate patients with painful spine metastases and oligometastatic disease. Recommendations about the practice of spinal SBRT covered technical planning aspects including dose and fractionation, patient positioning, immobilization and image-guided SBRT delivery. Finally, recommendations were developed regarding quality assurance protocols, including description of potential SBRT-related toxicity and risk mitigation strategies.

CONCLUSIONS

This ESTRO clinical practice guideline provides evidence-based recommendations and statements regarding the selection of patients with spinal metastases for SBRT and its safe implementation and practice. Enrollment of patients into well-designed prospective clinical trials addressing clinically relevant questions is considered important.

Efficacy and safety of SBRT for spine metastases: A systematic review and meta-analysis for preparation of an ESTRO practice guideline

BACKGROUND AND PURPOSE

Advances in characterizing cancer biology and the growing availability of novel targeted agents and immune therapeutics have significantly changed the prognosis of many patients with metastatic disease. Palliative radiotherapy needs to adapt to these developments. In this study, we summarize the available evidence for stereotactic body radiotherapy (SBRT) in the treatment of spinal metastases.

MATERIALS AND METHODS

A systematic review and meta-analysis was performed using PRISMA methodology, including publications from January 2005 to September 2021, with the exception of the randomized phase III trial RTOG-0631 which was added in April 2023. Re-irradiation was excluded. For meta-analysis, a random-effects model was used to pool the data. Heterogeneity was assessed with the I2-test, assuming substantial and considerable as I2 > 50 % and I2 > 75 %, respectively. A p-value < 0.05 was considered statistically significant.

RESULTS

A total of 69 studies assessing the outcomes of 7236 metastases in 5736 patients were analyzed. SBRT for spine metastases showed high efficacy, with a pooled overall pain response rate of 83 % (95 % confidence interval [CI] 68 %-94 %), pooled complete pain response of 36 % (95 % CI: 20 %-53 %), and 1-year local control rate of 94 % (95 % CI: 86 %-99 %), although with high levels of heterogeneity among studies (I2 = 93 %, I2 = 86 %, and 86 %, respectively). Furthermore, SBRT was safe, with a pooled vertebral fracture rate of 9 % (95 % CI: 4 %-16 %), pooled radiation induced myelopathy rate of 0 % (95 % CI 0-2 %), and pooled pain flare rate of 6 % (95 % CI: 3 %-17 %), although with mixed levels of heterogeneity among the studies (I2 = 92 %, I2 = 0 %, and 95 %, respectively). Only 1.7 % of vertebral fractures required surgical stabilization.

CONCLUSION

Spine SBRT is characterized by a favorable efficacy and safety profile, providing durable results for pain control and disease control, which is particularly relevant for oligometastatic patients.

Advances in rectal cancer: Real-world evidence suggests limited gains in prognosis for elderly patients

BACKGROUND

Rectal cancer treatment has improved considerably due to the introduction of total meso-rectal excision, radio-chemotherapy, and high-resolution imaging. The aim of this observational cohort study was to quantify the effectiveness of these advances using high-quality data from a representative cohort of patients.

METHODS

20 281 non-metastasized cases retrieved from the Munich Cancer Registry database were divided into three time periods corresponding to before (1988-1997), partial (1998-2007), and full implementation (2008-2019) of clinical advances. Early-onset (<50 yrs.), middle-aged, elderly patient subgroups (> 70 yrs.) were compared. The overall effectiveness of evidence-based guideline adherence was also examined.

RESULTS

Median survival improved by 1.5 yrs. from the first to the last time period. Relative survival increased from 74.9% (5-yr 95%CI[73.3 - 76.6]) to 79.2% (95%CI[77.8 - 80.5]). The incidence of locoregional recurrences was reduced dramatically by more than half (5-yr 17.7% (95%CI[16.5 - 18.8]); 6.7% (95%CI[6.1 - 7.3])). Gains in 5-yr relative survival were limited to early-onset and middle-aged patients with no significant improvement seen in elderly patients (Female 68.6% [63.9 - 73.3] to 67.6% [64.0 - 71.2]; Male 71.7% [65.9 - 77.4] to 74.0% [70.8 - 77.2]).

CONCLUSIONS

Real-world evidence suggests that recent treatment advances have lead to an increase in prognosis for rectal cancer patients. However, more effort should be made to improve the implementation of new developments in elderly patients. Especially considering, that these cases represent a growing majority of diagnosed patients.

P03.03.A STEREOBRAIN: Stereotactic radiosurgery versus whole-brain radiotherapy in patients with 4-10 brain metastases - a non-randomized controlled trial

Background

Since the JLGK0901 study described non-inferiority of stereotactic radiosurgery (SRS) of 5-10 compared to 2-4 brain metastases in 2014, it has been widely discussed if SRS should replace whole brain radiotherapy (WBRT) in 5 - 10 brain metastases though lacking randomized evidence. At our department, WBRT has been the treatment of choice in 4-10 brain metastases until 2017. This paradigm was entirely changed to include patients within the STEREOBRAIN trial (DRKS00014694). We designed this prospective controlled single arm trial to systematically introduce SRS to 4 to 10 brain metastases comparing this new treatment regimen with the former approach. We aimed at showing a survival benefit of this novel treatment paradigm.

Material and Methods

Inclusion criteria were 4-10 brain metastases, largest diameter 2.5 cm, all histologies except SCLC, germ cell tumors, lymphoma, and ECOG ≤ 2. The retrospective WBRT cohort was identically selected from consecutive patients from 2012 to 2017 in a 1:2 fashion. At a significance level of 5%, a total number of 99 events (deaths) across the two groups allows to detect an increase in median OS from 6 months (retrospective WBRT cohort) to 11 months (SRS) considered clinically relevant (and corresponding to a hazard ratio of 0.55 assuming exponential distributions of survival times within groups) with a power of 80%. Propensity-score matching was performed to take confounders into account given the inherent bias caused by different treatment periods. Multiple brain mets SRS was performed using a single-isocenter technique.

Results

Patients were recruited from 2017 - 2020 and end of F/U was July 1st 2021. Forty patients were recruited to the SRS cohort and 70 patients were eligible within the WBRT cohort (81 events altogether). Median follow-up, OS and intracranial progression free survival were 21.6 months (95%-CI 19.8-NA), 10.4 months (95%-CI 9.3-NA) and 7.1 months (95%-CI 3.9-14.2) for the SRS-cohort, and 61.4 months (95% 54.6-NA), 6.5 months (95%-CI 4.9-10.4) and 5.9 months (95%-CI 4.1-8.8) for the WBRT-cohort, respectively. The Cox-model yielded a trend for improved survival within the SRS-cohort, HR 0.65 (95%-CI 0.4-1.1); p=0.076. After optimal propensity score matching, OS was significantly superior for the SRS-cohort (HR 0.53 (95%-CI 0.32-0.86), p=0.01). No grade III toxicities were observed in the SRS-cohort.

Conclusion

Despite all limitations of a historical control and missing the target number of events, there was a clear signal of improved survival with SRS compared to WBRT for patients with 4-10 metastases. Whether adapted WBRT (hippocampal sparing, simultaneous integrated boost) or SRS is to be preferred needs to be investigated in the future.

Stereotactic MRI-guided radiation therapy for localized prostate cancer (SMILE): a prospective, multicentric phase-II-trial

Background

Normofractionated radiation regimes for definitive prostate cancer treatment usually extend over 7–8 weeks. Recently, moderate hypofractionation with doses per fraction between 2.2 and 4 Gy has been shown to be safe and feasible with oncologic non-inferiority compared to normofractionation. Radiobiologic considerations lead to the assumption that prostate cancer might benefit in particular from hypofractionation in terms of tumor control and toxicity. First data related to ultrahypofractionation demonstrate that the overall treatment time can be reduced to 5–7 fractions with single doses > 6 Gy safely, even with simultaneous focal boosting of macroscopic tumor(s). With MR-guided linear accelerators (MR-linacs) entering clinical routine, invasive fiducial implantations become unnecessary. The aim of the multicentric SMILE study is to evaluate the use of MRI-guided stereotactic radiotherapy for localized prostate cancer in 5 fractions regarding safety and feasibility.

Methods

The study is designed as a prospective, one-armed, two-stage, multi-center phase-II-trial with 68 patients planned. Low- and intermediate-risk localized prostate cancer patients will be eligible for the study as well as early high-risk patients (cT3a and/or Gleason Score ≤ 8 and/or PSA ≤ 20 ng/ml) according to d’Amico. All patients will receive definitive MRI-guided stereotactic radiation therapy with a total dose of 37.5 Gy in 5 fractions (single dose 7.5 Gy) on alternating days. A focal simultaneous integrated boost to MRI-defined tumor(s) up to 40 Gy can optionally be applied. The primary composite endpoint includes the assessment of urogenital or gastrointestinal toxicity ≥ grade 2 or treatment-related discontinuation of therapy. The use of MRI-guided radiotherapy enables online plan adaptation and intrafractional gating to ensure optimal target volume coverage and protection of organs at risk.

Discussion

With moderate hypofractionation being the standard in definitive radiation therapy for localized prostate cancer at many institutions, ultrahypofractionation could be the next step towards reducing treatment time without compromising oncologic outcomes and toxicities. MRI-guided radiotherapy could qualify as an advantageous tool as no invasive procedures have to precede in therapeutic workflows. Furthermore, MRI guidance combined with gating and plan adaptation might be essential in order to increase treatment effectivity and reduce toxicity at the same time.

MRI-based contrast clearance analysis shows high differentiation accuracy between radiation-induced reactions and progressive disease after cranial radiotherapy

Background

Pseudoprogression (PsP) or radiation necrosis (RN) may frequently occur after cranial radiotherapy and show a similar imaging pattern compared with progressive disease (PD). We aimed to evaluate the diagnostic accuracy of magnetic resonance imaging-based contrast clearance analysis (CCA) in this clinical setting.

Patients and methods

Patients with equivocal imaging findings after cranial radiotherapy were consecutively included into this monocentric prospective study. CCA was carried out by software-based automated subtraction of imaging features in late versus early T1-weighted sequences after contrast agent application. Two experienced neuroradiologists evaluated CCA with respect to PsP/RN and PD being blinded for histological findings. The radiological assessment was compared with the histopathological results, and its accuracy was calculated statistically.

Results

A total of 33 patients were included; 16 (48.5%) were treated because of a primary brain tumor (BT), and 17 (51.1%) because of a secondary BT. In one patient, CCA was technically infeasible. The accuracy of CCA in predicting the histological result was 0.84 [95% confidence interval (CI) 0.67-0.95; one-sided P = 0.051; n = 32]. Sensitivity and specificity of CCA were 0.93 (95% CI 0.66-1.00) and 0.78 (95% CI 0.52-0.94), respectively. The accuracy in patients with secondary BTs was 0.94 (95% CI 0.71-1.00) and nonsignificantly higher compared with patients with primary BT with an accuracy of 0.73 (95% CI 0.45-0.92), P = 0.16.

Conclusions

In this study, CCA was a highly accurate, easy, and helpful method for distinguishing PsP or RN from PD after cranial radiotherapy, especially in patients with secondary tumors after radiosurgical treatment.

•

CCA is accurate in distinguishing treatment reactions from true PD.

•

CCA was more accurate for irradiated metastases than primary BTs.

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CCA is not feasible for lesions with no contrast media uptake.

Longitudinal changes of blood parameters and weight in inoperable stage III NSCLC patients treated with concurrent chemoradiotherapy followed by maintenance treatment with durvalumab

Background

Investigating dynamic changes in blood-parameters and weight in patients with locally advanced non-small cell lung cancer (NSCLC) receiving durvalumab maintenance therapy after chemoradiotherapy (cCRT). Laboratory outcomes were determined based on the number of durvalumab administrations received.

Methods

Twenty-two patients completed platinum-based cCRT followed by maintenance treatment with durvalumab. Different parameters such as hemoglobin (Hb), leukocytes, Lactate dehydrogenase (LDH), C-reactive protein (CRP), body weight and albumin were analyzed before cCRT, after cCRT, 3, 6, 9 and 12 months after starting durvalumab maintenance.

Results

Sixteen (72.7%) patients were male; twelve (54.5%) and fifteen (68.2%) patients had non-squamous histology and Union for International Cancer Control (UICC) stage IIIB-C disease, respectively. Median follow-up time was 24.4 months; 12- and 18-months- progression-free and overall-survival rates were 55.0% and 45.0 as well as 90.2 and 85.0%, respectively.

During maintenance treatment Hb increased by 1.93 mg/dl (17.53%) after 9 months (p < 0.001) and 2.02 mg/dl (18.46%) after 12 months compared to the start of durvalumab (p < 0.001). LDH decreased by 29.86 U/l (− 11.74%) after 3 months (p = 0.022). Receipt of at least 12 cycles of durvalumab was beneficial in terms of Hb-recovery (Hb 6 months: 12.64 vs. 10.86 [mg/dl]; Hb 9 months: 13.33 vs 11.74 [mg/dl]; (p = 0.03)). Median weight change [kilogram (kg)] was + 6.06% (range: − 8.89 − + 18.75%) after 12 months. The number of durvalumab cycles significantly correlated with total weight gain [kg] (Spearman-Rho-correlation: r = 0.502*).

Conclusion

In the investigated cohort, no severe hematologic toxicity occurred by laboratory blood tests within 1 year of durvalumab maintenance therapy after cCRT for unresectable stage III NSCLC. Receiving at least 12 cycles of durvalumab appears to have a significant effect on recovery of hemoglobin levels and body weight.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09395-6.

MR-guided adaptive stereotactic body radiotherapy (SBRT) of primary tumor for pain control in metastatic pancreatic ductal adenocarcinoma (mPDAC): an open randomized, multicentric, parallel group clinical trial (MASPAC)

Background

Pain symptoms in the upper abdomen and back are prevalent in 80% of patients with metastatic pancreatic ductal adenocarcinoma (mPDAC), where the current standard treatment is a systemic therapy consisting of at least doublet-chemotherapy for fit patients. Palliative low-dose radiotherapy is a well-established local treatment option but there is some evidence for a better and longer pain response after a dose-intensified radiotherapy of the primary pancreatic cancer (pPCa). Stereotactic body radiation therapy (SBRT) can deliver high radiation doses in few fractions, therefore reducing chemotherapy-free intervals. However, prospective data on pain control after SBRT of pPCa is very limited. Therefore, we aim to investigate the impact of SBRT on pain control in patients with mPDAC in a prospective trial.

Methods

This is a prospective, double-arm, randomized controlled, international multicenter study testing the added benefit of MR-guided adaptive SBRT of the pPca embedded between standard of care-chemotherapy (SoC-CT) cycles for pain control and prevention of pain in patients with mPDAC. 92 patients with histologically proven mPDAC and at least stable disease after initial 8 weeks of SoC-CT will be eligible for the trial and 1:1 randomized in 3 centers in Germany and Switzerland to either experimental arm A, receiving MR-guided SBRT of the pPCa with 5 × 6.6 Gy at 80% isodose with continuation of SoC-CT thereafter, or control arm B, continuing SoC-CT without SBRT. Daily MR-guided plan adaptation intents to achieve good target coverage, while simultaneously minimizing dose to organs at risk. Patients will be followed up for minimum 6 and maximum of 18 months. The primary endpoint of the study is the “mean cumulative pain index” rated every 4 weeks until death or end of study using numeric rating scale.

Discussion

An adequate long-term control of pain symptoms in patients with mPDAC is an unmet clinical need. Despite improvements in systemic treatment, local complications due to pPCa remain a clinical challenge. We hypothesize that patients with mPDAC will benefit from a local treatment of the pPCa by MR-guided SBRT in terms of a durable pain control with a simultaneously favorable safe toxicity profile translating into an improvement of quality-of-life.

Trial registration

German Registry for Clinical Trials (DRKS): DRKS00025801. Meanwhile the study is also registered at ClinicalTrials.gov with the Identifier: NCT05114213.

Pan-Asian adaptation of the EHNS-ESMO-ESTRO Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with squamous cell carcinoma of the head and neck

The most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of squamous cell carcinoma (SCC) of the oral cavity, larynx, oropharynx and hypopharynx was published in 2020. It was therefore decided by both the ESMO and the Korean Society of Medical Oncology (KSMO) to convene a special, virtual guidelines meeting in July 2021 to adapt the ESMO 2020 guidelines to consider the potential ethnic differences associated with the treatment of SCCs of the head and neck (SCCHN) in Asian patients. These guidelines represent the consensus opinions reached by experts in the treatment of patients with SCCHN (excluding nasopharyngeal carcinomas) representing the oncological societies of Korea (KSMO), China (CSCO), India (ISMPO), Japan (JSMO), Malaysia (MOS), Singapore (SSO) and Taiwan (TOS). The voting was based on scientific evidence and was independent of the current treatment practices and drug access restrictions in the different Asian countries. The latter was discussed when appropriate. This manuscript provides a series of expert recommendations (Clinical Practice Guidelines) which can be used to provide guidance to health care providers and clinicians for the optimisation of the diagnosis, treatment and management of patients with SCC of the oral cavity, larynx, oropharynx and hypopharynx across Asia.

Effectiveness and tolerability of radiotherapy for patients with indolent non-Hodgkin's lymphoma: a monocenter analysis

To analyze the effectiveness and toxicities of radiotherapy in indolent non-Hodgkin's lymphoma (iNHL) patients treated in our institution. Patients with iNHL treated with radiotherapy between 1999 and 2016 were included. The primary endpoint was progression-free survival (PFS). Secondary endpoints were local control (LC), overall survival (OS) and toxicities. PFS, LC, and OS were analyzed using Kaplan-Meier method. Log-rank test was used to investigate the differences between subgroups. Cox proportional hazard model was used for univariate continuous analysis. Seventy-five patients were identified in our institutional database between 1999 and 2016. Fifty-eight (77.3%) had stage I after Ann-Arbor and 17 patients (22.7%) had stage II. The median follow-up was 87 months (95% CI 72-102 months). Median single dose per fraction was 2.0 Gy (range 1.5-2 Gy) and median total dose was 30.6 Gy (range 16-45 Gy). Radiotherapy was performed in 2D (n = 10; 13.3%), 3D (n = 63; 84.0%) and VMAT (n = 2; 2.7%) techniques, respectively. The median PFS was 14.0 years (95% CI 8.3-19.7 years). The estimated PFS after 5 and 10 years were 73.0% and 65.5% in Kaplan-Meier analysis, respectively. The 5- and 10-year LC were 94.9% and 92.3%, respectively. The 5- and 10-year OS were 88.6% and 73.9%. In univariate analyses of PFS, younger patients (≤ 60 years old) had significantly superior PFS to those older than 60 years old (5-year PFS 81.9% vs. 65.1%, p = 0.021). Dose escalation > 36.0 Gy had no prognostic influence in term of PFS (p = 0.425). Extranodal involvement, stage and histology had no prognostic impact on PFS. Depending on the site of lymphomas, the most common acute side effects were: dermatitis CTCAE° I-II (8.0%), xerostomia CTC° I (8.0%), cataract CTC° I (12.0%) and dry eyes CTC° I-II (14.6%). No adverse event CTC° III was reported. Most acute side effects recovered at 3 to 6 months after radiotherapy except for CTC° I cataract and xerostomia. Local Radiotherapy was highly effective for treatment of early stage iNHL with no serious side effects in our cohort. The most acute CTCAE° I-II side effects recovered 3 to 6 months later. Technique advances seem to have further improved effectiveness and tolerability of radiotherapy.Trial registration: Local ethics committee of Ludwig-Maximilian-University (LMU) Munich approved this retrospective analysis on the May 7th, 2019 (Nr. 19-137).

Integration of radiation oncology teaching in medical studies by German medical faculties due to the new licensing regulations : An overview and recommendations of the consortium academic radiation oncology of the German Society for Radiation Oncology (DEGRO)

The new Medical Licensing Regulations 2025 (Ärztliche Approbationsordnung, ÄApprO) will soon be passed by the Federal Council (Bundesrat) and will be implemented step by step by the individual faculties in the coming months. The further development of medical studies essentially involves an orientation from fact-based to competence-based learning and focuses on practical, longitudinal and interdisciplinary training. Radiation oncology and radiation therapy are important components of therapeutic oncology and are of great importance for public health, both clinically and epidemiologically, and therefore should be given appropriate attention in medical education. This report is based on a recent survey on the current state of radiation therapy teaching at university hospitals in Germany as well as the contents of the National Competence Based Learning Objectives Catalogue for Medicine 2.0 (Nationaler Kompetenzbasierter Lernzielkatalog Medizin 2.0, NKLM) and the closely related Subject Catalogue (Gegenstandskatalog, GK) of the Institute for Medical and Pharmaceutical Examination Questions (Institut für Medizinische und Pharmazeutische Prüfungsfragen, IMPP). The current recommendations of the German Society for Radiation Oncology (Deutsche Gesellschaft für Radioonkologie, DEGRO) regarding topics, scope and rationale for the establishment of radiation oncology teaching at the respective faculties are also included.

P05.01 Prospective validation trial of magnetic resonance imaging based Contrast Clearance Analysis (CCA) to differentiate between pseudoprogression/radiation necrosis and progressive disease following cranial radiotherapy

BACKGROUND

Pseudoprogression (PsP) or radiation necrosis (RN) may frequently occur after cranial radiotherapy and show a similar imaging pattern compared to progressive disease (PD). Even for experienced neuroradiologists, it remains challenging to distinguish between these clinically relevant disease states. We aimed to evaluate the diagnostic accuracy of magnetic resonance imaging (MRI) based Contrast Clearance Analysis (CCA) in this clinical setting.

MATERIAL AND METHODS

Patients with equivocal imaging findings after cranial radiotherapy were consecutively included into this monocentric prospective study. Assuming a true accuracy of 90% and setting the significance level to 0.05, N=33 patients are required to show that accuracy is larger than 70% with a power of 80% using a one-sided binomial test. CCA was performed by subtraction of imaging features in late vs early T1-weighted sequences after contrast-agent application. Two experienced neuroradiologists evaluated CCA with respect to PsP/RN and PD being blinded for FET PET and histological findings; histopathological diagnosis was based on stereotactic biopsy or resection for space-occupying processes. The radiological assessment was compared with the histopathological results, and its accuracy was calculated statistically.

RESULTS

Thirty-three patients were included; sixteen (48.5%) were treated because of a primary brain tumors, and 17 (51.1%) with brain metastases. In one patient, CCA was technically infeasible. The accuracy of CCA in predicting the histological result was 0.84 (95% CI 0.67–0.95; one-sided p=0.05; N=32). An accuracy of 0.85 (95% CI 0.68–0.95; one-sided p=0.04) would have been obtained in case of a correct classification in the non-analyzable case. Sensitivity and specificity of CCA were 0.93 (95%-CI 0.66–1.00) and 0.78 (95% CI 0.52–0.94), respectively. The accuracy in metastases patients was 0.94 (95% CI 0.71 - 1.00) and non-significantly higher compared to primary brain tumor patients with accuracy of 0.73 (95% CI 0.45 - 0.92), p=0.16.

CONCLUSION

In this study, CCA was a highly accurate, easy and helpful method for distinguishing PsP or RN from PD after cranial radiotherapy, especially in brain metastases patients after radiosurgical treatment.