Radiotherapy concepts for spinal metastases-results from an online survey among radiation oncologists of the German Society for Radiation Oncology

PURPOSE

Spinal metastases (SM) are a common radiotherapy (RT) indication. There is limited level I data to drive decision making regarding dose regimen (DR) and target volume definition (TVD). We aim to depict the patterns of care for RT of SM among German Society for Radiation Oncology (DEGRO) members.

METHODS

An online survey on conventional RT and Stereotactic Body Radiation Therapy (SBRT) for SM, distributed via e‑mail to all DEGRO members, was completed by 80 radiation oncologists between February 24 and April 29, 2022. Participation was voluntary and anonymous.

RESULTS

A variety of DR was frequently used for conventional RT (primary: n = 15, adjuvant: n = 14). 30 Gy/10 fractions was reported most frequently. TVD in adjuvant RT was heterogenous, with a trend towards larger volumes. SBRT was offered in 65% (primary) and 21% (adjuvant) of participants' institutions. A variety of DR was reported (primary: n = 40, adjuvant: n = 27), most commonly 27 Gy/3 fractions and 30 Gy/5 fractions. 59% followed International Consensus Guidelines (ICG) for TVD.

CONCLUSION

We provide a representative depiction of RT practice for SM among DEGRO members. DR and TVD are heterogeneous. SBRT is not comprehensively practiced, especially in the adjuvant setting. Further research is needed to provide a solid data basis for detailed recommendations.

SBRT of Spinal Metastases Using a Simultaneous Integrated Boost Concept in Oligometastatic Cancer Patients Is Safe and Effective

(1) Purpose: To assess the safety and effectivity of stereotactic body radiotherapy (SBRT) on spinal metastases utilizing a simultaneous integrated boost (SIB) concept in oligometastatic cancer patients. (2) Methods: 62 consecutive patients with 71 spinal metastases received SIB-SBRT between 01/2013 and 09/2022 at our institution. We retrospectively analyzed toxicity, local tumor control (LC), and progression-free (PFS) and overall survival (OS) following SIB-SBRT and assessed possible influencing factors (Kaplan-Meier estimator, log-rank test and Cox proportional-hazards model). (3) Results: SIB-SBRT was delivered in five fractions, mostly with 25/40 Gy (n = 43; 60.56%) and 25/35 Gy (n = 19, 26.76%). Estimated rates of freedom from VCF were 96.1/90.4% at one/two years. VCF development was significantly associated with osteoporosis (p < 0.001). No ≥ grade III acute and one grade III late toxicity (VCF) were observed. Estimated LC rates at one/two years were 98.6/96.4%, and histology was significantly associated with local treatment failure (p = 0.039). Median PFS/OS was 10 months (95% CI 6.01-13.99)/not reached. Development of metastases ≥ one year after initial diagnosis and Karnofsky Performance Score ≥ 90% were predictors for superior PFS (p = 0.038) and OS (p = 0.012), respectively. (4) Conclusion: Spinal SIB-SBRT yields low toxicity and excellent LC. It may be utilized in selected oligometastatic patients to improve prognosis. To the best of our knowledge, we provide the first clinical data on the toxicity and effectivity of SIB-SBRT in spinal metastases in a larger patient cohort.

Current situation in radiation oncology residency-Results of a national survey performed by the working group Young DEGRO of the German Society of Radiation Oncology

BACKGROUND

The aim of this study was to assess the current status of the radiation oncology (RO) residency programs in Germany. For this, RO residents and RO specialists were surveyed regarding the current situation of the RO residency training and the working conditions in Germany.

METHODS

The Continuing Education Section of the Young DEGRO (yDEGRO) Working Group of the German Society of Radiation Oncology (DEGRO) developed a survey to assess (1) the overall satisfaction, learning objectives, and teaching methods used during training; and (2) the perception of the importance of specific disease patterns in RO training. Open-ended questions were also asked to elicit opinions on areas for improvement. From 21 November to 27 December 2022, RO residents registered with DEGRO and/or in the working group yDEGRO were invited to participate anonymously in an online questionnaire.

RESULTS

Overall, 97 participants completed the survey, including 65 RO residents (67%) and 32 RO specialists (33%); 66 (68%) of the respondents reported being employed in the university setting, 23 (23.7%) in the non-university setting, and 8 (8.3%) in private practice. Within the training, heterogeneity was found in the teaching methods used. In terms of knowledge transfer, the greatest importance was accorded to annual continuing education discussions with the head of the residency training (92.8%), participation in tumor boards (85.6%), written training concepts (81.4%), and evaluations at the beginning (76.3%) and end of a rotation (80.4%). The arithmetic mean of satisfaction with specialist training was 6/10 points (SD: 1.99); 88.7% of respondents would like to see a nationally uniform and mandatory curriculum in RO residency training.

CONCLUSION

The study provides suggestions for improving RO medical training in Germany: further development of accompanying education and training programs in cooperation with professional associations, e.g., the DEGRO, structured feedback, and supervision.

Hypofractionated Stereotactic Radiotherapy vs. Single Fraction Stereotactic Radiosurgery to the Resection Cavity of Brain Metastases after Surgical Resection (SATURNUS trial): A Prospective, Randomized Phase III Trial

PURPOSE/OBJECTIVE(S)

The brain is a common site for metastases. Resection of large or symptomatic metastases is followed by stereotactic radiotherapy to prevent local recurrence. The optimal fractionation scheme is subject of ongoing research. Supported by emerging retrospective data, we hypothesize that hypofractionated stereotactic radiotherapy (HFSRT) is superior to single-fraction stereotactic radiosurgery (SRS) in terms of local control (LC). We designed the SATURNUS trial to prospectively demonstrate the superiority of HFSRT over SRS after resection of brain metastases in terms of LC.

MATERIALS/METHODS

The SATURNUS trial is a prospective, randomized phase III trial, currently recruiting patients at a single institution. Patients are 1:1 allocated to HFSRT or SRS using permuted block randomization. Affiliation to the treatment arm is solely blinded to the neuroradiologist assessing therapy response. HFSRT will be delivered with 6 - 7 x 5 Gy and SRS with 1 x 12-20 Gy, prescribed to the surrounding isodose, depending on cavity size and proximity to structures at risk. For SRS, doses do not exceed the maximum doses according to RTOG 90-05. Case number calculation was based on own institutional data on HFSRT (mean LC rate of 88% at 12 months) and data from large phase III trials on SRS (pooled mean LC rate of 66% at 12 months). Using a Chi-squared test of equal proportions (odds ratio = 1), setting test significance level (α) to 0.05, and allocating an equal number of patients to both treatment arms, 114 patients are needed to detect the superiority of HFSRT in terms of LC at 12 months (primary endpoint) with a power of at least 80%. Estimating a dropout rate of 10%, the case number was set to 126. The trial was registered with clinicaltrials.gov (NCT05160818). The first patient was enrolled in May 2021 and recruitment is ongoing. Patients with up to three resected brain metastases are considered for study participation. Further eligibility criteria are histologically confirmed solid tumor disease, resection cavity diameter ≤ 4 cm, consent to perform adjuvant radiotherapy by an interdisciplinary tumor board, completed wound healing, resection within the last six weeks at the time of study inclusion, age ≥ 18 years, KPS ≥ 60%, adequate contraceptive measures for fertile women / men and written informed consent. Patients are followed up clinically and with MRI at 6 weeks and 3, 6, 9 and 12 months after treatment. LC is assessed according to RANO-BM. Toxicity (CTCAE v4.03) is assessed as a secondary endpoint. The rather broad dose corridors allowed within the trial do justice to clinical reality, however, may represent a limitation of the trial. They are therefore addressed with a predefined subgroup analysis, as will be cavity size, among others. Participation of further study centers is desired. To the best of our knowledge, the SATURNUS trial is the only randomized phase III trial adequately powered to detect the superiority of HFSRT over SRS with regard to LC for resected brain metastases.

RESULTS

To be determined.

CONCLUSION

To be determined.

Hypofractionated stereotactic radiotherapy (HFSRT) versus single fraction stereotactic radiosurgery (SRS) to the resection cavity of brain metastases after surgical resection (SATURNUS): study protocol for a randomized phase III trial

BACKGROUND

The brain is a common site for cancer metastases. In case of large and/or symptomatic brain metastases, neurosurgical resection is performed. Adjuvant radiotherapy is a standard procedure to minimize the risk of local recurrence and is increasingly performed as local stereotactic radiotherapy to the resection cavity. Both hypofractionated stereotactic radiotherapy (HFSRT) and single fraction stereotactic radiosurgery (SRS) can be applied in this case. Although adjuvant stereotactic radiotherapy to the resection cavity is widely used in clinical routine and recommended in international guidelines, the optimal fractionation scheme still remains unclear. The SATURNUS trial prospectively compares adjuvant HFSRT with SRS and seeks to detect the superiority of HFSRT over SRS in terms of local tumor control.

METHODS

In this single center two-armed randomized phase III trial, adjuvant radiotherapy to the resection cavity of brain metastases with HFSRT (6 - 7 × 5 Gy prescribed to the surrounding isodose) is compared to SRS (1 × 12-20 Gy prescribed to the surrounding isodose). Patients are randomized 1:1 into the two different treatment arms. The primary endpoint of the trial is local control at the resected site at 12 months. The trial is based on the hypothesis that HFSRT is superior to SRS in terms of local tumor control.

DISCUSSION

Although adjuvant stereotactic radiotherapy after resection of brain metastases is considered standard of care treatment, there is a need for further prospective research to determine the optimal fractionation scheme. To the best of our knowledge, the SATURNUS study is the only randomized phase III study comparing different regimes of postoperative stereotactic radiotherapy to the resection cavity adequately powered to detect the superiority of HFSRT regarding local control.

TRIAL REGISTRATION

The study was retrospectively registered with ClinicalTrials.gov, number NCT05160818, on December 16, 2021. The trial registry record is available on  https://clinicaltrials.gov/study/NCT05160818 . The presented protocol refers to version V1.3 from March 21, 2021.

Dose-escalated re-irradiation improves outcome in locally recurrent head and neck cancer - Results of a large multicenter analysis

To determine efficacy and prognostic parameters of definitive re-irradiation of locoregionally recurrent squamous cell carcinoma of the head and neck (HNSCC).

MATERIALS AND METHODS

Patients with locoregionally recurrent or second primary HNSCC undergoing re-irradiation with modern radiotherapy technique were eligible for this multicentric retrospective analysis. Main endpoints were overall survival (OS), progression-free survival (PFS) and locoregional control (LC). Univariate analyses were performed using the Kaplan Meier Method (log-rank). For multivariable analysis, Cox regression was used.

RESULTS

A total of 253 patients treated between 2009 and 2020 at 16 university hospitals in Germany were included. The median follow up was 27.4 months (range 0.5-130). The median OS and PFS were 13.2 (CI: 10.7 - 15.7) months and 7.9 (CI: 6.7 - 9.1) months, respectively, corresponding to two-year OS and PFS rates of 29 % and 19 %. Rates of locoregional progression and "in-field-failure" were 62 % and 51 % after two years. Multivariable Cox regression analysis identified good ECOG performance status and high radiation dose as independent prognostic parameters for OS. Doses above 50 Gy (EQD2) achieved longer median OS of 17.8 months (vs 11.7 months, p < 0.01) and longer PFS of 9.6 months (vs 6.8 months, p < 0.01). In addition, there was a trend for worse survival in patients with tracheostomy (multivariable, p = 0.061). Concomitant systemic therapy did not significantly impact PFS or OS.

CONCLUSION

Re-irradiation of locally recurrent or second primary HNSCC is efficient, especially if doses above 50 Gy (EQD2) are delivered. ECOG performance score was the strongest prognostic parameter for OS and PFS.

Low-Energy X-Ray Intraoperative Radiation Therapy (Lex-IORT) for Resected Brain Metastases: A Single-Institution Experience

BACKGROUND

Resection followed by local radiation therapy (RT) is the standard of care for symptomatic brain metastases. However, the optimal technique, fractionation scheme and dose are still being debated. Lately, low-energy X-ray intraoperative RT (lex-IORT) has been of increasing interest.

METHOD

Eighteen consecutive patients undergoing BM resection followed by immediate lex-IORT with 16-30 Gy applied to the spherical applicator were retrospectively analyzed. Demographic, RT-specific, radiographic and clinical data were reviewed to evaluate the effectiveness and safety of IORT for BM. Descriptive statistics and Kaplan-Meyer analysis were applied.

RESULTS

The mean follow-up time was 10.8 months (range, 0-39 months). The estimated local control (LC), distant brain control (DBC) and overall survival (OS) at 12 months post IORT were 92.9% (95%-CI 79.3-100%), 71.4% (95%-CI 50.2-92.6%) and 58.0% (95%-CI 34.1-81.9%), respectively. Two patients developed radiation necrosis (11.1%) and wound infection (CTCAE grade III); both had additional adjuvant treatment after IORT. For five patients (27.8%), the time to the start or continuation of systemic treatment was ≤15 days and hence shorter than wound healing and adjuvant RT would have required.

CONCLUSION

In accordance with previous series, this study demonstrates the effectiveness and safety of IORT in the management of brain metastases despite the small cohort and the retrospective characteristic of this analysis.

The impact of tumor metabolic activity assessed by 18F-FET amino acid PET imaging in particle radiotherapy of high-grade glioma patients

Background

Selective uptake of (18)F-fluoro-ethyl-tyrosine (¹⁸F-FET) is used in high-grade glioma (HGG) to assess tumor metabolic activity via positron emission tomography (PET). We aim to investigate its value for target volume definition, as a prognosticator, and associations with whole-blood transcriptome liquid biopsy (WBT lbx) for which we recently reported feasibility to mirror tumor characteristics and response to particle irradiation in recurrent HGG (rHGG).

Methods

¹⁸F-FET-PET data from n = 43 patients with primary glioblastoma (pGBM) and n = 33 patients with rHGG were assessed. pGBM patients were irradiated with photons and sequential proton/carbon boost, and rHGG patients were treated with carbon re-irradiation (CIR). WBT (Illumina HumanHT-12 Expression BeadChips) lbx was available for n = 9 patients from the rHGG cohort. PET isocontours (40%–70% SUVmax, 10% steps) and MRI-based treatment volumes (MRIvol) were compared using the conformity index (CI) (pGBM, n = 16; rHGG, n = 27). Associations with WBT lbx data were tested on gene expression level and inferred pathways activity scores (PROGENy) and from transcriptome estimated cell fractions (CIBERSORT, xCell).

Results

In pGBM, median SUVmax was higher in PET acquired pre-radiotherapy (4.1, range (R) 1.5–7.8; n = 20) vs. during radiotherapy (3.3, R 1.5–5.7, n = 23; p = 0.03) and in non-resected (4.7, R 2.9–7.9; n = 11) vs. resected tumors (3.3, R 1.5–7.8, n = 32; p = 0.01). In rHGG, a trend toward higher SUVmax values in grade IV tumors was observed (p = 0.13). Median MRIvol was 32.34 (R 8.75–108.77) cm³ in pGBM (n = 16) and 20.77 (R 0.63–128.44) cm³ in rHGG patients (n = 27). The highest median CI was observed for 40% (pGBM, 0.31) and 50% (rHGG, 0.43, all tumors) isodose, with 70% (40%) isodose in grade III (IV) rHGG tumors (median CI, 0.38 and 0.49). High SUVmax was linked to shorter survival in pGBM (>3.3, p = 0.001, OR 6.0 [2.1–17.4]) and rHGG (>2.8, p = 0.02, OR 4.1 [1.2–13.9]). SUVmax showed associations with inferred monocyte fractions, hypoxia, and TGFbeta pathway activity and links to immune checkpoint gene expression from WBT lbx.

Conclusion

The benefits of ¹⁸F-FET-PET imaging on gross tumor volume (GTV) definition for particle radiotherapy warrant further evaluation. SUVmax might assist in prognostic stratification of HGG patients for particle radiotherapy, highlights heterogeneity in rHGG, and is positively associated with unfavorable signatures in peripheral whole-blood transcriptomes.

Efficacy of re-irradiation with carbon ions (RiCi) in patients with recurrent high-grade glioma (rHGG) compared to the standard re-irradiation with photons (RiP): The reference multicenter cohort of the German Cancer Consortium Radiation Oncology Group (DKTK-ROG)

2057

Background: Local recurrence after surgery and radio(chemo)therapy remains a major obstacle in curative treatment of patients with HGG. Eradication of radioresistant glioma subpopulations (hypoxic- and stem cell like cells) together with formation of an antiangiogenic and immuno-permissive glioma niche are among beneficial radiobiological effects recently attributed to carbon ion irradiation in preclinical models. The impact of this novel therapy in management of rHGG patients remains elusive. Methods: 197 patients with rHGG (grade III: 71, IV: 126) received RiCi between Nov 2009 and Feb 2018 at HIT with a median dose of 42GyRBE in 14 fractions. In DKTK-ROG multicenter cohort n:565 rHGG patients (grade III: 63, IV: 479) underwent RiP between 1997-2016 with a median dose of 36 Gy in 14 fractions. Median follow up was 34.2 months (M) for RiCi and 7.1 M for RiP (DKTK) cohort. All three prognostic scores validated in DKTK-ROG cohort were evaluated and re-irradiation risk score (RRRS) considering initial grade, Karnofsky Performance Score and age at re-irradiation was utilized for stratification and matched comparisons. Results: Median PFS was 5.08 [4.26-5.87] M (grade III: 6.79, grade IV: 3.64) after RiCi, data was not available for RiP. Median OS was 10.52 [9.28-12.66] M (grade III: 28.2, grade IV: 8.53) after RiCi compared to 7.93 [7.15-8.79] M (grade III: 10.89, grade IV: 7.93) after RiP. Among the three prognostic scores evaluated, RRRS most robustly correlated with OS. RiCi was associated with HR of 0.52 ([0.49-0.72], p = 0.0000002), and HR 0.66 ([0.51-0.85], p = 0.001) for RRRS matched analysis. Conclusions: Carbon ions demonstrated activity in rHGG. This effect is most prominent in grade III while grade IV patients may further benefit from innovative multimodal strategies. Based on these encouraging results prospective randomized trials utilizing RRRS for stratification are recommended.