Post-Operative Stereotactic Radiotherapy for Resected Brain Metastases: Results of the Multicenter Analysis (AURORA) of the German Working Group "Stereotactic Radiotherapy"

PURPOSE/OBJECTIVE(S)

While the results of prospective studies support the use of postoperative stereotactic radiotherapy (RT) to the resection cavity (RC) as the standard of care after surgery, there are several issues that need to be investigated such as factors for improving local control, risk of leptomeningeal disease and radiation necrosis. Further, the optimal dose and fractionation is still under debate.

MATERIALS/METHODS

The working group "Stereotactic Radiotherapy" of the German Society of Radiation Oncology (DEGRO) analyzed its multi-institutional database with 661 patients who received postoperative stereotactic RT to the RC. Treatment was performed at 13 centers between 2008 and 2021. Patient characteristics, treatment details, and follow-up data including overall survival (OS), local control (LC) were evaluated. Cox Regression and Kaplan-Meier curves with Log-rank Tests were calculated for selected variables.

RESULTS

In this retrospective study, overall survival was 61.5% at 1 year, 47.6% at 2 years, and 35.5% at 3 years, and local control was 84.6% at 1 year, 74.8% at 2 years, and 72.8% at 3 years. 96% of patients were treated with hypofractionated stereotactic radiotherapy (HSRT), only 26 patients received single fraction radiosurgery (4%). Prognostic factors associated with overall survival were Karnofsky Performance Status, RPA and GPA class, controlled primary tumor and absence of extracranial metastases, whereas prognostic factor associated with local control was planning target volume (23 mL or less).

CONCLUSION

HSRT is the most common fractionation form in the treatment of RCs in this multicenter analysis. This approach results in excellent OS and LC outcomes. OS in patients with resected brain metastases is mainly influenced by performance status. In regard to local control, RT of large cavities remain a challenge with significantly worse outcome.

Dosimetric Comparison Between Helical Tomotherapy and Volumetric Modulated Arc Therapy in Patients With Malignant Pleural Mesothelioma

AIMS

To carry out a dosimetric comparison and constraints feasibility proof of adjuvant radiotherapy through helical tomotherapy or volumetric modulated arc therapy (VMAT) for malignant pleural mesothelioma patients after pleurectomy/decortication.

MATERIALS AND METHODS

Retrospective calculations were carried out on previously acquired simulations. A whole-pleura volume with 50.4 Gy in 28 fractions was prescribed, simulating a no residual tumour situation. Calculations were carried out using an anisotropic analytical algorithm with a 2.0 mm grid. Beam-on time, planning target volume (PTV) coverage, homogeneity index and organ at risk exposure were compared.

RESULTS

Sixteen patient plans were calculated per device. Constraints were met overall by both modalities. For helical tomotherapy and VMAT plans, median beam-on times were 13.8 (11.6-16.1) min and 6.4 (6.1-7.0) min; P = 0.006. The median left-sided radiotherapy PTV D₉₈ were 48.1 (48.0-48.8) Gy and 47.6 (46.5-48.3) Gy; P = 0.023. No significant difference for right-sided radiotherapy was found. PTV D₂ for left-sided radiotherapy was higher with VMAT (P = 0.014). For right-sided radiotherapy, helical tomotherapy showed higher doses (P = 0.039). No homogeneity index differences for left-sided radiotherapy (P = 1.00) and right-sided radiotherapy (P = 0.598) were seen. Significant organ at risk exposure differences were found on left-sided radiotherapy whole-lung V_20, as well as D₅₀ (both P = 0.008). Higher contralateral lung and ipsilateral kidney exposures were found with VMAT plans for both treatment sides.

CONCLUSION

Adjuvant radiotherapy after pleurectomy/decortication in malignant pleural mesothelioma patients, with a VMAT- or helical tomotherapy-based platform, is dosimetrically feasible. Lung sparing was mostly improved with helical tomotherapy. Technique selection must be carried out according to availability and clinical criteria.

Improving interinstitutional and intertechnology consistency of pulmonary SBRT by dose prescription to the mean internal target volume dose

Purpose

Dose, fractionation, normalization and the dose profile inside the target volume vary substantially in pulmonary stereotactic body radiotherapy (SBRT) between different institutions and SBRT technologies. Published planning studies have shown large variations of the mean dose in planning target volume (PTV) and gross tumor volume (GTV) or internal target volume (ITV) when dose prescription is performed to the PTV covering isodose. This planning study investigated whether dose prescription to the mean dose of the ITV improves consistency in pulmonary SBRT dose distributions.

Materials and methods

This was a multi-institutional planning study by the German Society of Radiation Oncology (DEGRO) working group Radiosurgery and Stereotactic Radiotherapy. CT images and structures of ITV, PTV and all relevant organs at risk (OAR) for two patients with early stage non-small cell lung cancer (NSCLC) were distributed to all participating institutions. Each institute created a treatment plan with the technique commonly used in the institute for lung SBRT. The specified dose fractionation was 3 × 21.5 Gy normalized to the mean ITV dose. Additional dose objectives for target volumes and OAR were provided.

Results

In all, 52 plans from 25 institutions were included in this analysis: 8 robotic radiosurgery (RRS), 34 intensity-modulated (MOD), and 10 3D-conformal (3D) radiation therapy plans. The distribution of the mean dose in the PTV did not differ significantly between the two patients (median 56.9 Gy vs 56.6 Gy). There was only a small difference between the techniques, with RRS having the lowest mean PTV dose with a median of 55.9 Gy followed by MOD plans with 56.7 Gy and 3D plans with 57.4 Gy having the highest. For the different organs at risk no significant difference between the techniques could be found.

Conclusions

This planning study pointed out that multiparameter dose prescription including normalization on the mean ITV dose in combination with detailed objectives for the PTV and ITV achieve consistent dose distributions for peripheral lung tumors in combination with an ITV concept between different delivery techniques and across institutions.

Supplementary Information

The online version of this article (10.1007/s00066-021-01799-w) contains supplementary material, which is available to authorized users.

Prognostic impact of gross tumor volume during radical radiochemotherapy of locally advanced non-small cell lung cancer-results from the NCT03055715 multicenter cohort study of the Young DEGRO Trial Group

BACKGROUND

In radical radiochemotherapy (RCT) of inoperable non-small-cell lung cancer (NSCLC) typical prognostic factors include T- and N-stage, while there are still conflicting data on the prognostic relevance of gross tumor volume (GTV) and particularly its changes during RCT. The NCT03055715 study of the Young DEGRO working group of the German Society of Radiation Oncology (DEGRO) evaluated the prognostic impact of GTV and its changes during RCT.

METHODS

A total of 21 university centers for radiation oncology from five different European countries (Germany, Switzerland, Spain, Belgium, and Austria) participated in the study which evaluated n = 347 patients with confirmed (biopsy) inoperable NSCLC in UICC stage III A/B who received radical curative-intent RCT between 2010 and 2013. Patient and disease data were collected anonymously via electronic case report forms and entered into the multi-institutional RadPlanBio platform for central data analysis. GTV before RCT (initial planning CT, GTV1) and at 40-50 Gy (re-planning CT for radiation boost, GTV2) was delineated. Absolute GTV before/during RCT and relative GTV changes were correlated with overall survival as the primary endpoint. Hazard ratios (HR) of survival analysis were estimated by means of adjusted Cox regression models.

RESULTS

GTV1 was found to have a mean of 154.4 ml (95%CI: 1.5-877) and GTV2 of 106.2 ml (95% CI: 0.5-589.5), resulting in an estimated reduction of 48.2 ml (p < 0.001). Median overall survival (OS) was 18.8 months with a median of 22.1, 20.9, and 12.6 months for patients with high, intermediate, and low GTV before RT. Considering all patients, in one survival model of overall mortality, GTV2 (2.75 (1.12-6.75, p = 0.03) was found to be a stronger survival predictor than GTV1 (1.34 (0.9-2, p > 0.05). In patients with available data on both GTV1 and GTV2, absolute GTV1 before RT was not significantly associated with survival (HR 0-69, 0.32-1.49, p > 0.05) but GTV2 significantly predicted OS in a model adjusted for age, T stage, and chemotherapy, with an HR of 3.7 (1.01-13.53, p = 0.04) per 300 ml. The absolute decrease from GTV1 to GTV2 was correlated to survival, where every decrease by 50 ml reduced the HR by 0.8 (CI 0.64-0.99, p = 0.04). There was no evidence for a survival effect of the relative change between GTV1 and GTV2.

CONCLUSION

Our results indicate that independently of T stage, the re-planning GTV during RCT is a significant and superior survival predictor compared to baseline GTV before RT. Patients with a high absolute (rather than relative) change in GTV during RT show a superior survival outcome after RCT.

Influence of localization of PSMA-positive oligo-metastases on efficacy of metastasis-directed external-beam radiotherapy-a multicenter retrospective study

PURPOSE

Approximately 40-70% of biochemically persistent or recurrent prostate cancer (PCa) patients after radical prostatectomy (RPE) are oligo-metastatic in ⁶⁸gallium-prostate-specific membrane antigen positron emission tomography (⁶⁸Ga-PSMA PET). Those lesions are frequently located outside the prostate bed, and therefore not cured by the current standards of care like external-beam radiotherapy (EBRT) of the prostatic fossa. This retrospective study analyzes the influence of oligo-metastases' site on outcome after metastasis-directed radiotherapy (MDR).

METHODS

Retrospectively, 359 patients with PET-positive PCa recurrences after RPE were analyzed. Biochemical recurrence-free survival (BRFS) (prostate-specific antigen (PSA) < post-radiotherapy nadir + 0.2 ng/mL) was assessed using Kaplan-Meier survival and Cox regression analysis.

RESULTS

All patients were initially clinically without distant metastases (cM0). Seventy-five patients had local recurrence within the prostatic fossa, 32 patients had pelvic nodal plus local recurrence, 117 patients had pelvic nodal recurrence, 51 patients had paraaortic lymph node metastases with/without locoregional recurrence, and 84 patients had bone or visceral metastases with/without locoregional recurrence. Median PSA before MDR was 1.2 ng/mL (range, 0.04-47.5). Additive androgen deprivation therapy (ADT) was given in 35% (125/359) of patients. Median PSA nadir after MDR was 0.23 ng/mL (range, < 0.03-18.30). After a median follow-up of 16 months (1-57), 239/351 (68%) patients had no biochemical recurrence. Patients with distant lymph node and/or distant metastases, the so-called oligo-body cohort, had an overall in-field control of 90/98 (91%) but at the same time, an ex-field progress of 44/96 (46%). In comparison, an ex-field progress was detected in 28/154 (18%) patients with local and/or pelvic nodal recurrence (oligo-pelvis group). Compared with the oligo-pelvis group, there was a significantly lower BRFS in oligo-body patients at the last follow-up.

CONCLUSION

Overall, BRFS was dependent on patterns of metastatic disease. Thus, MDR of PSMA PET-positive oligo-metastases can be offered considering that about one-third of the patients progressed within a median follow-up of 16 months.

The impact of local control on overall survival after stereotactic body radiotherapy for liver and lung metastases from colorectal cancer: a combined analysis of 388 patients with 500 metastases

BACKGROUND

The aim of this analysis was to model the effect of local control (LC) on overall survival (OS) in patients treated with stereotactic body radiotherapy (SBRT) for liver or lung metastases from colorectal cancer.

METHODS

The analysis is based on pooled data from two retrospective SBRT databases for pulmonary and hepatic metastases from 27 centers from Germany and Switzerland. Only patients with metastases from colorectal cancer were considered to avoid histology as a confounding factor. An illness-death model was employed to model the relationship between LC and OS.

RESULTS

Three hundred eighty-eight patients with 500 metastatic lesions (lung n = 209, liver n = 291) were included and analyzed. Median follow-up time for local recurrence assessment was 12.1 months. Ninety-nine patients with 112 lesions experienced local failure. Seventy-one of these patients died after local failure. Median survival time was 27.9 months in all patients and 25.4 months versus 30.6 months in patients with and without local failure after SBRT. The baseline risk of death after local failure exceeds the baseline risk of death without local failure at 10 months indicating better survival with LC.

CONCLUSION

In CRC patients with lung or liver metastases, our findings suggest improved long-term OS by achieving metastatic disease control using SBRT in patients with a projected OS estimate of > 12 months.

[Plastic reconstruction of radiation injuries]

In addition to surgical and drug therapy, radiotherapy (or radiation therapy) is one of the three mainstays of modern oncological therapy regimes. It uses ionizing radiation to control tumors by damaging the DNA of cancerous tissue leading to cellular death. Although advances have been made in recent years resulting in a reduced dosage to the surrounding tissues, radiation injuries and tissue-related side effects cannot be completely avoided. Knowledge of the pathophysiology, treatment modalities and interdisciplinary treatment approaches are essential for effective therapy whilst limiting side effects. Surgery within the irradiated area is technically demanding due to tissue alterations and unpredictable wound healing. The plastic reconstructive surgeon either faces the challenge of delayed wound healing following neoadjuvant radiation or chronic radiation-linked changes following previous radiotherapy, which can also occur after a latency period of many years. Reconstructive interventions can be essential to repair deficits of a functional and/or aesthetic nature in order to maintain a high quality of life for oncology patients. This can also be of benefit to patients in a palliative oncological setting to improve daily functions and quality of life.

Nomogram based overall survival prediction in stereotactic body radiotherapy for oligo-metastatic lung disease

BACKGROUND

Radical local treatment of pulmonary metastases is practiced with increasing frequency due to acknowledgment and better understanding of oligo-metastatic disease. This study aimed to develop a nomogram predicting overall survival (OS) after stereotactic body radiotherapy (SBRT) for pulmonary metastases.

PATIENTS AND METHODS

A multi-institutional database of 670 patients treated with SBRT for pulmonary metastases was used as training cohort. Cox regression analysis with bidirectional variable elimination was performed to identify factors to be included into the nomogram model to predict 2-year OS. The calibration rate of the nomogram was assessed by plotting the actual Kaplan-Meier 2-year OS against the nomogram predicted survival. The nomogram was externally validated using two separate monocentric databases of 145 and 92 patients treated with SBRT for pulmonary metastases.

RESULTS

The median follow up of the trainings cohort was 14.3months, the 2-year and 5-year OS was 52.6% and 23.7%, respectively. Karnofsky performance index, type of the primary tumor, control of the primary tumor, maximum diameter of the largest treated metastasis and number of metastases (1 versus >1) were significant prognostic factors in the Cox model (all p<0.05). The calculated concordance-index for the nomogram was 0.73 (concordance indexes of all prognostic factors between 0.54 and 0.6). Based on the nomogram the training cohort was divided into 4 groups and 2-year OS ranged between 24.2% and 76.1% (predicted OS between 30.2% and 78.4%). The nomogram discriminated between risk groups in the two validation cohorts (concordance index 0.68 and 0.67).

CONCLUSIONS

A nomogram for prediction of OS after SBRT for pulmonary metastases was generated and externally validated. This tool might be helpful for interdisciplinary discussion and evaluation of local and systemic treatment options in the oligo-metastatic setting.

KEY MESSAGE

A nomogram for prediction of overall survival after stereotactic body radiotherapy (SBRT) for pulmonary metastases was developed and externally validated. This tool might be helpful for interdisciplinary discussion and evaluation of local and systemic treatment options in the oligo-metastatic setting.

A new era of thoracic oncology? Ex-vivo stereotactic ablative radiosurgery within Ex-vivo Lung Treatment System as a hybrid therapy for unresectable locally advanced pulmonary malignancies

The concept of oligometastases is the medical rationale for a local treatment of a limited number of metastatic tumor manifestations. Patients with pulmonary oligometastases are candidates for surgery or radiotherapy, however there are a number of technical issues that limit treatment. Technical issues relating to radiotherapy include organs at risk of irradiation, chest wall toxicity and decreased precision of tumor targeting because of breathing movements. Technical issues relating to surgery include loss of lung parenchyma and unresectability. We propose the hypothesis that ex-vivo radiosurgery as new hybrid technique in thoracic oncology has the capability to overcome these technical issues and will expand the medical spectrum in thoracic oncology. The proposed - highly complex - technique consists of surgical lung explantation, followed by stereotactic radiotherapy during ex-vivo perfusion followed by surgical re-implantation.

Inhalative steroids as an individual treatment in symptomatic lung cancer patients with radiation pneumonitis grade II after radiotherapy - a single-centre experience

Purpose

To assess efficacy of our single-centre experience with inhalative steroids (IS) in lung cancer patients with symptomatic radiation pneumonitis (RP) grade II.

Material and methods

Between 05/09 and 07/10, 24 patients (female, n = 8; male, n = 16) with lung cancer (non-small cell lung carcinoma [NSCLC]: n = 19; small cell lung cancer [SCLC]: n = 3; unknown histology: n = 2) and good performance status (ECOG ≤1) received definitive radiotherapy to the primary tumour site and involved lymph nodes with concurrent chemotherapy (n = 18), sequential chemotherapy (n = 2) or radiation only (n = 4) and developed symptomatic RP grade II during follow-up. No patient presented with oxygen requiring RP grade III. The mean age at diagnosis was 66 years (range: 50–82 years). Nine patients suffered from chronic obstructive pulmonary disease (COPD) before treatment, and 18 patients had a smoking history (median pack years: 48). The mean lung dose was 15.5 Gy (range: 3.0–23.1 Gy). All patients were treated with IS. If a patient’s clinical symptoms did not significantly improve within two weeks of IS therapy initiation, their treatment was switched to oral prednisolone.

Results

All 24 patients were initially treated with a high dose IS (budesonide 800 μg 1-0-1) for 14 days. Of the patients, 18 showed a significant improvement of clinical symptoms and 6 patients did not show significant improvement of clinical symptoms and were classified as non-responders to IS. Their treatment was switched to oral steroids after two weeks (starting with oral prednisolone, 0.5 mg/kg bodyweight; at least 50 mg per day). All of these patients responded to the prednisolone. None of non-responders presented with increased symptoms of RP and required oxygen and / or hospitalization (RP grade III). The median follow-up after IS treatment initiation was 18 months (range: 4–66 months). The median duration of IS treatment and prednisolone treatment was 8.2 months (range: 3.0–48.3 months) and 11.4 months (range: 5.0–44.0 months), respectively. Of the 18 IS treatment responders, 2 (11.1 %) patients with pre-existing grade 2 COPD still required IS (400 μg twice a day) 45.0 and 48.3 months after radiotherapy, respectively. For the remaining 16 responders (88.9 %), IS therapy was stopped after 7.7 months (range: 3.0–18.2 months). None of the patients treated with IS developed any specific IS-related side effects such as oral candidiasis.

Conclusion

This single-centre experience shows that high-dose IS is an individual treatment option for radiation-induced pneumonitis grade II in patients with a good performance status.