Semi-automated volumetric analysis of lymph node metastases in patients with malignant melanoma stage III/IV-A feasibility study

Therapy monitoring in oncological patient care requires accurate and reliable imaging and post-processing methods. RECIST criteria are the current standard, with inherent disadvantages. The aim of this study was to investigate the feasibility of semi-automated volumetric analysis of lymph node metastases in patients with malignant melanoma compared to manual volumetric analysis and RECIST. Multislice CT was performed in 47 patients, covering the chest, abdomen and pelvis. In total, 227 suspicious, enlarged lymph nodes were evaluated retrospectively by two radiologists regarding diameters (RECIST), manually measured volume by placement of ROIs and semi-automated volumetric analysis. Volume (ml), quality of segmentation (++/−−) and time effort (s) were evaluated in the study. The semi-automated volumetric analysis software tool was rated acceptable to excellent in 81% of all cases (reader 1) and 79% (reader 2). Median time for the entire segmentation process and necessary corrections was shorter with the semi-automated software than by manual segmentation. Bland-Altman plots showed a significantly lower interobserver variability for semi-automated volumetric than for RECIST measurements. The study demonstrated feasibility of volumetric analysis of lymph node metastases. The software allows a fast and robust segmentation in up to 80% of all cases. Ease of use and time needed are acceptable for application in the clinical routine. Variability and interuser bias were reduced to about one third of the values found for RECIST measurements.     

应用Ilizarov外固定器治疗儿童马蹄内翻足12例

1临床资料1997-10/2003-5采用Ilizarov外固定器结合足部小手术矫正足部畸形12例(12足),男9例,女3例,年龄3.3～9.2岁,平均5.5岁.其中先天性者8例(均为僵硬型,其他手术方法治疗后复发),神经源性3例(系脑脊膜膨出引起),外伤性者1例(烧伤引起).手术前根据患儿年龄、患足畸形程度、大小及X线片形态结构特点,选择合适的Ilizarov外固定器.     

Salvage Surgery in Patients with Local Recurrence After Radical Prostatectomy

BackgroundSince the introduction of prostate-specific membrane antigen (PSMA) positron emission tomography (PET) imaging, isolated local recurrence after radical prostatectomy (RP) can be delineated accurately.ObjectiveTo describe and evaluate surgical technique, biochemical response, and therapy-free survival (TFS) after salvage surgery in patients with local recurrence in the seminal vesicle bed.Design, setting, and participantsWe retrospectively assessed 40 patients treated with open salvage surgery in two centres (11/2014-02/2020). All patients presented with biochemical recurrence (BCR) after RP with a singular local recurrence at PSMA PET imaging. Thirty-three (82.5%) patients received previous salvage radiation therapy.Surgical procedureOpen salvage surgery with PSMA radioguidance.MeasurementsProstate-specific antigen (PSA) nadir and percentage of patients with complete biochemical response (cBR) without further treatment (PSA < 0.2 ng/ml) after 6–16 wk were assessed. BCR-free survival and TFS were calculated using Kaplan-Meier estimates. Clavien-Dindo complications were evaluated.Results and limitationsPrior to salvage surgery, median PSA was 0.9 ng/ml (interquartile range [IQR]: 0.5–1.7 ng/ml). Postoperatively, median PSA nadir was 0.1 ng/ml (IQR: 0–0.4 ng/ml). In 31 (77.5%) patients, cBR was observed. During the median follow-up of 24.4 months, 22 (55.0%) patients experienced BCR and 12 (30.0%) received further therapy. At 1 yr of follow-up, BCR-free survival rate was 62.2% and TFS rate was 88.3%. Three (7.5%) Clavien-Dindo grade III complications were observed. The main limitations are the retrospective design, short follow-up, and lack of a control group.ConclusionsSalvage surgery of local recurrence within the seminal vesicle bed is feasible. It may present an opportunity in selected, locally recurrent patients to prolong BCR-free survival and increase TFS. Further studies are needed to confirm our findings.Patient summaryWe looked at the outcomes from prostate cancer patients with locally recurrent disease after radical prostatectomy and radiotherapy. We found that surgery in well-selected patients may be an opportunity to prolong treatment-free survival.     

Targeted alpha therapy of mCRPC: Dosimetry estimate of <Superscript>213</Superscript>Bismuth-PSMA-617

Purpose

PSMA-617 is a small molecule targeting the prostate-specific membrane antigen (PSMA). In this work, we estimate the radiation dosimetry for this ligand labeled with the alpha-emitter ²¹³Bi.

Methods

Three patients with metastatic prostate cancer underwent PET scans 0.1 h, 1 h, 2 h, 3 h, 4 h and 5 h after injection of ⁶⁸Ga-PSMA-617. Source organs were kidneys, liver, spleen, salivary glands, bladder, red marrow and representative tumor lesions. The imaging nuclide ⁶⁸Ga was extrapolated to the half-life of ²¹³Bi. The residence times of ²¹³Bi were forwarded to the instable daughter nuclides. OLINDA was used for dosimetry calculation. Results are discussed in comparison to literature data for ²²⁵Ac-PSMA-617.

Results

Assuming a relative biological effectiveness of 5 for alpha radiation, the dosimetry estimate revealed equivalent doses of mean 8.1 Sv _RBE5/GBq for salivary glands, 8.1 Sv _RBE5/GBq for kidneys and 0.52 Sv _RBE5/GBq for red marrow. Liver (1.2 Sv _RBE5/GBq), spleen (1.4 Sv _RBE5/GBq), bladder (0.28 Sv _RBE5/GBq) and other organs (0.26 Sv_RBE5/GBq) were not dose-limiting. The effective dose is 0.56 Sv _RBE5/GBq. Tumor lesions were in the range 3.2–9.0 Sv_RBE5/GBq (median 7.6 Sv_RBE5/GBq). Kidneys would limit the cumulative treatment activity to 3.7 GBq; red marrow might limit the maximum single fraction to 2 GBq. Despite promising results, the therapeutic index was inferior compared to ²²⁵Ac-PSMA-617.

Conclusions

Dosimetry of ²¹³Bi-PSMA-617 is in a range traditionally considered reasonable for clinical application. Nevertheless, compared to ²²⁵Ac-PSMA-617, it suffers from higher perfusion-dependent off-target radiation and a longer biological half-life of PSMA-617 in dose-limiting organs than the physical half-life of ²¹³Bi, rendering this nuclide as a second choice radiolabel for targeted alpha therapy of prostate cancer.

     

Leiomyosarcoma of the inferior vena cava]

Leiomyosarcomas of the inferior vena cava are rare and the clinical symptoms unspecific. We report a case of leiomyosarcoma of the inferior vena cava in an 82-year-old woman presenting with weight loss and abdominal pain. Following elaborate preoperative examinations, surgical resection was performed and the inferior vena cava was reconstructed. Clinical signs, diagnosis, therapy, and prognosis are discussed.