Incidence and Prognostic Factors of Painful Vertebral Compression Fracture Caused by Spine Stereotactic Body Radiotherapy

PURPOSE/OBJECTIVE(S)

Most studies of vertebral compression fracture (VCF) caused by stereotactic body radiotherapy (SBRT) do not mention the symptoms. We aimed herein to determine the rate and prognostic factors of painful VCF caused by SBRT for spinal metastasis.

MATERIALS/METHODS

Between August 2013 and December 2021, spinal segments with VCF were retrospectively identified in patients treated with spine SBRT. Iatrogenic VCFs, excluding pathological fractures, were classified into a modified group and graded using CTCAE v5.0 as grade 1 (painless), grade 2 (mildly painful), or grade 3 (intensely painful, requiring hospitalization or surgery). The primary endpoint was the rate of painful VCF (grades 2-3). Moreover, various factors specific to the patient, tumor, and treatment were evaluated to determine their value in predicting the rate of painful VCF.

RESULTS

In total, 934 spinal segments in 387 patients were analyzed. The median follow-up after SBRT was 14 (range: 0-107) months. Sixty iatrogenic fractures (6.4%) comprising 31 de novo fractures and 29 existing VCF progressions were identified. The patients' median age was 68 (range: 38-79) years, and 31 (52%) spinal segments had a history of radiotherapy. Grade 1, 2, and 3 VCFs were confirmed in 41, four, and 15 segments, respectively. The rate of grade 3 VCF was 2.0% (19 / 934) of the spinal segments treated with SBRT. Eight (0.9%) VCFs required surgery for stabilization or decompression of spinal canal stenosis. None of the 17 VCFs treated with posterior decompression and fixation before SBRT developed into a painful VCF. On univariate analysis, the painful VCF rate was significantly higher in patients with no posterolateral tumor involvement than in those with bilateral or unilateral involvement (56.3% vs 22.7%; p = 0.026). Other spinal instability neoplastic score (SINS) components (Location, Pain, Bone lesion, Alignment, Vertebral body collapse), SINS (Stable/ Potentially unstable vs Unstable), age, number of spinal levels, radiation history, existing VCF, and interval between SBRT and VCF showed no significant correlation with painful VCF.

CONCLUSION

Although VCF is a known adverse effect of spine SBRT, 68% of the cases examined were painless (grade 1). Intensely painful VCFs (grade 3) were confirmed in only 1.6% of all the treated spinal segments. The absence of posterolateral tumor involvement was significantly associated with painful VCF.

Dosimetric Evaluation of Targets and Organs at Risk in Dose Escalation Study for Total Marrow and Lymphoid Irradiation

PURPOSE/OBJECTIVE(S)

Total marrow and lymphoid irradiation (TMLI) delivers radiation dose to the bone marrow and lymph nodal region while reducing the dose to non-target organs. We conducted a dose-escalation study of TMLI to improve treatment outcomes while reducing OAR doses using intensity-modulated radiation therapy. However, this dose escalation strategy may cause increasing risk of recurrence and adverse events because of dose uniformity compromises of the target. We hypothesized that the homogeneity index (HI) could become worse with increased target's dose while maintaining reduced OAR doses for the nine patients enrolled in the TMLI phase Ⅰ clinical trial.

MATERIALS/METHODS

Nine patients treated with TMLI using a treatment delivery system from September 2019 to August 2021 were included. The prescribed doses were 14 Gy/6 fr, 16 Gy/6 fr, and 18 Gy/6 fr twice daily for 3 days, with three patients allocated each prescription. Bone marrow, lymph nodal region, spleen, testis, brain, and liver were designated as targets. The bone marrow was divided into eight parts (see Table); an individual PTV margin was added to each structure. We intended to deliver the D80% prescription dose for PTV. For the brain and liver, the prescribed dose was 12 Gy in consideration of function preservation. Lenses, oral cavity, parotid glands, lungs, heart, esophagus, stomach, kidneys, intestines, and breasts were defined as OAR. Targets were evaluated with HI that was calculated using the formula HI = (D2%-D98%)/D50%, based on ICRU report 83. For OARs, Dmax, D2%, D10%, and mean dose constraint were evaluated.

RESULTS

The table lists HI for the PTV_ALL and each target. The HI of PTV_ALL rose with increasing prescription dose and was highest at 18 Gy. The highest HI was 0.632 for PTV_Rib at 18 Gy, and the lowest HI was 0.045 for PTV_testis at 14 Gy. OAR Dose constraints were achieved in all patients. The average OAR doses in all cases for lenses, oral cavity, parotid glands, lungs, heart, esophagus, intestines, kidneys, and breast were 4.7±0.80, 4.4±0.51, 6.7±0.48, 7.6±0.22, 7.8±0.19, 6.7±0.18, 7.4±1.12, 6.9±0.96, and 14.7 Gy, respectively. The Dmax of the lenes, D2% of the esophagus, and D10% of the stomach were 7.2 ± 1.09, 11.5 ± 0.47, and 10.9 ± 0.98 Gy, respectively.

CONCLUSION

In the TMLI phase I clinical trial, we evaluated the dose uniformity to the targets and the OAR dose constraints. Although the HI for PTV_ALL worsened with increasing prescription dose, compliance with OAR dose constraints was achieved in all patients.

Multi-Institutional Fact-Finding Study: Association between Geriatric Assessment and Reduction in Intensity of Radiotherapy for Elderly Cancer Patients without Metastasis

PURPOSE/OBJECTIVE(S)

Vulnerable patients receive a low-intensity, palliative treatment rather than the standard treatment. Defining vulnerability in terms of standard or reduced radiation intensity can result in appropriate radiotherapy for elderly cancer patients without excessive adverse events and poor outcomes. However, it is difficult to define vulnerability, because radiation oncologists hesitate to include vulnerable patients in clinical trials involving radical radiotherapy. We hypothesized that for elderly cancer patients without metastasis, vulnerability scores, obtained by geriatric assessment (GA), could help in predicting the reduction in radiation intensity determined by radiation oncologists based on their experience.

MATERIALS/METHODS

In this multicenter prospective study, we enrolled cancer patients (70 years or older) without metastasis. The reduction in radiation intensity was categorized into 3 groups as follows: i) standard schedule of radiotherapy, but conversion of irradiation fields, ii) standard irradiation fields, but converted schedule of radiotherapy, and iii) conversion of radiotherapy schedule and irradiation fields. Standard radiotherapy was defined as recommended doses and radiation fields according to the guidelines for the primary tumors analyzed. GA was performed by calculating geriatric 8 (G8) and vulnerable elders survey (VES-13) scores before radiotherapy and 3-5 and 8-16 weeks after completion of radiotherapy. The primary endpoint was to evaluate the correlation between vulnerability assessed by G8 and change in radiation intensity.

RESULTS

Between November 2020 and February 2022, 317 patients were included in this study at 13 centers in Japan. The median age was 77 (range, 70-90) years. The primary cancer sites were head and neck, esophagus, lungs, breasts, pancreas, bladder, uterus, and prostate in 63, 22, 62, 48, 6, 5, 26, and 85 patients, respectively. High-precision radiotherapy was performed for 199 patients (63%). Of the 31 patients (10%) whose radiation intensity was reduced, 14, 9, and 8 patients were provided i, ii, and iii category, respectively. Planned radiotherapy was completed for 312 patients (98%). G8 and VES-13 vulnerability scores were obtained for 201 and 61 patients, respectively, before radiotherapy. The mean G8 and VES-13 scores were 13.3 ± 2.4 and 1.8 ± 1.8, 12.9 ± 2.6 and 2.0 ± 2.0, and 13.4 ± 2.4 and 2.0 ± 1.9 before radiotherapy and 3-5 and 8-16 weeks after completion of radiotherapy, respectively. Multivariate analysis revealed that reduction in radiation intensity was significantly associated with vulnerability assessed using VES-13 (p < 0.001) but not G8 (p = 0.06).

CONCLUSION

An excellent completion rate was obtained for planned radiotherapy, and vulnerability assessed using VES-13, not G8, was associated with the reduction in intensity of radiotherapy.

Long-Term Results of a Multi-Institutional Study of Dynamic Tumor Tracking-Stereotactic Body Radiotherapy for Lung Tumors

PURPOSE/OBJECTIVE(S)

We had conducted a multi-institutional phase II study to evaluate the safety and efficacy of dynamic tumor tracking-stereotactic body radiotherapy (DTT-SBRT) for lung tumors. The primary endpoint was 2-year local control, which was reported to be 95.2%. After the initial evaluation of the primary endpoint, the study was extended as an observational study which was designed to evaluate 5-year survival and late toxicities. We present the long-term results of DTT-SBRT for lung tumors.

MATERIALS/METHODS

The main eligibility criteria for the study were as follows: (1) primary or metastatic lung cancer with a diameter of 5 cm or less, and up to 3 lesions without any extrapulmonary lesions; (2) ineligibility to standard surgery, or patient's refusal of surgery; (3) ECOG-PS of 0 to 2; and (4) expected range of respiratory motion of 10 mm or more. The study included 48 patients from four institutions with the median age of 80 years (range, 49-90 years). Forty-two patients had primary non-small-cell lung cancer, and 6 patients had metastatic lung tumors. Forty-eight tumors (median diameter, 23.5 mm; range, 5-47 mm) in 48 patients were targeted for DTT-SBRT using a gimbal-mounted linear accelerator. Prior to treatment planning, spherical gold markers were placed around the tumor to detect internal tumor motion using fluoroscopy. The prescribed dose was 50 Gy in four fractions. Treatment beams were delivered with DTT according to a 4D model that predicts internal tumor motion with abdominal wall motion. DTT-SBRT was successfully delivered to all but one patient who had poor correlation between abdominal wall and tumor motion.

RESULTS

Median follow-up period at data cutoff was 5.0 years (interquartile range, 3.1-6.3 years). Twenty-nine patients died; the causes of death were cancer-specific in 10 patients, comorbidity in 14 patients (pulmonary disease, renal failure, cerebral infarction, other malignancies, etc.), and unknown in 5 patients without cancer recurrence. Overall survival at 5 years was 51.5% (95% confidence interval [CI], 36.5-64.6%). Progression-free survival and local control at 5 years were 41.0% (95% CI, 27.0-54.5%) and 92.6% (95% CI, 78.7-97.6%), respectively. There were no grade 4-5 toxicities. One patient (2%) developed grade 3 radiation pneumonitis at 3 months. Grade 2 toxicities were observed in 9 patients (19%), including dyspnea, radiation pneumonitis, pleural effusion, rib fracture, and dermatitis.

CONCLUSION

Dynamic tumor tracking SBRT achieved the long-term efficacy with low incidence of severe toxicities in lung tumors with respiratory motion. In this elderly patient cohort, non-cancer deaths were observed more than cancer-specific deaths.

Prospective Dosimetric Comparison Study Between Volumetric Modulated Arc Therapy and Intracavitary Brachytherapy for Cervical Cancer

PURPOSE/OBJECTIVE(S)

Although volumetric modulated arc therapy (VMAT) boost can achieve highly conformal dose distributions for cervical cancer, VMAT has the disadvantage of requiring set-up and organ motion margins. This study prospectively recruited patients with the cervical cancer and compared VMAT plan with intracavitary brachytherapy (ICBT) plan.

MATERIALS/METHODS

All patients treated with ICBT for locally advanced cervical cancer between April 2020 and September 2022 were enrolled. Patients had whole-pelvis radiotherapy, followed by CT scans with and without the tandem and ovoid in the same session (for the planning of ICBT and VMAT, respectively). ICBT planning characterizes the high-risk clinical target volume (HR-CTV) as the target volume and the bladder, rectum, sigmoid colon and small bowel loop as the organ at risk (OAR). VMAT planning defines the HR-CTV + 3 mm as the target volume and bladder, rectum + 3 mm (planning organ at risk volume (PRV) rectum), sigmoid colon + 3 mm (PRV sigmoid) and bowel bag as the OAR to account for set-up and organ motion. ICBT and VMAT plans were optimized for maximal dose received by at least 90% (D90%) of the target volume without impairing the dose constraints for the OARs. The prescribed dose (PD) was 26 Gy in 4 fractions. The dose constraints were determined as 25.2 Gy for D2 ml in the bladder and 20 Gy for D2 ml in the other OARs. The D90% and D100% of the target volume and D2 ml of OARs were compared between 2 plans using paired two-tailed Student's t test.

RESULTS

Seventeen patients were enrolled. Dose and volume parameters for the 2 plans are shown in Table 1. Of the 17 patients, D90% of the target volume received 100% PD in 4 cases with ICBT plans, in 6 cases for VMAT plans, and in 2 cases with both methods. For D90% of the target volume, ICBT plans were greater than VMAT plans in 4 cases, with a maximum difference of 5.6 Gy (ICBT: 26.0 Gy, SBRT: 20.4 Gy). VMAT plans were higher than ICBT plans in 11 cases, with a maximum difference of 10.3 Gy (ICBT: 14.5 Gy, SBRT: 24.8 Gy). The dose-limiting OARs to attain D90% of target volume were bladder in 12 cases and small bowel loop in 1 case for ICBT plans, while PRV rectum in 11 cases, PRV sigmoid in 4 cases and bowel bag in 1 case for VMAT plans.

CONCLUSION

This prospective study with 17 ICBT-eligible patients revealed D90% of the target volume demonstrated no substantial difference between VMAT and ICBT plans, while D100% showed a significant increase in VMAT plan compared to ICBT plan. Even with a set-up and organ motion margins on the HR-CTV and OARs, VMAT may have a dosimetric advantage over ICBT if the target geometry is complicated and close to the OARs.

A case report of hydrocephalus due to diffuse villous hyperplasia of the choroid plexus: surgical treatment by combination a flexible videoscope with a rigid endoscope

PURPOSE

Diffuse villous hyperplasia of the choroid plexus (DVHCP) and choroid plexus papilloma (CPP) are rare benign tumors usually diagnosed as a result of progressive hydrocephalus, especially in childhood. We present the case of a Japanese boy diagnosed with progressive hydrocephalus due to DVHCP.

METHODS

Case: A 2-year and 3-month-old Japanese boy was found to have delayed motor development (equivalent to 1 year and 2 months old), an enlarged head circumference of 51 cm within + 1.5 standard deviation (S.D.), and incomplete closure of the anterior fontanel. The magnetic resonance imaging (MRI) showed lobular enlargement of the bilateral choroid plexuses extending from the trigone to the body and inferior horn of the lateral ventricle. The endoscopic choroid plexus coagulation surgery was performed to reduce the CSF formation rate.

RESULTS

DVHCP was diagnosed both pathologically and clinically. Postoperatively, the patient progressed without complications, such as cerebrospinal fluid leakage. Although ventricular enlargement persisted, the anterior fontanel recessed, and the expansion of the head circumference stopped.

CONCLUSION

Few cases of bilateral DVHCP and CPP have been reported in the literature. We encountered a case in which effective choroid plexus coagulation was performed for hydrocephalus due to DVHCP using less invasive endoscopic technique. It also represented an association between DVHCP and the gain of chromosome 9p.

Cerebrospinal fluid rhinorrhea with meningoencephalocele related to Sternberg's canal: A report of two cases

Background

Cerebrospinal fluid (CSF) rhinorrhea with meningoencephalocele (MEC) associated with Sternberg's canal is rare. We treated two such cases.

Case Description

A 41-year-old man and a 35-year-old woman presented with CSF rhinorrhea and mild headache worsening with standing posture. Head computed tomography showed a defect close to the foramen rotundum in the lateral wall of the left sphenoid sinus in both cases. Head magnetic resonance (MR) imaging and MR cisternography revealed that brain parenchyma had herniated into the lateral sphenoid sinus through the defect of the middle cranial fossa. The intradural and extradural spaces and bone defect were sealed with fascia and fat through both intradural and extradural approaches. The MEC was cut away to prevent infection. CSF rhinorrhea completely stopped after the surgery.

Conclusion

Our cases were characterized by empty sella, thinning of the dorsum sellae, and large arteriovenous malformations that suggest chronic intracranial hypertension. The possibility of Sternberg's canal in patients with CSF rhinorrhea with chronic intracranial hypertension should be considered. The cranial approach has the advantages of lower infection risk and the ability to close the defect with multilayer plasty under direct vision. The transcranial approach is still safe if performed by a skillful neurosurgeon.

[Dysgenesis of CNS in dyscranio-pygo-phalangia (author's transl)]

A rare case of dyscranio-pygo-phalangia was studied neuropathologically. The patient was a 19 days old boy, who showed multiple anomalies: protuberance of forehead, narrow eye fissures, microphthalmos, micrognathia, microauriculae with dysplasia, hexadactylia of extremities, cryptorchism, asymmetric thorax, congenital heart disease and hypoplasia of the right lung. There were multiple dysgeneses in the central nervous system, especially the cerebellum: floccular heterotopia; heterotopias of cortex type, cerebellar nucleic type and Purkinje cell type; external granular layer cells in the white matter; dentate spindle-cell-dysgenesis. Other findings were glio-neurono-mesenchymal dysgenesis on the surface of the brain, residual fetal external granular layer on the surface of the pons, partial hypoplasia of corpus callosum, heterotopic nerve cells in the molecular layer of the periinsular cortex.

[Congenital muscular dystrophy associated with micropolygyria of the cerebrum and cerebellum]

The characteristic features of micropolygyria were demonstrated in the cerebral and cerebellar gray matter of two cases, 5 and 16 years old males, of congenital muscular dystrophy. (Fokuyama type). The micropolygyria of the cerebral cortex showed an undifferentiated cytoarchitecture, e. g. status verrucosus deformis. On the surface of cortical molecular layer, subpial mesenchymal fibres, tangential myelin fibres and marginal glial fibres were observed to be still proliferated even at the stages examined and all the fibres were caved into the cortical cell layer associated with the molecular layer, without secondary sulcus formation. It is proposed that micropolygyria without secondary sulcus formation described in the present paper is named as "pachygyric micropolygyria", while four-layered type of micropolygyria with normal sulcus formation is "eugyric micropolygyria". On the other hand, micropolygyria of the cerebellar cortex was found to be consisted of various sized fragments in which basic structures of the cerebellum were preserved. On a part of surface of the cerebellar cortex the cytoarchitecture of cell layers was shown in inverse order. The Purkinje cell were irregularly migrated and the external granular layer remained in the molecular layer showing ectopic features. Tangential myelin fibres, connecting with fibres of the folial white matter, were observed to exist on the surface of the internal granular layer.