One Year Radiographic Response Following Prostrate SBRT: An Exploratory Analysis of a Phase III Randomized Trial

PURPOSE/OBJECTIVE(S)

Radiographic MRI response following prostate radiotherapy, particularly stereotactic body radiotherapy (SBRT), remains poorly understood. Our objective was to describe radiographic changes to the prostate gland and prostate tumor following SBRT of men treated on a prospective, randomized trial.

MATERIALS/METHODS

MIRAGE (NCT04384770) is a single center, randomized phase III trial of patients receiving either CT or MRI guided SBRT for localized prostate cancer. Patients underwent pre-treatment and annual post-treatment MRIs, in addition to routine PSA surveillance. Outcomes reported include percent gland shrinkage, percent PSA response at one year, and presence of residual tumor based on radiographic interpretation. Patient characteristics were compared via two-sample t-test or Fischer's exact test. Both univariate and multivariable logistical analysis were employed to identify potential clinical predictors of residual tumor on 1-year follow up MRI.

RESULTS

This study cohort included 94 eligible patients with baseline characteristics in Table 1. Residual lesions were seen in 13 patients (14%), 5/27 (18.5%) treated without ADT and 8/67 (12%) with ADT. PSA ablation was deep, with a 79% median decrease without ADT and 98% median decrease with ADT. Patients receiving ADT showed more gland shrinkage (17% vs. 34% shrinkage, p = 0.0001), while radiographic non-responders and responders experienced similar gland shrinkage (median 21% vs 29% shrinkage, p > 0.05). No significant clinical predictors of residual tumor were identified on univariate and multivariate analysis. No patient had any clinical or biochemical evidence of failure.

CONCLUSION

A total of 14% of patients were found to have residual tumor detected on MRI one year after SBRT. These data highlight the protracted nature of radiographic tumor response to radiation therapy, even with ablative radiation techniques. The analysis is limited by the lack of biopsy data to quantify whether visualized residual tumor harbor active cancer.

Quantitative gait and postural analyses in patients with diabetic polyneuropathy

BACKGROUND

Although gait disturbances are relatively common symptoms in diabetic polyneuropathy (DPN), few studies have quantitatively analyzed gait and posture in DPN patients. This study aimed to analyze gait and posture quantitatively in DPN patients and to determine the association between clinical and electrophysiological parameters and gait and posture parameters.

METHODS

Sixty-four DPN patients were enrolled in this study. DPN was clinically assessed using the Toronto clinical neuropathy score (TCNS). All participants underwent nerve conduction study (NCS), three-dimensional motion analysis, and static posturography. We evaluate the correlation of gait and posture parameters with electrophysiological and clinical parameters.

RESULTS

Foot height, step length, and stride length among gait parameters were inversely correlated with the TCNS. Anteroposterior range during eyes-closed and mediolateral distance and range during eyes-open and eyes-closed were inversely correlated with the sensory nerve action potential amplitude in the sural nerve. Mediolateral distance during eyes-open and eyes-closed was correlated with the compound muscle action potential amplitude in the peroneal nerve.

CONCLUSIONS

Gait parameters are associated with clinical parameters, and postural parameters are associated with electrophysiological parameters, particularly sensory NCS. Gait and postural analysis can be a useful tool for assessing the neurological status in DPN patients.

'Orbital volume restoration rate after orbital fracture'; a CT-based orbital volume measurement for evaluation of orbital wall reconstructive effect

PurposeTo evaluate the effect of orbital reconstruction and factors related to the effect of orbital reconstruction by assessing of orbital volume using orbital computed tomography (CT) in cases of orbital wall fracture.MethodsIn this retrospective study, 68 patients with isolated blowout fractures were evaluated. The volumes of orbits and herniated orbital tissues were determined by CT scans using a three-dimensional reconstruction technique (the Eclipse Treatment Planning System). Orbital CT was performed preoperatively, immediately after surgery, and at final follow ups (minimum of 6 months). We evaluated the reconstructive effect of surgery making a new formula, 'orbital volume reconstruction rate' from orbital volume differences between fractured and contralateral orbits before surgery, immediately after surgery, and at final follow up.ResultsMean volume of fractured orbits before surgery was 23.01±2.60 cm³ and that of contralateral orbits was 21.31±2.50 cm³ (P=0.005). Mean volume of the fractured orbits immediately after surgery was 21.29±2.42 cm³, and that of the contralateral orbits was 21.33±2.52 cm³ (P=0.921). Mean volume of fractured orbits at final follow up was 21.50±2.44 cm³, and that of contralateral orbits was 21.32±2.50 cm³ (P=0.668). The mean orbital volume reconstruction rate was 100.47% immediately after surgery and 99.17% at final follow up. No significant difference in orbital volume reconstruction rate was observed with respect to fracture site or orbital implant type. Patients that underwent operation within 14 days of trauma had a better reconstruction rate at final follow up than patients who underwent operation over 14 days after trauma (P=0.039).ConclusionComputer-based measurements of orbital fracture volume can be used to evaluate the reconstructive effect of orbital implants and provide useful quantitative information. Significant reduction of orbital volume is observed immediately after orbital wall reconstruction surgery and the reconstruction effect is maintained for more than minimum 6 months. Patients that undergo surgery within 14 days of trauma has better reconstruction rates at final follow up, which supports the need for early surgery.

Measurements of surgeons' exposure to ionizing radiation dose: comparison of conventional and mini C-arm fluoroscopy

This study was performed to measure the equivalent scattered radiation dose delivered to susceptible organs while simulating orthopaedic surgery using conventional and mini C-arm fluoroscopy. In addition, shielding effects on the thyroid, thymus, and gonad, and the direct exposure delivered to the patient's hands were also compared. A conventional and mini C-arms were installed in an operating room, and a hand and an operator phantom were used to simulate a patient's hand and a surgeon. Photoluminescence dosimeters were used to measure the equivalent dose by scattered radiation arriving at the thyroid, thymus, and gonad on a whole-body phantom in the position of the surgeon. Equivalent scattered radiation doses were measured in four groups: (1) unshielded conventional C-arm group; (2) unshielded mini C-arm group; (3) lead-shielded conventional C-arm group; and (4) lead-shielded mini C-arm group. Equivalent scattered radiation doses to the unshielded group were significantly lower in the mini C-arm group than those in the conventional C-arm group for all organs. The gonad in the lead-shielded conventional C-arm group showed the highest equivalent dose among operator-susceptible organs, and radiation dose was reduced by approximately 96% compared with that in the unshielded group. Scattered radiation was not detected in any susceptible organ in the lead-shielded mini C-arm group. The direct radiation dose to the hand phantom measured from the mini C-arm was significantly lower than that measured from the conventional C-arm. The results show that the equivalent scattered radiation dose to the surgeon's susceptible organs and the direct radiation dose to a patient's hand can be decreased significantly by using a mini C-arm rather than a conventional C-arm. However, protective lead garments, such as a thyroid shield and apron, should be applied to minimize radiation exposure to susceptible organs, even during use of mini C-arm fluoroscopy.

Reliability and validity of lower extremity computed tomography as a screening tool for osteoporosis

We evaluated the correlation between central bone mineral density (BMD) and peripheral bone attenuation using lower extremity computed tomography (CT). A good correlation was found between lower extremity CT and central BMD suggesting that CT is useful for screening osteoporosis, and that peripheral bone attenuation adequately reflects central BMD.

INTRODUCTION

This study aimed to evaluate the reliability and validity of CT as a screening tool for osteoporosis and to estimate the correlation between central BMD and peripheral bone attenuation using lower extremity CT.

METHODS

In total, 292 patients who underwent a lower extremity, lumbar spine, or abdomen and pelvic CT scan within a 3-month interval of a dual-energy X-ray absorptiometry (DEXA) examination were included. Following reliability testing, bone attenuation of the L1, L2, L3, L4, femoral head, femoral neck, greater trochanter, distal femur, proximal tibia, distal tibia, and talus was measured by placing a circular region of interest on the central part of each bony region on a coronal CT image. Partial correlation was used to assess the correlation between CT and DEXA after adjusting for age and body mass index.

RESULTS

In terms of reliability, all bone attenuation measurements, except the femoral neck, showed good to excellent interobserver reliability (intraclass correlation coefficients, 0.691-0.941). In terms of validity, bone attenuation of the L1 to L4, femoral neck, and greater trochanter on CT showed significant correlations with BMD of each area on DEXA (correlation coefficients, 0.399-0.613). Bone attenuation of the distal tibia and talus on CT showed significant correlations with BMD of all parts on DEXA (correlation coefficients, 0.493-0.581 for distal tibia, 0.396-0.579 for talus).

CONCLUSION

Lower extremity CT is a useful screening tool for osteoporosis, and peripheral bone attenuation on lower extremity CT adequately reflects central BMD on DEXA.

Spinal extradural arachnoid cyst

Spinal extradural arachnoid cysts are rare expanding lesions in the spinal canal. They usually present with progressive signs and symptoms caused by spinal cord compression if they enlarge. A comprehensive review about spinal extradural arachnoid cyst is made including the author's own case of a 59-year-old woman with a 6-month history of progressive back pain radiating to both legs. Key points concerning the possible pathogenesis including symptomatology, diagnosis, and the implications for treatment are highlighted. Surgical treatment is curative and this rare clinical entity should be considered in the differential diagnosis of spinal extradural lesions.

Dissemination of transferable CTX-M-type extended-spectrum beta-lactamase-producing Escherichia coli in Korea

AIMS

Among 365 Escherichia coli isolated in 2003, 31 cefotaxime-resistant isolates were obtained from clinical specimens taken from adults hospitalized in Busan, Korea. Six extended-spectrum beta-lactamase (ESBL)-producing isolates were investigated further to determine the mechanism of resistance.

METHODS AND RESULTS

These isolates were analysed by antibiotic susceptibility testing, pI determination, plasmid profiles, transconjugation test, PCR-restriction fragment length polymorphism (RFLP), enterobacterial repetitive consensus (ERIC)-PCR and DNA sequencing. All six of these isolates were found to contain the CTX-M-type ESBL genes. Five clinical isolates and their transconjugants produced CTX-M-3. One clinical isolate (K17391) and its transconjugant (trcK17391) produced CTX-M-15. Five clinical isolates also produced another TEM-1. One clinical isolate (K12776) also contained another TEM-52. CTX-M-3 ESBL gene was responsible for the resistance to piperacillin, cephalothin, cefotaxime, cefepime and aztreonam. CTX-M-15 or TEM-52 was especially responsible for the resistance to ceftazidime.

CONCLUSIONS

These results appear to represent the in vivo evolution of CTX-M-type beta-lactamase genes (bla(CTX-M-3) --> bla(CTX-M-15)) under the selective pressure of antimicrobial therapy (especially ceftazidime). PCR-RFLP is a reliable method to discriminate CTX-M-15 gene from CTX-M-3 gene. ERIC-PCR analysis revealed that dissemination of CTX-M-3 was not due to a clonal outbreak of a resistant strain but to the intra-species spread of resistance to piperacillin, cephalothin, cefotaxime, cefepime and aztreonam in Korea.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report of the occurrence of CTX-M-1 cluster ESBLs in Korea. A more comprehensive survey of these ESBL types from Korea is urgently needed because of the in vivo evolution of CTX-M-15 from CTX-M-3. The emergence of these CTX-M-type ESBLs suggests that diagnostic laboratories should screen for ESBLs with ceftazidime as well as cefotaxime; they should still perform clavulanate synergy tests on resistant isolates.

Investigation of a nosocomial outbreak of Acinetobacter baumannii producing PER-1 extended-spectrum beta-lactamase in an intensive care unit

We investigated an outbreak of Acinetobacter baumannii in an adult intensive care unit of Kosin University Gospel Hospital in Busan, Republic of Korea. The outbreak involved 10 cases of infection by A. baumannii producing PER-1 extended-spectrum beta-lactamase over a seven-month period, and was caused by a single pulsed-field gel electrophoresis clone. The epidemic isolates were characterized by slight synergy between clavulanic acid and cefepime. Isoelectric focusing of crude bacterial extracts detected two nitrocefin-positive bands with pI values of 8.0 and 5.3. Polymerase chain reaction amplification and characterization of the amplicons by restriction analysis and direct sequencing indicated that the epidemic isolates carried a bla(PER-1) determinant. The epidemic isolates were characterized by a multidrug-resistant phenotype that remained unchanged over the outbreak, including penicillins, beta-lactam/beta-lactamase inhibitor, extended-spectrum cephalosporins and monobactams. Isolation of infected patients and appropriate carbapenem therapy were successful in ending the outbreak. Our report indicates that the bla(PER-1) resistance determinant may become an emerging therapeutic problem.

[Comparison of percutaneous manual and endoscopic laser diskectomy with chemonucleolysis and automated nucleotomy]

The combination of percutaneous manual and endoscopic Ho:YAG laser discectomy (PELD) is a new minimal intervention technique in treating patients with herniated lumbar discs that do not penetrate the posterior longitudinal ligament. The results in 100 patients treated with PELD were compared randomly with those in 100 patients treated by chemonucleolysis with chymopapain (CN) and 100 patients treated by automated percutaneous lumbar discectomy (APLD) at the same hospital. We followed the 300 patients postoperatively for 1 year, with physical examination, postoperative plain lumbosacral radiography, CT, MRI and a self-assessment questionnaire. Some 68% of the patients in the PELD group considered the outcome as excellent or good and 23% as fair; the corresponding figures were 55% and 27% in the CN group, and 48% and 32% in the APLD group. Nine percent of the patients in the PELD group underwent open microdiscectomy or were suffering from back pain with sciatica, compared with 18% in the CN group and 20% in the APLD group. PELD showed better extraction of the hernia mass than APLD and a lower rate of low back pain and less decrease in disc height than CN.