Commissioning of total body irradiation using plastic bead bags.

The goal of total body irradiation (TBI) is to deliver a dose to the whole body with uniformity within ±10%. The purpose of this study was to establish the technique of TBI using plastic bead bags. A lifting TBI bed, Model ORP-TBI-MN, was used. The space between the patient's body and the acrylic walls of the bed was filled with polyacetal bead bags. Patients were irradiated by a 10 MV photon beam with a source to mid-plane distance of 400 cm. The monitor unit (MU) was calculated by dose-per-MU, tissue-phantom-ratio and a spoiler factor measured in solid water using an ionization chamber. The phantom-scatter correction factor, off-center ratio and the effective density of the beads were also measured. Diode detectors were used for in vivo dosimetry (IVD). The effective density of the beads was 0.90 ± 0.09. The point doses calculated in an I'mRT phantom with and without heterogeneity material showed good agreement, with measurements within 3%. An end-to-end test was performed using a RANDO phantom. The mean ± SD (range) of the differences between the calculated and IVD-measured mid-plane doses was 1.1 ± 4.8% (-5.9 to 5.0%). The differences between the IVD-measured doses and the doses calculated with Acuros XB of the Eclipse treatment planning system (TPS) were within 5%. For two patients treated with this method, the differences between the calculated and IVD-measured doses were within ±6% when excluding the chest region. We have established the technique of TBI using plastic bead bags. The TPS may be useful to roughly estimate patient dose.

Successful continuous nivolumab therapy for metastatic non-small cell lung cancer after local treatment of oligometastatic lesions.

The patient in this report was a 57-year-old man with metastatic non-small cell lung cancer (NSCLC). After no response to two lines of systemic chemotherapy, he was treated with nivolumab as third-line therapy, which resulted in a partial response. After 17 months of nivolumab treatment, he developed bone metastasis in his left femur which was treated with radiation therapy. Nivolumab was restarted after radiation therapy. Four months after radiation therapy, he developed another metastatic lesion in the small intestine which was surgically resected. Because there were no recurrent NSCLC lesions after surgical resection, nivolumab was restarted again. At 18 months after surgery, there were no recurrent NSCLC lesions. Immunohistochemical analysis of peritumoral T lymphocytes showed higher expression of T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3) and lymphocyte activation gene 3 (LAG-3) in recurrent lesions of bone and small intestine than in primary lesions. Upregulation of TIM-3 and LAG-3 could be associated with mechanisms of adaptive resistance to nivolumab in this case. Here, we report a successful case of continued nivolumab therapy with remission after local treatments consisting of radiation therapy and surgical resection for oligometastases. Continuation of immune checkpoint inhibitor (ICI) treatment may be worth considering if oligometastases can be controlled. KEY POINTS: Significant findings of the study We report a successful case of continued nivolumab treatment with remission after local treatment (radiation therapy and surgical resection) for oligometastases. What this study adds Upregulation of T cell immunoglobulin and mucin domain-containing protein 3 and lymphocyte-activation gene 3 could be associated with mechanisms of adaptive resistance to nivolumab.

Chemoradiotherapy followed by consolidation chemotherapy involving paclitaxel and carboplatin and in FIGO stage IIIB/IVA cervical cancer patients.

OBJECTIVE: To evaluate the efficacy and toxicity of paclitaxel plus carboplatin (TC)-based concurrent chemoradiotherapy (CCRT) followed by consolidation chemotherapy in the International Federation of Gynecology and Obstetrics (FIGO) stage IIIB/IVA cervical cancer patients. METHODS: We reviewed the medical records of FIGO stage IIIB/IVA cervical cancer patients (n=30) who had been intended to be treated with TC-based CCRT followed by consolidation chemotherapy (TC-CCRT-group) from April 2012-May 2016. Patients who had been treated with CCRT involving a single platinum agent (CCRT-group; n=52) or definitive radiotherapy alone (RT-group; n=74) from January 1997-September 2012 were also identified and used as historical controls. Survival was calculated using the Kaplan-Meier method and compared using the log-rank test. RESULTS: Of the 30 patients included in the TC-CCRT-group, 22 patients (73.3%) completed the planned TC-based CCRT. The most frequently observed acute grade 3/4 hematological toxicities were leukopenia and neutropenia, and diarrhea was the most common acute grade 3/4 non-hematological toxicity. After a median follow-up of 35 months, 9 patients (30.0%) had developed recurrent disease. The patients' estimated 3-year progression-free survival (PFS) and overall survival (OS) rates were 67.9% and 90.8%, respectively. In comparisons with historical control groups, the survival outcomes of TC-CCRT-group was significantly superior to CCRT-group in terms of OS (p=0.011) and significantly superior to RT-group in terms of both PFS (p=0.009) and OS (p<0.001). CONCLUSION: TC-based CCRT followed by consolidation chemotherapy is safe and effective. A randomized controlled study needs to be conducted to further evaluate the efficacy of this multimodal approach in this patient population.

Structure of conjugated polyketone reductase from Candida parapsilosis IFO 0708 reveals conformational changes for substrate recognition upon NADPH binding.

Conjugated polyketone reductase C2 (CPR-C2) from Candida parapsilosis IFO 0708, identified as a nicotinamide adenine dinucleotide phosphate (NADPH)-dependent ketopantoyl lactone reductase, belongs to the aldo-keto reductase superfamily. This enzyme reduces ketopantoyl lactone to D-pantoyl lactone in a strictly stereospecific manner. To elucidate the structural basis of the substrate specificity, we determined the crystal structures of the apo CPR-C2 and CPR-C2/NADPH complex at 1.70 and 1.80 Å resolutions, respectively. CPR-C2 adopted a triose-phosphate isomerase barrel fold at the core of the structure. Binding with the cofactor NADPH induced conformational changes in which Thr27 and Lys28 moved 15 and 5.0 Å, respectively, in the close vicinity of the adenosine 2'-phosphate group of NADPH to form hydrogen bonds. Based on the comparison of the CPR-C2/NADPH structure with 3-α-hydroxysteroid dehydrogenase and mutation analyses, we constructed substrate binding models with ketopantoyl lactone, which provided insight into the substrate specificity by the cofactor-induced structure. The results will be useful for the rational design of CPR-C2 mutants targeted for use in the industrial manufacture of ketopantoyl lactone.

Crystal structure of conjugated polyketone reductase (CPR-C1) from Candida parapsilosis IFO 0708 complexed with NADPH.

Conjugated polyketone reductase (CPR-C1) from Candida parapsilosis IFO 0708 is a member of the aldo-keto reductase (AKR) superfamily and reduces ketopantoyl lactone to d-pantoyl lactone in a NADPH-dependent and stereospecific manner. We determined the crystal structure of CPR-C1.NADPH complex at 2.20 Å resolution. CPR-C1 adopted a triose-phosphate isomerase (TIM) barrel fold at the core of the structure in which Thr25 and Lys26 of the GXGTX motif bind uniquely to the adenosine 2'-phosphate group of NADPH. This finding provides a novel structural basis for NADPH binding of the AKR superfamily.

The usefulness of an independent patient-specific treatment planning verification method using a benchmark plan in high-dose-rate intracavitary brachytherapy for carcinoma of the uterine cervix.

To develop an easy independent patient-specific quality assurance (QA) method using a benchmark plan for high-dose-rate intracavitary brachytherapy for cervix cancer, we conducted benchmark treatment planning with various sizes and combinations of tandem-ovoid and tandem-cylinder applications with 'ideal' geometry outside the patient. Two-dimensional-based treatment planning was conducted based on the Manchester method. We predicted the total dwell time of individual treatment plans from the air kerma strength, total dwell time and prescription dose of the benchmark plan. In addition, we recorded the height (dh), width (dw) and thickness (dt) covered with 100% isodose line. These parameters were compared with 169 and 29 clinical cases for tandem-ovoid or tandem-cylinder cases, respectively. With regard to tandem-ovoid cases, differences in total dwell time, dh, dt and dw between benchmark and individual plans were on average -0.2% ± 3.8%, -1.0 mm ± 2.6 mm, 0.8 mm ± 1.3 mm and -0.1 mm ± 1.5 mm, respectively. With regard to tandem-cylinder cases, differences in total dwell time, dh(front) (the distance from tandem tip to tandem ring), dt and dw between benchmark and individual plans were on average -1.5% ± 3.1%, -1.5 mm ± 4.9 mm, 0.1 mm ± 1.0 mm and 0.2 mm ± 0.8 mm, respectively. Of two cases, more than 13% differences in total dwell time were observed between benchmark plans and the clinical cases, which turned out to be due to the use of the wrong source position setting. These results suggest that our method is easy and useful for independent verification of patient-specific treatment planning QA.

Post-treatment follow-up procedures in cervical cancer patients previously treated with radiotherapy.

PURPOSE: We investigated the role of physical examination, CT scan, chest X-ray, and Pap smear in the routine follow-up program for cervical cancer patients previously treated with radiotherapy. METHODS: The records of women who had developed recurrent cervical cancer after radiotherapy were retrospectively reviewed. The optimal procedure for the detection of recurrence was evaluated according to the disease-free interval (DFI). Survival analysis was performed based on the Kaplan-Meier method and comparisons between groups were made using the log-rank test. RESULTS: A total of 146 recurrent cervical cancer patients were included in our database. The majority of recurrences were diagnosed either by symptoms, physical examination, or CT scan. The patients whose recurrent disease was detected by Pap smear, physical examination, or CT scan had a significantly longer survival than those detected by symptoms. When analyzed according to DFI, physical examination, and CT scan led to the detection of recurrence in patients with a DFI of 1-5 years. In contrast, chest X-ray and Pap smear only had a clinical impact on the diagnosis of recurrence in patients with a DFI of 1-2 years. CONCLUSIONS: Chest X-ray and Pap smear can be routinely performed for the first 2 years after radiotherapy, but can be omitted or used sparingly thereafter.

Crystal structure of the ATPPase subunit and its substrate-dependent association with the GATase subunit: a novel regulatory mechanism for a two-subunit-type GMP synthetase from Pyrococcus horikoshii OT3.

Guanosine 5'-monophosphate synthetase(s) (GMPS) catalyzes the final step of the de novo synthetic pathway of purine nucleotides. GMPS consists of two functional units that are present as domains or subunits: glutamine amidotransferase (GATase) and ATP pyrophosphatase (ATPPase). GATase hydrolyzes glutamine to yield glutamate and ammonia, while ATPPase utilizes ammonia to convert adenyl xanthosine 5'-monophosphate (adenyl-XMP) into guanosine 5'-monophosphate. Here we report the crystal structure of PH-ATPPase (the ATPPase subunit of the two-subunit-type GMPS from the hyperthermophilic archaeon Pyrococcus horikoshii OT3). PH-ATPPase consists of two domains (N-domain and C-domain) and exists as a homodimer in the crystal and in solution. The N-domain contains an ATP-binding platform called P-loop, whereas the C-domain contains the xanthosine 5'-monophosphate (XMP)-binding site and also contributes to homodimerization. We have also demonstrated that PH-GATase (the glutamine amidotransferase subunit of the two-subunit-type GMPS from the hyperthermophilic archaeon P. horikoshii OT3) alone is inactive, and that all substrates of PH-ATPPase except for ammonia (Mg(2+), ATP and XMP) are required to stabilize the active complex of PH-ATPPase and PH-GATase subunits.

Expression, purification, crystallization and preliminary X-ray analysis of conjugated polyketone reductase C2 (CPR-C2) from Candida parapsilosis IFO 0708.

Conjugated polyketone reductase C2 (CPR-C2) from Candida parapsilosis IFO 0708 is a member of the NADPH-dependent aldo-keto reductase (AKR) superfamily and catalyzes the stereospecific reduction of ketopantoyl lactone to d-pantoyl lactone. A diffraction-quality crystal of recombinant CPR-C2 was obtained by the sitting-drop vapour-diffusion method using PEG 3350 as the precipitant. The crystal diffracted X-rays to 1.7 angstrom resolution on beamline NW12A of the Photon Factory-Advanced Ring (Tsukuba, Japan). The crystal belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 55.02, b = 68.30, c = 68.93 angstrom. The Matthews coefficient (V(M) = 1.76 angstrom(3) Da(-1)) indicated that the crystal contained one CPR-C2 molecule per asymmetric unit.