Pan-Asian adapted ESMO Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with gastric cancer

The European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with gastric cancer (GC), published in late 2022 and the updated ESMO Gastric Cancer Living Guideline published in July 2023, were adapted in August 2023, according to previously established standard methodology, to produce the Pan-Asian adapted (PAGA) ESMO consensus guidelines for the management of Asian patients with GC. The adapted guidelines presented in this manuscript represent the consensus opinions reached by a panel of Asian experts in the treatment of patients with GC representing the oncological societies of China (CSCO), Indonesia (ISHMO), India (ISMPO), Japan (JSMO), Korea (KSMO), Malaysia (MOS), the Philippines (PSMO), Singapore (SSO), Taiwan (TOS) and Thailand (TSCO), coordinated by ESMO and the Japanese Society of Medical Oncology (JSMO). The voting was based on scientific evidence and was independent of the current treatment practices, drug access restrictions and reimbursement decisions in the different Asian regions represented by the 10 oncological societies. The latter are discussed separately in the manuscript. The aim is to provide guidance for the optimisation and harmonisation of the management of patients with GC across the different regions of Asia, drawing on the evidence provided by both Western and Asian trials, whilst respecting the differences in screening practices, molecular profiling and age and stage at presentation. Attention is drawn to the disparity in the drug approvals and reimbursement strategies, between the different regions of Asia.

Chemotherapy after nivolumab for advanced gastric cancer (REVIVE): a prospective observational study

BACKGROUND

Nivolumab therapy is a standard-of-care treatment for heavily pretreated patients with advanced gastric cancer (AGC). Previous studies have reported improvement in the objective response rate to chemotherapy after nivolumab therapy for other types of cancer. This study evaluated the efficacy and safety of chemotherapy after nivolumab therapy in AGC.

PATIENTS AND METHODS

We conducted a prospective, multicenter, observational study in pretreated patients with nivolumab-refractory or -intolerant AGC. Patients received irinotecan, oxaliplatin-containing regimens, or trifluridine/tipiracil. The primary endpoint was overall survival.

RESULTS

A total of 199 patients were included (median age: 69 years; male: 70%; female: 30%). Median overall survival and progression-free survival were 7.5 months [95% confidence interval (CI): 6.7-9.7 months] and 2.9 months (95% CI: 2.2-3.5 months), respectively. Objective response and disease control rates were 16.8% (95% CI: 11.6% to 23.6%) and 18.9% (95% CI: 38.9% to 54.6%), respectively. A prognostic index using alkaline phosphatase and the Glasgow Prognostic Score was generated to classify patients into three risk groups (good, moderate, and poor). The hazard ratios of the moderate and poor groups to the good group were 1.88 (95% CI: 1.22-2.92) and 3.29 (95% CI: 1.92-5.63), respectively. At the initiation of chemotherapy, 42 patients had experienced immune-related adverse events due to prior nivolumab therapy. The most common grade 3-4 adverse events were neutropenia (7.5%), anemia (8.0%), and anorexia (7.5%).

CONCLUSIONS

The administration of cytotoxic chemotherapy after nivolumab therapy may give rise to a synergistic antitumor effect in AGC. Further investigation is warranted to confirm these findings.

Novel Functional Peptide for Next-Generation Vital Pulp Therapy

Although vital pulp therapy should be performed by promoting the wound-healing capacity of dental pulp, existing pulp-capping materials were not developed with a focus on the pulpal repair process. In previous investigations of wound healing in dental pulp, we found that organic dentin matrix components (DMCs) were degraded by matrix metalloproteinase-20, and DMC degradation products containing protein S100A7 (S100A7) and protein S100A8 (S100A8) promoted the pulpal wound-healing process. However, the direct use of recombinant proteins as pulp-capping materials may cause clinical problems or lead to high medical costs. Thus, we hypothesized that functional peptides derived from recombinant proteins could solve the problems associated with direct use of such proteins. In this study, we identified functional peptides derived from the protein S100 family and investigated their effects on dental pulp tissue. We first performed amino acid sequence alignments of protein S100 family members from several mammalian sources, then identified candidate peptides. Next, we used a peptide array method that involved human dental pulp stem cells (hDPSCs) to evaluate the mineralization-inducing ability of each peptide. Our results supported the selection of 4 candidate functional peptides derived from proteins S100A8 and S100A9. Direct pulp-capping experiments in a rat model demonstrated that 1 S100A8-derived peptide induced greater tertiary dentin formation compared with the other peptides. To investigate the mechanism underlying this induction effect, we performed liquid chromatography-tandem mass spectrometry analysis using hDPSCs and the S100A8-derived peptide; the results suggested that this peptide promotes tertiary dentin formation by inhibiting inflammatory responses. In addition, this peptide was located in a hairpin region on the surface of S100A8 and could function by direct interaction with other molecules. In summary, this study demonstrated that a S100A8-derived functional peptide promoted wound healing in dental pulp; our findings provide insights for the development of next-generation biological vital pulp therapies.

PL02.4.A International validation study of an EORTC instrument measuring instrumental activities of daily living (IADL) in patients with brain tumours: EORTC IADL-BN32

Background

Brain tumour patients often have neurocognitive deficits which can result in problems with activities in daily living that are cognitively complex. Currently, no valid and reliable brain tumour-specific instrument to measure these instrumental activities of daily living (IADL) is available, but such an instrument is being developed. This study aimed to validate the EORTC IADL-BN32 questionnaire, comprising five multi-item and two single item scales, in a large set of international brain tumour patients.

Material and Methods

This international study was conducted in 10 countries worldwide. Primary and metastatic brain tumour patients and their proxies were requested to complete the EORTC IADL-BN32 and a subjective cognitive questionnaire (MOS COG-R) at multiple time points. Several psychometric properties were evaluated with baseline data, including the structural validity (bi-factor confirmatory factor analysis [CFA]), reliability (internal consistency), construct validity (known groups comparisons) and patient-proxy congruency (intra-class correlation coefficients [ICC], Spearman's correlation).

Results

At baseline, 326 patients ( 30% low-grade glioma, 37% high-grade glioma (HGG) and 33% brain metastases) and 311 proxies completed the EORTC IADL-BN32. The bi-factor CFA was found to have a satisfactory model fit (CFI=0.92 and TLI=0.90), and other parameters indicated a good fit (RMSEA=0.08 and SRMR=0.05), thereby validating the preliminary scale structure, but also an IADL sum score. The multi-item scales showed good (0.9>α≥0.8) to excellent (α≥0.9) internal consistency (range α=0.86-0.97). Known groups comparisons analyses regarding patient’s cognitive status (indications vs. no cognitive impairment), subjective cognitive complaints (MOS COG-R ≤30 vs. >30), basic ADL (Barthel Index <100 vs. 100) and performance status (KPS <70 vs. ≥70) showed significant differences on all IADL outcome measures in line with a priori defined hypotheses. On a group level, patient and proxy ratings had moderate to strong correlations, however, proxies tended to report more problems on all scales. The ICCs showed moderate to good congruency between patients and proxies (range ICC: 0.63-0.81).

Conclusion

The evaluated psychometric properties support the current scale structure of the EORTC IADL-BN32. Additional psychometric properties with longitudinal data are needed, such as test-retest reliability and responsiveness, to further validate the EORTC-IADL BN32 questionnaire.

OS05.4.A Do neurocognitive deficits explain the differences between brain tumour patients and their proxies assessing the patient’s I-ADL?

BACKGROUND

Neurocognitive deficits are common among brain tumour patients, and may impact on patient awareness of deficits in instrumental activities in daily life (IADL). This study aimed to examine differences between patient-reported and proxy-reported assessments of the patient’s performance of IADL, and whether the level of (dis)agreement is associated with neurocognitive deficits.

MATERIAL AND METHODS

A phase III EORTC questionnaire measuring IADL in brain tumour patients (EORTC IADL-BN32) and six neurocognitive test measures were administered as part of a larger multicentre international study designed to develop a brain tumour specific IADL questionnaire. Bland-Altman plots and Mann-Whitney U tests were used to evaluated patient- and proxy-reported IADL on a group level. Subsequently, Mann-Whitney U tests were performed to compare patient-proxy difference scores (patient IADL score - their proxy IADL score) between patients who were considered clearly neurocognitively impaired (≥2 neurocognitive test measures; ≤2.0 SD below healthy controls) and patients who were not. Furthermore, multinomial logistic regression analyses were performed to examined which sociodemgraphic, clinical, and particularly neurocognitive variables were independently associated with patients and proxies differing in their evaluation of patient’s IADL.

RESULTS

Patients (N=81) and proxies (N=81), on group level, did not significantly differ on either the IADL individual item or scale scores. However, significant differences were found on patient-proxy difference scores between patients who were (N=37) and were not (N=44) considered clearly neurocognitively impaired for 10/32 individual items and one of the scales (i.e. Scale 4: Administrative tasks), all showing that the proxies of clearly neurocognitively impaired patients reported more problems relative to the patients themselves, compared to proxies of patients not clearly neurocognitively impaired. Furthermore, for each scale, a neurocognitive variable, either impaired information processing speed, cognitive flexibility, verbal fluency or the number of neurocognitive test measures impaired, was found to be independently associated with proxies reporting more problems. For 4/5 scales, a clinical variable was additionally independently associated with proxies reporting more problems. Only one variable was independently associated with patient reporting more problems, namely being in active treatment was found to be associated with patients reporting more problems on Scale 4: Administrative tasks.

CONCLUSION

Results imply a consistent trend of clearly neurocognitively impaired patients underreporting problems with IADL compared to their proxies. It would therefore be advised to administer both the patient- and proxy-version of the EORTC IADL-BN32, particularly if neurocognitive deficits are presumed.

Prevalence of Multiple-Level Spondylolysis and the Bone Union Rates among Growth-Stage Children with Lower Back Pain

Introduction

Lumbar spondylolysis is usually single level, and only a few multiple-level cases have been reported. We investigated the frequency of multiple-level spondylolysis and the bone union rates among growth-stage children with lower back pain (LBP).

Methods

The subjects were growth-stage children examined for LBP between April 2013 and December 2018. All patients with LBP persisting for at least 2 weeks and severe enough to make playing sports difficult underwent lumbar plain radiogram, computed tomography, and magnetic resonance imaging. The cases diagnosed as multiple-level spondylolysis and classified as early or progressive stage received conservative treatment to achieve bone union.

Results

A total of 782 growth-stage children were examined for LBP. Of them, 243 children (31.1%) were diagnosed with lumbar spondylolysis. Of these 243 children, 23 (9.5%) children had multiple-level spondylolysis. Of the children diagnosed with multiple-level spondylolysis, most children (87.0%) had pars defects in the early or progressive stage in which bone union could be expected. Most children (78.3%) had pars defects in the terminal stage and combined with these defects, had pars defects in the early or progressive stage at a different spinal level.

Twenty children diagnosed with multiple-level spondylolysis who also had pars defects in the early or progressive stage received conservative treatment for bone union, which was achieved in 31 of 39 sites (79.5%). The bone union rate by stage was 92.9% (26 of 28 sites) in the early stage and 45.5% (5 of 11 sites) in the progressive stage.

Conclusions

In cases of multiple-level spondylolysis, bone union is likely to be achieved with conservative treatment when the pars defects are in the early or progressive stage. Therefore, the first choice of treatment should be conservative treatment to achieve bone union, the same for single-level spondylolysis.

Impact of tumor growth rate during preceding treatment on tumor response to nivolumab or irinotecan in advanced gastric cancer

Background

Nivolumab (NIVO) and irinotecan (IRI) are standard treatments for refractory advanced gastric cancer (AGC); however, it is unclear which drug should be administered first or in which cases. The tumor growth rate (TGR) during preceding treatment is reported to be associated with tumor response in metastatic colorectal cancer patients treated with regorafenib or trifluridine/tipiracil, suggesting that TGR may be useful for drug selection. Therefore, we evaluated the association between TGR during preceding treatment and the tumor response to NIVO or IRI.

Patients and methods

We retrospectively evaluated consecutive AGC patients treated with NIVO or IRI and divided them into slow-growing (Slow) and rapid-growing (Rapid) groups according to TGR and the presence or absence of new lesions (NL+/NL−, respectively) during preceding treatment (Slow group: NL− with low TGR <0.30%/day; Rapid group: NL+ or high TGR ≥0.30%/day).

Results

A total of 117 patients (Rapid/Slow groups, 72/45; NIVO/IRI groups, 32/85) were eligible. All baseline characteristics except peritoneal metastases were similar between patients treated with NIVO and IRI in the Rapid and Slow groups. The response rate was significantly higher in patients treated with NIVO compared with IRI [31%/3%; odds ratio (OR), 13.8; P = 0.01; adjusted OR, 52; P = 0.002] in the Slow group, but there was no difference between patients treated with NIVO and IRI (5%/8%; OR, 0.68; P = 0.73; adjusted OR, 0.94; P = 0.96) in the Rapid group. Disease control rate, progression-free survival, and overall survival were consistent with these results.

Conclusions

Our findings suggest that NIVO treatment is a more favorable option for patients with slow-growing tumors, and NIVO and IRI are similarly recommended for patients with rapid-growing tumors in refractory AGC. TGR and NL emergence during preceding treatment may be helpful for drug selection and warrant further investigation.

•

NIVO and IRI are standard treatments for refractory AGC, although it is unclear which should be administered first.

•

TGR may be useful for drug selection, therefore we evaluated the association between TGR and the tumor response to NIVO or IRI.

•

In the Slow group, the response rate (RR) was significantly higher in patients treated with NIVO compared with IRI.

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In the Rapid group, there was no significant difference in RR between the NIVO and IRI groups.

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TGR and NL emergence during preceding treatment may be useful for drug selection.

P3112The oral administration of colchicine prevents the progression of aortic aneurysm

Objective

The pathogenesis of aortic aneurysm (AA) is characterized by the chronic inflammation of the aortic wall with the accumulation of macrophages and the degradation of the extracellular matrix (ECM) including elastin. Colchicine (COL) is an alkaloid derived from the plant Lily family Colchicum autumnale, and it is known for anti-inflammatory effects. Plant extracts containing COL have been used in the treatment of gout from ancient period. Currently, pseudogout, familial Mediterranean fever, Behçet's disease and pericarditis are also treated by COL. Furthermore, recent evidence suggests the use of COL for secondary prevention of cardiovascular disease, and the phase 3 clinical trial for it has begun. The objective of this study is to investigate whether COL could prevent the progression of aortic aneurysms.

Methods

In vitro: Macrophages (J774A.1 cell line) stimulated TNF-α 24 hours before and smooth muscle cell (SMC) were cultured with 10 ng/mL COL, and the gene expression of inflammatory cytokines involved in the AA formation was measured 24 hours later.

In vivo: Male apolipoprotein E-deficient mice (30–35 weeks of age) were infused with angiotensin II for 28 days. COL (20 μg/kg/d) or saline (NS, as a control) was administered orally to the mice every day (COL group, n=8; NS group, n=8). Aortic diameter was measured by echography every week and all mice were sacrificed and their thoracoabdominal aorta was harvested at the last day of the administration period and elastin content, MMP activitis, and levels of inflammatory cytokines involved in the AA formation were measured.

Results

In vitro: The gene expression of IL-1β, TNF-α, MCP-1, NF-κB, MMP-9 in the macrophages was significantly decreased in the COL group. The gene expression of Lox, TIMP-2 in the SMC were significantly increased in COL group.

In vivo: Aortic diameter measured by echography every week was significantly suppressed in the COL group (2.25 vs 2.81 mm, p<0.05). The incidence of AA was decreased in the COL group (62.5% vs 100%). COL significantly suppressed the degeneration of aortic elastin in EVG staining (p<0.05). There is no significant difference in the enzyme activities of MMP-2 and MMP-9 between COL and NS groups, but IL-1β (54.4 vs 81.4, p<0.05), TNF-α (31.0 vs 60.6, p<0.05), MCP-1 (258.2 vs 411.2, p<0.05), NLRP3 inflammasome (7.1 vs 8.6, p<0.05), NE (1.5 vs 2.4, p<0.05), MPO (44.9 vs 48.1, p<0.05) were decreased in the COL group.

Discussion

In AA model mice, COL seems to suppress the progression of AA by anti-infammation and preservation of the ECM structure through the inhibition of NLRP3 inflammasome. That NLRP3 inflammasome activation leads to the progression of AA in AA model mice was previously reported and this supports out results.

Methods and Results (in vivo)

Conclusions

This results suggest that the oral administration of COL prevents the progression of AA in AA model mice and it is expected as a novel therapeutic agent for AA.

Acknowledgement/Funding

JSPS KAKENHI Grant

Intratumoural immune cell landscape in germinoma reveals multipotent lineages and exhibits prognostic significance

AIMS

Alterations in microenvironments are a hallmark of cancer, and these alterations in germinomas are of particular significance. Germinoma, the most common subtype of central nervous system germ cell tumours, often exhibits massive immune cell infiltration intermingled with tumour cells. The role of these immune cells in germinoma, however, remains unknown.

METHODS

We investigated the cellular constituents of immune microenvironments and their clinical impacts on prognosis in 100 germinoma cases.

RESULTS

Patients with germinomas lower in tumour cell content (i.e. higher immune cell infiltration) had a significantly longer progression-free survival time than those with higher tumour cell contents (P = 0.03). Transcriptome analyses and RNA in-situ hybridization indicated that infiltrating immune cells comprised a wide variety of cell types, including lymphocytes and myelocyte-lineage cells. High expression of CD4 was significantly associated with good prognosis, whereas elevated nitric oxide synthase 2 was associated with poor prognosis. PD1 (PDCD1) was expressed by immune cells present in most germinomas (93.8%), and PD-L1 (CD274) expression was found in tumour cells in the majority of germinomas examined (73.5%).

CONCLUSIONS

The collective data strongly suggest that infiltrating immune cells play an important role in predicting treatment response. Further investigation should lead to additional categorization of germinoma to safely reduce treatment intensity depending on tumour/immune cell balance and to develop possible future immunotherapies.

Single-center Experience of Living-donor Liver Transplantation in Patients Receiving Maintenance Renal Replacement Therapy

BACKGROUND

For most patients with liver failure receiving maintenance renal replacement therapy (RRT), treatment with living-donor liver transplantation (LDLT) alone is indicated in Japan.

MATERIAL AND METHODS

We retrospectively reviewed patients who underwent LDLT while receiving RRT in our hospital.

RESULTS

Three of the 5 patients who underwent LDLT while on RRT died during the first year after transplantation.

CONCLUSIONS

The indications for liver transplantation in patients on RRT require careful examination.

Membrane Fouling Potentials of an Exoelectrogenic Fouling-Causing Bacterium Cultured With Different External Electron Acceptors

Integrated microbial fuel cell (MFC) and membrane bioreactor (MBR) systems are a promising cost-effective and energy-saving technology for wastewater treatment. Membrane fouling is still an important issue of such integrated systems in which aeration (oxygen) is replaced with anode electrodes (anodic respiration). Here, we investigated the effect of culture conditions on the membrane fouling potential of fouling-causing bacteria (FCB). In the present study, Klebsiella quasipneumoniae strain S05, which is an exoelectrogenic FCB isolated from a MBR treating municipal wastewater, was cultured with different external electron acceptors (oxygen, nitrate, and solid-state anode electrode). As results, the fouling potential of S05 was lowest when cultured with anode electrode and highest without any external electron acceptor (p < 0.05, respectively). The composition of soluble microbial products (SMP) and extracellular polymeric substances (EPS) was also dependent on the type of electron acceptor. Protein and biopolymer contents in SMP were highly correlated with the fouling potential (R² = 0.73 and 0.81, respectively). Both the fouling potential and yield of protein and biopolymer production were significantly mitigated by supplying electron acceptors sufficiently regardless of its types. Taken together, the aeration of MBR could be replaced with solid-state anode electrodes without enhancement of membrane fouling, and the anode electrodes must be placed sufficiently to prevent the dead spaces in the integrated reactor.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the management of patients with metastatic oesophageal cancer: a JSMO-ESMO initiative endorsed by CSCO, KSMO, MOS, SSO and TOS

The most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of oesophageal cancer was published in 2016, and covered the management and treatment of local/locoregional disease, limited disease, locally advanced disease and the management of advanced/metastatic disease. At the ESMO Asia Meeting in November 2017 it was decided by both ESMO and the Japanese Society of Medical Oncology (JSMO) to convene a special guidelines meeting immediately after the JSMO Annual Meeting in 2018. The aim was to adapt the ESMO 2016 guidelines to take into account the ethnic differences associated with the treatment of metastatic oesophageal cancer in Asian patients. These guidelines represent the consensus opinions reached by experts in the treatment of patients with metastatic oesophageal cancer representing the oncological societies of Japan (JSMO), China (CSCO), Korea (KSMO), Malaysia (MOS), Singapore (SSO) and Taiwan (TOS). The voting was based on scientific evidence, and was independent of both the current treatment practices and the drug availability and reimbursement situations in the individual participating Asian countries.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the management of patients with metastatic gastric cancer: a JSMO-ESMO initiative endorsed by CSCO, KSMO, MOS, SSO and TOS

The most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of gastric cancer (GC) was published in 2016, and covered the management and treatment of local, locoregional, locally advanced and metastatic disease. At the ESMO Asia Meeting in November 2017 it was decided by both ESMO and The Japanese Society of Medical Oncology (JSMO) to convene a special guidelines meeting immediately after the JSMO Annual Meeting in 2018. The aim was to adapt the ESMO 2016 guidelines to take into account the ethnic differences associated with the treatment of metastatic GC in Asian patients. These guidelines represent the consensus opinions reached by experts in the treatment of patients with metastatic GC representing the oncological societies of Japan (JSMO), China (CSCO), Korea (KSMO), Malaysia (MOS), Singapore (SSO) and Taiwan (TOS). The voting was based on scientific evidence and was independent of both the current treatment practices and the drug availability and reimbursement situations in the individual participating Asian countries.

Aggregation ability of three phylogenetically distant anammox bacterial species

Anaerobic ammonium-oxidizing (anammox) bacteria are well known for their aggregation ability. However, very little is known about cell surface physicochemical properties of anammox bacteria and thus their aggregation abilities have not been quantitatively evaluated yet. Here, we investigated the aggregation abilities of three different anammox bacterial species: "Candidatus Brocadia sinica", "Ca. Jettenia caeni" and "Ca. Brocadia sapporoensis". Planktonic free-living enrichment cultures of these three anammox species were harvested from the membrane bioreactors (MBRs). The physicochemical properties (e.g., contact angle, zeta potential, and surface thermodynamics) were analyzed for these anammox bacterial species and used in the extended DLVO theory to understand the force-distance relationship. In addition, their extracellular polymeric substances (EPSs) were characterized by X-ray photoelectron spectroscopy and nuclear magnetic resonance. The results revealed that the "Ca. B. sinica" cells have the most hydrophobic surface and less hydrophilic functional groups in EPS than other anammox strains, suggesting better aggregation capability. Furthermore, aggregate formation and anammox bacterial populations were monitored when planktonic free-living cells were cultured in up-flow column reactors under the same conditions. Rapid development of microbial aggregates was observed with the anammox bacterial population shifts to a dominance of "Ca. B. sinica" in all three reactors. The dominance of "Ca. B. sinica" could be explained by its better aggregation ability and the superior growth kinetic properties (higher growth rate and affinity to nitrite). The superior aggregation ability of "Ca. B. sinica" indicates significant advantages (efficient and rapid start-up of anammox reactors due to better biomass retention as granules and consequently stable performance) in wastewater treatment application.

Site-specific Chemotherapy Based on Predicted Primary Site by Pathological Profile for Carcinoma of Unknown Primary Site

AIMS

Although platinum-based combination chemotherapies are commonly used for unfavourable subsets of cancer of unknown primary (CUP), the prognosis remains poor. Several studies have suggested that gene expression profiling or immunohistochemistry was useful for the prediction of primary sites in CUP, and site-specific therapy based on predicted primary sites might improve overall outcomes. In Japan, to identify primary sites, immunohistochemical tests were commonly used for CUP in clinical practice. However, it is unclear whether site-specific therapy based on predicted primary sites by pathological examination contributes survival benefit for unfavourable CUP subsets.

PATIENTS AND METHODS

In this study, 122 patients with unfavourable subsets of CUP were retrospectively reviewed. Ninety patients assigned to cohort A after July 2012 had received chemotherapy according to predicted primary sites; 32 patients assigned to cohort B before June 2012 had received platinum-based empiric chemotherapy.

RESULTS

In cohort A, 56 patients (62.2%) with predicted primary sites by pathological examination received site-specific therapy; 34 patients (37.8%) with unpredictable primary sites received platinum-based empiric chemotherapy, the same as cohort B. The median overall survival was 20.3 months in patients with predictable primary sites in cohort A and 10.7 months in those of cohort B, with a significant difference between these cohorts (P = 0.03, adjusted hazard ratio = 0.57, 95% confidence interval 0.34-0.94).

CONCLUSION

Site-specific therapy based on predicted primary sites by pathological examination could improve prognosis in patients with an unfavourable subset of CUP.

Microbial competition among anammox bacteria in nitrite-limited bioreactors

Phylogenetically diverse anammox bacteria have been detected in most of anoxic natural and engineered ecosystems and thus regarded as key players in the global nitrogen cycle. However, ecological niche differentiation of anammox bacteria remains unresolved despite its ecological and practical importance. In this study, the microbial competitions for a common substrate (nitrite) among three anammox species (i.e. "Candidatus Brocadia sinica", "Candidatus Jettenia caeni" and "Candidatus Kuenenia stuttgartiensis") were systematically investigated in nitrite-limited gel-immobilized column reactors (GICR) and membrane bioreactors (MBRs) under different nitrogen loading rates (NLRs). 16 S rRNA gene-based population dynamics revealed that "Ca. J. caeni" could proliferate only at low NLRs, whereas "Ca. B. sinica" outcompeted other two species at higher NLRs in both types of reactors. Furthermore, FISH analysis revealed that "Ca. J. caeni" was mainly present as spherical microclusters at the inner part (low NO₂^- environment), whereas "Ca. B. sinica" was present throughout the gel beads and granules. This spatial distribution supports the outcomes of the competition experiments. However, the successful competition of "Ca. J. caeni" at low NLR could not be explained with the Monod model probably due to inaccuracy of kinetic parameters such as half saturation constant (K_s) for nitrite and a difference in the maintenance rate (m). In addition, the growth of "Ca. K. stuttgartiensis" could not be observed in any experimental conditions, suggesting possible unknown factor(s) is missing. Taken together, NLR was one of factors determining ecological niche differentiation of "Ca. B. sinica" and "Ca. J. caeni".

Maximum specific growth rate of anammox bacteria revisited

Anammox bacteria have long been considered to be slow-growing bacteria. However, it has recently been reported that they could grow much faster than previously thought when they were cultivated in a membrane bioreactor (MBR) with a step-wise decrease in the solid retention time (SRT). Here, we reevaluated the maximum specific growth rates (μ_max) of three phylogenetically distant anammox bacterial species (i.e. "Ca. Brocadia sinica", "Ca. Jettenia caeni" and "Ca. Scalindua sp.") by directly measuring 16S rRNA gene copy numbers using newly developed quantitative polymerase chain reaction (qPCR) assays. When free-living planktonic "Ca. B. sinica" and "Ca. J. caeni" cells were immobilized in polyvinyl alcohol (PVA) and sodium alginate (SA) gel beads and cultivated in an up-flow column reactor with high substrate loading rates at 37 °C, the μ_max were determined to be 0.33 ± 0.02 d^-1 and 0.18 d^-1 (corresponding doubling time of 2.1 day and 3.9 day) from the exponential increases in 16S rRNA genes copy numbers, respectively. These values were faster than the fastest growth rates reported for these species so far. The cultivation of anammox bacteria in gel beads was achieved less than one month without special cultivation method and selection pressure, and the exponential increase in 16S rRNA gene numbers was directly measured by qPCR with high reproducibility; therefore, the resulting μ_max values were considered accurate. Taken together, the fast growth is, therefore, considered to be an intrinsic kinetic property of anammox bacteria.