Shape Evolution in Neutron-Rich Krypton Isotopes Beyond N=60: First Spectroscopy of ^{98,100}Kr

We report on the first γ-ray spectroscopy of low-lying states in neutron-rich ^{98,100}Kr isotopes obtained from ^{99,101}Rb(p,2p) reactions at ∼220  MeV/nucleon. A reduction of the 2_{1}^{+} state energies beyond N=60 demonstrates a significant increase of deformation, shifted in neutron number compared to the sharper transition observed in strontium and zirconium isotopes. State-of-the-art beyond-mean-field calculations using the Gogny D1S interaction predict level energies in good agreement with experimental results. The identification of a low-lying (0_{2}^{+}, 2_{2}^{+}) state in ^{98}Kr provides the first experimental evidence of a competing configuration at low energy in neutron-rich krypton isotopes consistent with the oblate-prolate shape coexistence picture suggested by theory.

Shell Evolution towards ^{78}Ni: Low-Lying States in ^{77}Cu

The level structure of the neutron-rich ^{77}Cu nucleus is investigated through β-delayed γ-ray spectroscopy at the Radioactive Isotope Beam Factory of the RIKEN Nishina Center. Ions of ^{77}Ni are produced by in-flight fission, separated and identified in the BigRIPS fragment separator, and implanted in the WAS3ABi silicon detector array, surrounded by Ge cluster detectors of the EURICA array. A large number of excited states in ^{77}Cu are identified for the first time by correlating γ rays with the β decay of ^{77}Ni, and a level scheme is constructed by utilizing their coincidence relationships. The good agreement between large-scale Monte Carlo shell model calculations and experimental results allows for the evaluation of the single-particle structure near ^{78}Ni and suggests a single-particle nature for both the 5/2_{1}^{-} and 3/2_{1}^{-} states in ^{77}Cu, leading to doubly magic ^{78}Ni.

Gamma Decay of Unbound Neutron-Hole States in ^{133}Sn

Excited states in the nucleus ^{133}Sn, with one neutron outside the double magic ^{132}Sn core, were populated following one-neutron knockout from a ^{134}Sn beam on a carbon target at relativistic energies at the Radioactive Isotope Beam Factory at RIKEN. Besides the γ rays emitted in the decay of the known neutron single-particle states in ^{133}Sn additional γ strength in the energy range 3.5-5.5 MeV was observed for the first time. Since the neutron-separation energy of ^{133}Sn is low, S_{n}=2.402(4)  MeV, this observation provides direct evidence for the radiative decay of neutron-unbound states in this nucleus. The ability of electromagnetic decay to compete successfully with neutron emission at energies as high as 3 MeV above threshold is attributed to a mismatch between the wave functions of the initial and final states in the latter case. These findings suggest that in the region southeast of ^{132}Sn nuclear structure effects may play a significant role in the neutron versus γ competition in the decay of unbound states. As a consequence, the common neglect of such effects in the evaluation of the neutron-emission probabilities in calculations of global β-decay properties for astrophysical simulations may have to be reconsidered.

94 β-Decay Half-Lives of Neutron-Rich _{55}Cs to _{67}Ho: Experimental Feedback and Evaluation of the r-Process Rare-Earth Peak Formation

The β-decay half-lives of 94 neutron-rich nuclei ^{144-151}Cs, ^{146-154}Ba, ^{148-156}La, ^{150-158}Ce, ^{153-160}Pr, ^{156-162}Nd, ^{159-163}Pm, ^{160-166}Sm, ^{161-168}Eu, ^{165-170}Gd, ^{166-172}Tb, ^{169-173}Dy, ^{172-175}Ho, and two isomeric states ^{174m}Er, ^{172m}Dy were measured at the Radioactive Isotope Beam Factory, providing a new experimental basis to test theoretical models. Strikingly large drops of β-decay half-lives are observed at neutron-number N=97 for _{58}Ce, _{59}Pr, _{60}Nd, and _{62}Sm, and N=105 for _{63}Eu, _{64}Gd, _{65}Tb, and _{66}Dy. Features in the data mirror the interplay between pairing effects and microscopic structure. r-process network calculations performed for a range of mass models and astrophysical conditions show that the 57 half-lives measured for the first time play an important role in shaping the abundance pattern of rare-earth elements in the solar system.

Review of chemotherapeutic approaches for operable and inoperable esophageal squamous cell carcinoma

The predominant histological types of esophageal cancer are adenocarcinoma and squamous cell carcinoma. Since these two histological types present as different diseases in terms of their epidemiology, pathologenesis, and tumor biology, separate therapeutic approaches should be developed against each type. While surgical resection remains the dominant therapeutic intervention for patients with operable esophageal squamous cell carcinoma (ESCC), their high rates of tumor recurrence have prompted investigation of multimodality therapies that combine surgery with chemotherapy, radiotherapy, and chemoradiotherapy. In Japan, preoperative chemotherapy with cisplatin (CDDP) plus 5-fluorouracil (5-FU) followed by radical esophagectomy has been accepted as the standard therapeutic approach for resactable clinical Stage II/III ESCC. Similarly, the CDDP and 5-FU regimen has been accepted as the first-line treatment for metastatic and unresectable ESCCs in Japan. Thus, in Japan chemotherapy is an indispensable component of therapy for both resectable and unresectable ESCCs. This review discusses the current knowledge, rationale, and available data regarding chemotherapy for resectable and unresectable ESCCs.

Long-term outcomes of radiofrequency ablation combined with hepatectomy compared with hepatectomy alone for colorectal liver metastases

Background

Combining radiofrequency ablation (RFA) with hepatectomy may enable treatment with curative intent for patients with colorectal liver metastasis (CRLM). However, the oncological outcomes in comparison with resection alone remain to be clarified.

Methods

Patients who underwent a first hepatectomy between 2001 and 2012 for CRLM were enrolled. Short- and long-term outcomes of patients who underwent hepatectomy plus RFA were compared with those of patients who had hepatectomy alone using propensity score matching.

Results

Of a total of 553 patients, hepatectomy + RFA and hepatectomy alone were performed in 37 and 516 respectively. Before matching, patients in the hepatectomy + RFA group were characterized primarily by a larger tumour burden. After matching of 31 patients who underwent hepatectomy + RFA with 93 who had hepatectomy alone, background characteristics were well balanced. In the matched cohort, overall and disease-free survival in the hepatectomy + RFA group were no different from those among patients who had hepatectomy alone (5-year overall survival rate 57 versus 61 per cent, P = 0·649; 5-year disease-free survival rate 19 versus 17 per cent, P = 0·865). Local recurrence at the ablated site was observed in four of 31 patients (13 per cent). Although overall local recurrence (ablated site and/or cut surface) was more frequent in the hepatectomy + RFA group (9 of 31 (29 per cent) versus 11 of 93 (12 per cent); P = 0·032), there was no difference in intrahepatic disease-free survival between the two groups (P = 0·705).

Conclusion

Hepatectomy + RFA achieved outcomes comparable to hepatectomy alone. Combining RFA with hepatectomy should be considered as an option to achieve cure.

Are There Signatures of Harmonic Oscillator Shells Far from Stability? First Spectroscopy of ^{110}Zr

The first measurement of the low-lying states of the neutron-rich ^{110}Zr and ^{112}Mo was performed via in-beam γ-ray spectroscopy after one proton removal on hydrogen at ∼200  MeV/nucleon. The 2_{1}^{+} excitation energies were found at 185(11) keV in ^{110}Zr, and 235(7) keV in ^{112}Mo, while the R_{42}=E(4_{1}^{+})/E(2_{1}^{+}) ratios are 3.1(2), close to the rigid rotor value, and 2.7(1), respectively. These results are compared to modern energy density functional based configuration mixing models using Gogny and Skyrme effective interactions. We conclude that first levels of ^{110}Zr exhibit a rotational behavior, in agreement with previous observations of lighter zirconium isotopes as well as with the most advanced Monte Carlo shell model predictions. The data, therefore, do not support a harmonic oscillator shell stabilization scenario at Z=40 and N=70. The present data also invalidate predictions for a tetrahedral ground state symmetry in ^{110}Zr.

Applying a PCR-based open-reading frame typing method for easy genotyping and molecular epidemiological analysis of Pseudomonas aeruginosa

AIMS

Molecular epidemiological techniques, such as pulsed-field gel electrophoresis (PFGE), or multilocus sequence typing (MLST) have facilitated our understanding of the transmission routes of nosocomial infections by Pseudomonas aeruginosa. However, they are time consuming and technically demanding. To perform molecular epidemiological analysis in a standard microbiology laboratory, we aimed to develop a simpler and effective molecular epidemiological technique based on the open-reading frame (ORF) distribution patterns detected by PCR, which we call PCR-based ORF typing (POT).

METHODS AND RESULTS

Ten ORFs from genomic islets, five ORFs from genomic islands, and the metallo-β-lactamases (MBLs) blaIMP and blaVIM were selected by comparing the whole-genome sequences of different Ps. aeruginosa strains (PAO1, PA7, UCBPP-PA14 and LESB58). These 17 ORFs were detected, along with a Ps. aeruginosa marker, using 9-plex and 10-plex PCR systems. The genotypes in the POT were compared to those obtained by using PFGE and MLST.

CONCLUSIONS

Using the POT method, molecular epidemiological analyses of Ps. aeruginosa can be completed in 4 h.

SIGNIFICANCE AND IMPACT OF THE STUDY

Since this method is very easy to perform, even in standard clinical laboratories, it could be a valuable tool for monitoring daily infection control measures.

Clinical features and treatment of patients with esophageal cancer and a history of gastrectomy: a multicenter, questionnaire survey in Kyushu, Japan

It is still controversial whether patients with a history of gastrectomy have high risk of esophageal carcinogenesis. On the other hand, the treatment strategy for esophageal cancer patients after gastrectomy is complicated. The association between histories of gastrectomy and esophageal carcinogenesis was retrospectively analyzed, and the treatment of esophageal cancer patients after gastrectomy was evaluated based on questionnaire data collected from multiple centers in Kyushu, Japan. The initial subject population comprised 205 esophageal cancer patients after gastrectomy. Among them, 108 patients underwent curative surgical treatment, and 70 patients underwent chemoradiation therapy (CRT). The time between gastrectomy and esophageal cancer development was longer in peptic ulcer patients (28.3 years) than in gastric cancer patients (9.6 years). There were no differences in the location of esophageal cancer according to the gastrectomy reconstruction method. There were no significant differences in the clinical background characteristics between patients with and without a history of gastrectomy. Among the 108 patients in the surgery group, the 5-year overall survival rates for stages I (n = 30), II (n = 18), and III (n = 60) were 68.2%, 62.9%, and 32.1%, respectively. In the CRT group, the 5-year overall survival rate of stage I (n = 29) was 82.6%, but there were no 5-year survivors in other stages. The 5-year overall survival rate of patients with CR (n = 33) or salvage surgery (n = 10) was 61.2% or 36%, respectively. For the treatment of gastrectomized esophageal cancer patients, surgery or CRT is recommended for stage I, and surgery with or without adjuvant therapy is the main central treatment in advanced stages, with surgery for stage II, neoadjuvant therapy + surgery for stage III, and CRT + salvage surgery for any stage, if the patient's condition permits.

Serum Levels of Albumin-β-Amyloid Complex in Patients with Depression

OBJECTIVE

Epidemiologic studies have demonstrated that suffering from depression may be a risk for Alzheimer disease (AD). As a possible biologic mechanism underlying the transition from depression to AD, it has been speculated that pathologic changes in β-amyloid (Aβ) metabolism are involved. To further understand the peripheral kinetics of amyloid in patients with depression, we investigated serum levels of free Aβ and albumin-bound Aβ.

METHODS

Seventy inpatients with DSM-IV major depressive disorder (MDD) and 81 healthy individuals (the comparison group) were recruited between June 2012 and February 2014. Serum Aβ40 and Aβ42 levels, Aβ40/Aβ42 ratio, and serum levels of albumin-Aβ complexes (SLAACs) were compared between the comparison group and patients in two age groups comprising younger (<60 years) and elderly (≥60 years) people.

RESULTS

SLAAC was decreased in older patients with MDD but not in younger patients. The serum-free Aβ40/Aβ42 ratio was higher in patients with depression, even in younger patients.

CONCLUSION

Our findings suggest that free Aβ and the albumin-bound Aβ reflect a different serum amyloid kinetics in depression. We speculate that serum-free Aβ reflects changes in amyloid metabolism in patients suffering from depression and albumin-bound Aβ reflects AD pathology and may be a potential predictor of the prodromal stage of AD.

Outcome after associating liver partition and portal vein ligation for staged hepatectomy and conventional two-stage hepatectomy for colorectal liver metastases

BACKGROUND

Although associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) has been increasingly adopted by many centres, the oncological outcome for colorectal liver metastases compared with that after two-stage hepatectomy is still unknown.

METHODS

Between January 2010 and June 2014, all consecutive patients who underwent either ALPPS or two-stage hepatectomy for colorectal liver metastases in a single institution were included in the study. Morbidity, mortality, disease recurrence and survival were compared.

RESULTS

The two groups were comparable in terms of clinicopathological characteristics. ALPPS was completed in all 17 patients, whereas the second-stage hepatectomy could not be completed in 15 of 41 patients. Ninety-day mortality rates for ALPPS and two-stage resection were 0 per cent (0 of 17) versus 5 per cent (2 of 41) (P = 0·891). Major complication rates (Clavien grade at least III) were 41 per cent (7 of 17) and 39 per cent (16 of 41) respectively (P = 0·999). Overall survival was significantly lower after ALPPS than after two-stage hepatectomy: 2-year survival 42 versus 77 per cent respectively (P = 0·006). Recurrent disease was more often seen in the liver in the ALPPS group. Salvage surgery was less often performed after ALPPS (2 of 8 patients) than after two-stage hepatectomy (10 of 17).

CONCLUSION

Although major complication and 90-day mortality rates of ALPPS were similar to those of two-stage hepatectomy, overall survival was significantly lower following ALPPS.

Prognostic and clinical impact of sarcopenia in esophageal squamous cell carcinoma

Recently, depletion of skeletal muscle mass (sarcopenia) has been linked to poor prognosis in several types of cancers, but has not been investigated in esophageal squamous cell carcinoma (ESCC). This retrospective study investigates the relationship between sarcopenia and clinical outcome in ESCC patients treated by surgical resection or definitive chemoradiation therapy (dCRT). The study was retrospectively conducted in a single academic hospital in Kumamoto, Japan, and involved 325 ESCC patients (256 surgical cases and 69 dCRT cases) treated between April 2005 and April 2011. Skeletal muscle mass was quantified by radiologic measures using standard computed tomography scans. The skeletal muscle tissue in the 325 ESCC patients was distributed as follows: mean: 47.10; median: 46.88; standard deviation (SD): 7.39; range: 31.48-71.11; interquartile range, 46.29-47.90. Skeletal muscle tissue was greater in male patients than in female patients (P < 0.0001), but was independent of other clinical and tumor features. Sarcopenia was not significantly associated with overall survival (log rank P = 0.54). Lymph node involvement significantly altered the relationship between sarcopenia and survival rate (P for interaction = 0.026). Sarcopenia significantly reduced the overall survival of patients without lymph node involvement (log rank P = 0.035), but was uncorrelated with overall survival in patients with lymph involvement (log rank, P = 0.31). The anastomosis leakage rate was significantly higher in the sarcopenia group than in the non-sarcopenia group (P = 0.032), but other surgical complications did not significantly differ between the two groups. Sarcopenia in ESCC patients without lymph node involvement is associated with poor prognosis, indicating sarcopenia as a potential biomarker for identifying patients likely to experience an inferior outcome. Moreover, sarcopenia was associated with anastomosis leakage but no other short-term surgical outcome.

[Depression and Bipolar Disorder: Risk Factors and Potential Prevention of Developing Dementia]

Epidemiological studies have demonstrated that suffering from depression and bipolar disorder may be risk factors for developing dementia. A mechanism of interactions of several factors, such as vascular disease and glucocorticoid, has been speculated to play a role in the development of dementia. It is suggested that the onset of dementia can be prevented or delayed by preventing the onset and recurrence of depression and bipolar disorder. In the prevent of depression, the management of daily life, such as diet and exercise, is important. Recently, the possibility of preventive effects of antidepressants and lithium on developing dementia has been suggested, and a future intervention study is expected.

Long-term outcome of esophagectomy for primary malignant melanoma of the esophagus: a single-institute retrospective analysis

Primary malignant melanoma of the esophagus (PMME) is a highly malignant tumor with a poor prognosis. Because PMME is an extremely rare disease, therapeutic strategies against the tumor have yet to be established, and the efficacy of esophagectomy remains unclear. The objective of this study was to evaluate the post-esophagectomy survival of PMME patients. Ten patients who underwent esophagectomy for PMME between March 2005 and April 2013 at the Department of Gastroenterological Surgery, Cancer Institute Hospital, Tokyo, Japan, were identified from the institutional database. We retrospectively retrieved clinical information and data on the long-term outcomes from the patients' records. Survival rates after esophagectomy were calculated by the Kaplan-Meier method, and the hazard ratios of mortality were determined using the Cox's model. A follow-up study of the 10 patients revealed 7 cancer recurrences and 5 deaths. Median survival time was 34.5 months, and 5 of 10 patients survived longer than 2 years. The 1-year disease-free survival rate was 40%, and the 1- and 3-year overall survival rates were 70% and 60%, respectively. Importantly, all three of the non-relapsing patients were histologically confirmed as free of lymph node involvement. The four patients with lymph node metastasis relapsed within 1 year. The disease-free survival was significantly shorter in patients with lymph node involvement than in those without lymph node involvement (univariate hazard ratio = 13.3, 95% confidence interval 1.85-266.4; P = 0.009). In conclusion, esophagectomy might benefit PMME patients with no lymph node metastasis. Further large-scale cohort studies are needed to establish the treatment strategy for PMME.

New Isotopes and Proton Emitters-Crossing the Drip Line in the Vicinity of ^{100}Sn

Several new isotopes, ^{96}In, ^{94}Cd, ^{92}Ag, and ^{90}Pd, have been identified at the RIKEN Nishina Center. The study of proton drip-line nuclei in the vicinity of ^{100}Sn led to the discovery of new proton emitters ^{93}Ag and ^{89}Rh with half-lives in the submicrosecond range. The systematics of the half-lives of odd-Z nuclei with T_{z}=-1/2 toward ^{99}Sn shows a stabilizing effect of the Z=50 shell closure. Production cross sections for nuclei in the vicinity of ^{100}Sn measured at different energies and target thicknesses were compared to the cross sections calculated by epax taking into account contributions of secondary reactions in the primary target.

A randomized phase III trial comparing S-1 versus UFT as adjuvant chemotherapy for stage II/III rectal cancer (JFMC35-C1: ACTS-RC)

This phase III study is the first study to demonstrate the superiority of new oral fluoropyrimidine S-1 over tegafur–uracil as adjuvant chemotherapy for stage II/III rectal cancer patients with no preoperative treatment in terms of relapse-free survival. S-1 can be considered an important option, especially for patients who have not received preoperative treatment.

Backgrounds

Preventing distant recurrence and achieving local control are important challenges in rectal cancer treatment, and use of adjuvant chemotherapy has been studied. However, no phase III study comparing adjuvant chemotherapy regimens for rectal cancer has demonstrated superiority of a specific regimen. We therefore conducted a phase III study to evaluate the superiority of S-1 to tegafur–uracil (UFT), a standard adjuvant chemotherapy regimen for curatively resected stage II/III rectal cancer in Japan, in the adjuvant setting for rectal cancer.

Patients and methods

The ACTS-RC trial was an open-label, randomized, phase III superiority trial conducted at 222 sites in Japan. Patients aged 20–80 with stage II/III rectal cancer undergoing curative surgery without preoperative therapy were randomly assigned to receive UFT (500–600 mg/day on days 1–5, followed by 2 days rest) or S-1 (80–120 mg/day on days 1–28, followed by 14 days rest) for 1 year. The primary end point was relapse-free survival (RFS), and the secondary end points were overall survival and adverse events.

Results

In total, 961 patients were enrolled from April 2006 to March 2009. The primary analysis was conducted in 480 assigned to receive UFT and 479 assigned to receive S-1. Five-year RFS was 61.7% [95% confidence interval (CI) 57.1% to 65.9%] for UFT and 66.4% (95% CI 61.9% to 70.5%) for S-1 [P = 0.0165, hazard ratio (HR): 0.77, 95% CI 0.63–0.96]. Five-year survival was 80.2% (95% CI 76.3% to 83.5%) for UFT and 82.0% (95% CI 78.3% to 85.2%) for S-1. The main grade 3 or higher adverse events were increased alanine aminotransferase and diarrhea (each 2.3%) in the UFT arm and anorexia, diarrhea (each 2.6%), and fatigue (2.1%) in the S-1 arm.

Conclusion

One-year S-1 treatment is superior to UFT with respect to RFS and has therefore become a standard adjuvant chemotherapy regimen for stage II/III rectal cancer following curative resection.

Nucleus ^{26}O: A Barely Unbound System beyond the Drip Line

The unbound nucleus ^{26}O has been investigated using invariant-mass spectroscopy following one-proton removal reaction from a ^{27}F beam at 201  MeV/nucleon. The decay products, ^{24}O and two neutrons, were detected in coincidence using the newly commissioned SAMURAI spectrometer at the RIKEN Radioactive Isotope Beam Factory. The ^{26}O ground-state resonance was found to lie only 18±3(stat)±4(syst)  keV above threshold. In addition, a higher lying level, which is most likely the first 2^{+} state, was observed for the first time at 1.28_{-0.08}^{+0.11}  MeV above threshold. Comparison with theoretical predictions suggests that three-nucleon forces, pf-shell intruder configurations, and the continuum are key elements to understanding the structure of the most neutron-rich oxygen isotopes beyond the drip line.

Candidate Resonant Tetraneutron State Populated by the ^{4}He(^{8}He,^{8}Be) Reaction

A candidate resonant tetraneutron state is found in the missing-mass spectrum obtained in the double-charge-exchange reaction ^{4}He(^{8}He,^{8}Be) at 186  MeV/u. The energy of the state is 0.83±0.65(stat)±1.25(syst)  MeV above the threshold of four-neutron decay with a significance level of 4.9σ. Utilizing the large positive Q value of the (^{8}He,^{8}Be) reaction, an almost recoilless condition of the four-neutron system was achieved so as to obtain a weakly interacting four-neutron system efficiently.

Residual memory impairment in remitted depression may be a predictive factor for recurrence

OBJECTIVE

Memory impairment in remitted depression is reported to be related to the number of previous depressive episodes. A recent report hypothesized that each depressive episode increases the risk of memory impairment during remission, which further increases the risk of recurrence. We investigated whether the risk for recurrence increased as a function of memory impairment at remission.

METHOD

One hundred ten participants with DSM-IV-TR major depressive disorder (MDD) after remission (defined as a score ≤ 7 on the Hamilton Depression Rating Scale) were recruited between April 2004 and March 2012 and were followed up prospectively. All patients were divided into 2 groups: those who had memory impairment and those who had no memory impairment after remission. (Memory impairment was determined with the Wechsler Memory Scale-Revised.) The time to recurrence of depression (a score ≥ 4 on the Clinical Global Impressions-Severity of Illness scale) was compared between the groups prospectively. Kaplan-Meier survival curves, log-rank test for trend for survivor functions, and Cox proportional hazard ratio (HR) estimates for a multivariate model were conducted to examine the risk of recurrence by presence of memory impairment after remission.

RESULTS

One hundred nine participants completed this study. In the follow-up period, recurrence occurred in 25 (55.6%) of the 45 patients with memory impairment and 21 (32.8%) of the 64 patients with no memory impairment. In the Kaplan-Meier survival estimates for time to incidence of recurrence in patients with and without memory impairment, the cumulative probability of developing a recurrence for patients with memory impairment was higher than for patients with no memory impairment (log-rank test: χ(2)1 = 4.63, P = .03). Survival analysis was also performed using Cox proportional hazards regression in a multivariate model. The presence of memory impairment remained significantly associated with incidence of recurrence (HR = 2.55; 95% CI, 1.30-4.99; P = .006).

CONCLUSIONS

The presence of residual memory impairment in patients with remitted MDD may increase the risk of recurrence.

Nomogram for prediction of prognosis in patients with initially unresectable colorectal liver metastases

BACKGROUND

Although recent advances in surgery and chemotherapy have increasingly enabled hepatectomy in patients with initially unresectable colorectal liver metastases (CRLM), not all such patients benefit from surgery. The aim of this study was to develop a nomogram to predict survival after hepatectomy for initially unresectable CRLM.

METHODS

Patients with initially unresectable CRLM treated with chemotherapy followed by hepatectomy between 1990 and 2012 were included in the study. A nomogram to predict survival was developed based on a multivariable Cox model. The predictive performance of the model was assessed according to the C-statistic, Kaplan-Meier curve and calibration plots.

RESULTS

Of a total of 439 patients, liver and globally completed surgery was achieved in 380 (86·6 per cent) and 335 (76·3 per cent) patients respectively. The 5-year overall and disease-free survival rates were 39·9 and 10·0 per cent respectively. Based on the Cox model, the following five factors were selected for the nomogram and assigned specific scores: node-positive primary, 5; more than six metastases at hepatectomy, 7; carbohydrate antigen 19-9 level at hepatectomy above 37 units/ml, 10; disease progression during first-line chemotherapy, 9; and presence of extrahepatic disease, 4. The model achieved relatively good discrimination and calibration, with a C-statistic of 0·66. The overall survival rate for patients with a score greater than 16 was significantly worse than that for patients with a score of 16 or less (5-year survival rate 4 versus 46·3 per cent respectively; P < 0·001).

CONCLUSION

The nomogram facilitates personalized assessment of prognosis for patients with initially unresectable CRLM treated with chemotherapy and with planned resection.

A randomized phase II study of S-1 plus oral leucovorin versus S-1 monotherapy in patients with gemcitabine-refractory advanced pancreatic cancer

This is the first phase II trial in which adding oral leucovorin (LV) to S-1 (SL) significantly prolonged progression-free survival (PFS) when compared with S-1 monotherapy (S) in patients with gemcitabine-refractory advanced pancreatic cancer (PC). The significantly better PFS and disease control rate with SL than with S suggest that the antitumor activity of S-1 is enhanced by LV in advanced PC.

Background

We evaluated the efficacy and toxicity of adding oral leucovorin (LV) to S-1 when compared with S-1 monotherapy in patients with gemcitabine-refractory pancreatic cancer (PC).

Patients and methods

Gemcitabine-refractory PC patients were randomly assigned in a 1:1 ratio to receive S-1 at 40, 50, or 60 mg according to body surface area plus LV 25 mg, both given orally twice daily for 1 week, repeated every 2 weeks (SL group), or S-1 monotherapy at the same dose as the SL group for 4 weeks, repeated every 6 weeks (S-1 group). The primary end point was progression-free survival (PFS).

Results

Among 142 patients enrolled, 140 were eligible for efficacy assessment (SL: n = 69 and S-1: n = 71). PFS was significantly longer in the SL group than in the S-1 group [median PFS, 3.8 versus 2.7 months; hazard ratio (HR), 0.56; 95% confidence interval (CI), 0.37–0.85; P = 0.003]). The disease control rate was significantly higher in the SL group than in the S-1 group (91% versus 72%; P = 0.004). Overall survival (OS) was similar in both groups (median OS, 6.3 versus 6.1 months; HR, 0.82; 95% CI, 0.54–1.22; P = 0.463). After adjusting for patient background factors in a multivariate analysis, OS tended to be better in the SL group (HR, 0.71; 95% CI, 0.47–1.07; P = 0.099). Both treatments were well tolerated, although gastrointestinal toxicities were slightly more severe in the SL group.

Conclusion

The addition of LV to S-1 significantly improved PFS in patients with gemcitabine-refractory advanced PC, and a phase III trial has been initiated in a similar setting.

Clinical trials number

Japan Pharmaceutical Information Center: JapicCTI-111554.