Proton Shell Gaps in N=28 Nuclei from the First Complete Spectroscopy Study with FRIB Decay Station Initiator

The first complete measurement of the β-decay strength distribution of _{17}^{45}Cl_{28} was performed at the Facility for Rare Isotope Beams (FRIB) with the FRIB Decay Station Initiator during the second FRIB experiment. The measurement involved the detection of neutrons and γ rays in two focal planes of the FRIB Decay Station Initiator in a single experiment for the first time. This enabled an analytical consistency in extracting the β-decay strength distribution over the large range of excitation energies, including neutron unbound states. We observe a rapid increase in the β-decay strength distribution above the neutron separation energy in _{18}^{45}Ar_{27}. This was interpreted to be caused by the transitioning of neutrons into protons excited across the Z=20 shell gap. The SDPF-MU interaction with reduced shell gap best reproduced the data. The measurement demonstrates a new approach that is sensitive to the proton shell gap in neutron rich nuclei according to SDPF-MU calculations.

Observation of New Isotopes in the Fragmentation of ^{198}Pt at FRIB

Five previously unknown isotopes (^{182,183}Tm, ^{186,187}Yb, ^{190}Lu) were produced, separated, and identified for the first time at the Facility for Rare Isotope Beams (FRIB) using the Advanced Rare Isotope Separator (ARIS). The new isotopes were formed through the interaction of a ^{198}Pt beam with a carbon target at an energy of 186  MeV/u and with a primary beam power of 1.5 kW. Event-by-event particle identification of A, Z, and q for the reaction products was performed by combining measurements of the energy loss, time of flight, magnetic rigidity Bρ, and total kinetic energy. The ARIS separator has a novel two-stage design with high resolving power to strongly suppress contaminant beams. This successful new isotope search was performed less than one year after FRIB operations began and demonstrates the discovery potential of the facility which will ultimately provide 400 kW of primary beam power.

Discovery of ^{39}Na

The new isotope ^{39}Na, the most neutron-rich sodium nucleus observed so far, was discovered at the RIKEN Nishina Center Radioactive Isotope Beam Factory using the projectile fragmentation of an intense ^{48}Ca beam at 345  MeV/nucleon on a beryllium target. Projectile fragments were separated and identified in flight with the large-acceptance two-stage separator BigRIPS. Nine ^{39}Na events have been unambiguously observed in this work and clearly establish the particle stability of ^{39}Na. Furthermore, the lack of observation of ^{35,36}Ne isotopes in this experiment significantly improves the overall confidence that ^{34}Ne is the neutron dripline nucleus of neon. These results provide new key information to understand nuclear binding and nuclear structure under extremely neutron-rich conditions. The newly established stability of ^{39}Na has a significant impact on nuclear models and theories predicting the neutron dripline and also provides a key to understanding the nuclear shell property of ^{39}Na at the neutron number N=28, which is normally a magic number.

Location of the Neutron Dripline at Fluorine and Neon

A search for the heaviest isotopes of fluorine, neon, and sodium was conducted by fragmentation of an intense ^{48}Ca beam at 345  MeV/nucleon with a 20-mm-thick beryllium target and identification of isotopes in the large-acceptance separator BigRIPS at the RIKEN Radioactive Isotope Beam Factory. No events were observed for ^{32,33}F, ^{35,36}Ne, and ^{38}Na and only one event for ^{39}Na after extensive running. Comparison with predicted yields excludes the existence of bound states of these unobserved isotopes with high confidence levels. The present work indicates that ^{31}F and ^{34}Ne are the heaviest bound isotopes of fluorine and neon, respectively. The neutron dripline has thus been experimentally confirmed up to neon for the first time since ^{24}O was confirmed to be the dripline nucleus nearly 20 years ago. These data provide new keys to understanding the nuclear stability at extremely neutron-rich conditions.

Discovery of ^{60}Ca and Implications For the Stability of ^{70}Ca

The discovery of the important neutron-rich nucleus _{20}^{60}Ca_{40} and seven others near the limits of nuclear stability is reported from the fragmentation of a 345  MeV/u ^{70}Zn projectile beam on ^{9}Be targets at the radioactive ion-beam factory of the RIKEN Nishina Center. The produced fragments were analyzed and unambiguously identified using the BigRIPS two-stage in-flight separator. The eight new neutron-rich nuclei discovered, ^{47}P, ^{49}S, ^{52}Cl, ^{54}Ar, ^{57}K, ^{59,60}Ca, and ^{62}Sc, are the most neutron-rich isotopes of the respective elements. In addition, one event consistent with ^{59}K was registered. The results are compared with the drip lines predicted by a variety of mass models and it is found that the models in best agreement with the observed limits of existence in the explored region tend to predict the even-mass Ca isotopes to be bound out to at least ^{70}Ca.

A Q-TWiST analysis comparing panitumumab plus best supportive care (BSC) with BSC alone in patients with wild-type KRAS metastatic colorectal cancer

Background:

Panitumumab+best supportive care (BSC) significantly improved progression-free survival (PFS) vs BSC alone in patients with chemo-refractory wild-type KRAS metastatic colorectal cancer (mCRC). We applied the quality-adjusted time without symptoms of disease or toxicity (Q-TWiST) analysis to provide an integrated measure of clinical benefit, with the objective of comparing quality-adjusted survival between the two arms. As the trial design allowed patients on BSC alone to receive panitumumab after disease progression, which confounded overall survival (OS), the focus of this analysis was on PFS.

Methods:

For each treatment group, the time spent in the toxicity (grade 3 or 4 adverse events; TOX), time without symptoms of disease or toxicity (TWiST), and relapse (after disease progression; REL) states were estimated by the product-limit method, and adjusted using utility weights derived from patient-reported EuroQoL 5-dimensions measures. Sensitivity analyses were performed in which utility weights (varying from 0 to 1) were applied to time in the TOX and REL health states.

Results:

There was a significant difference between groups favouring panitumumab+BSC in quality-adjusted PFS (12.3 weeks vs 5.8 weeks, respectively, P<0.0001) and quality-adjusted OS (P=0.0303).

Conclusion:

In patients with chemo-refractory wild-type KRAS mCRC, panitumumab+BSC significantly improved quality-adjusted survival compared with BSC alone.

Impact of lapatinib monotherapy on QOL and pain symptoms in patients with HER2+ relapsed or refractory inflammatory breast cancer

OBJECTIVE

EGF103009 (ClinicalTrials.gov identifier: NCT00105950) was a phase 2, open-label, multicenter study that showed lapatinib monotherapy to be clinically active in women with relapsed or refractory HER2+ (ErbB2+) inflammatory breast cancer that progressed following prior therapy with anthracyclines, taxanes, and trastuzumab. The objective of the present study was to assess the impact of lapatinib on quality of life (QOL) and pain symptoms in these patients.

RESEARCH DESIGN AND METHODS

QOL and pain assessments were added during a study amendment and hence only 33 of 126 HER2+ patients were available for baseline assessment. QOL and pain were assessed using the EORTC QLQ-C30 and Brief Pain Inventory-Short Form (BPI-SF) questionnaires, respectively. Both questionnaires were completed at baseline and every 4 weeks thereafter. Change from baseline in QOL and pain scores were summarized by visit. In a post hoc analysis, scores were compared between patients with different clinical response status.

RESULTS

Over 60% of the 33 HER2+ patients with the baseline assessments completed the first three postbaseline assessments (week 4, n = 26; week 8, n = 21; week 12, n = 20). At week 8, improvement from baseline in mean EORTC QLQ-C30 scores was observed for global QOL (delta = 14.5; 95% CI: 4.0, 25.0), role functioning (delta = 15; 95% CI: 0.9, 29.1), social functioning (delta = 14.9; 95% CI: -0.5, 30.3), and physical functioning subscales (delta = 9.0; 95% CI: 1.2, 16.8). All symptom scales (except diarrhea) improved from baseline at most scheduled visits during the 20-week follow-up period. Mean scores for all four BPI-SF summary pain scores at week 8 suggested improvement in pain severity and pain interference. Clinical responders had improved scores on most aspects of QOL, compared with declining scores among nonresponders to treatment.

CONCLUSIONS

The QOL improvement among the small number of patients with QOL data indicates that lapatinib monotherapy may improve level of functioning/QOL and provide relief from symptoms, including pain, in the short term. These QOL benefits add to the clinical improvement associated with lapatinib therapy in heavily pretreated patients with an aggressive form of breast cancer.

First-line treatment with lapatinib plus paclitaxel versus paclitaxel alone for patients with HER2+ metastatic breast cancer (MBC): Quality-of-life (QOL) analysis using repeated measures and pattern mixture models

1049

Background: A phase III randomized, multicenter, double-blind, placebo-controlled study compared first-line therapy with lapatinib and paclitaxel (L+P) versus paclitaxel alone (P) for MBC. In a sub-group analysis of HER2+ patients, time to tumor progression for L+P was significantly improved, with an emerging trend for survival benefit. This analysis models the QOL data in the subset of the randomized ITT population that overexpressed HER2 (FISH+ or IHC3+). Methods: QOL was assessed using the Functional Assessment of Cancer Therapy-Breast (FACT-B) questionnaire. Outcome measures included FACT-B total score, trial outcome index (TOI) score and breast cancer subscale (BCS). Higher scores represent better QOL. Patients completed the FACT-B at the screening visit, week 9, every 12 weeks thereafter, and at discontinuation of therapy. The assessment at discontinuation was applied to the next scheduled visit for analyses. Changes from baseline were analyzed using repeated measures models with baseline score as a covariate. Pattern mixture modeling was implemented as a sensitivity analysis. Results: Of 579 randomized patients, 86 were HER-2+ and 85 completed at least one item from the FACT-B (n = 48 L+P; n = 37 P). The baseline characteristics of this subset were well-matched with regard to age, ECOG status, and prior anthracycline use. More patients in the L+P group than in the P group had visceral disease (69% vs 51%) and more were at stage IV (88% vs 78%).Over the first year, the L+P arm demonstrated stable FACT-B scores over time, whereas average scores for patients on paclitaxel monotherapy decreased (change from baseline: L+P p = 0.99; P p = 0.01). Statistically significant differences were observed between treatment arms on the FACT-B (p = 0.05), TOI (p = 0.03), and BCS (p = 0.01). Pattern mixture models suggested more QOL differentiation between treatments among patients who progressed or withdrew within 6 months of study start. Conclusions: Among patients with HER2+ MBC, treatment with L+P resulted in more stable QOL than with P monotherapy. These findings represent clinically important differences between treatment groups.

[Table: see text]

Relationship between survival and estrogen receptor (ER) status in pts with metastatic breast cancer (MBC) treated with capecitabine (C) and docetaxel (D): An exploratory data analysis

1024

Background: Previous studies in pts with MBC have shown that women with ER+ tumors have a longer survival time compared to women with ER- tumors. An exploratory analysis was conducted to describe the relationship between survival and ER status among MBC pts treated with combination therapy consisting of C+D. Methods: This analysis used data from an open-label, randomized phase III trial of C+D vs D alone in pts with advanced and/or MBC. Survival analysis was used to investigate the effect of baseline ER status of the primary and metastatic tumors on overall survival (OS). ER status was defined as positive if positive for any tumor, negative if at least 1 negative test, otherwise unknown. Results: Among 506 intent-to-treat pts (randomized, received ≥1 dose), ER status was identified in 356. C+D: 90 ER+, 88 ER-; D alone: 95 ER+, 83 ER-. The unadjusted log-rank test showed a significant difference in OS between the C+D and D groups for ER+ but not ER- pts. In the ER+ group, median OS was longer in C+D vs D pts (538.5 vs 379.0 d) (hazard ratio [HR] 0.65; P=0.007). OS was significantly longer in ER+ vs ER- pts in the C+D group (538.5 vs 329.0 d) (HR 0.68; P=0.019) but not in the D group (379.0 vs 301.0 d) (HR 0.90; P=0.514). OS by time from diagnosis to recurrence and baseline tumor size showed no significant differences between ER+ and ER- pts. Conclusions: This exploratory analysis suggested a significant difference in OS between the C + D and D groups in ER+ (HR 0.65) but not ER- (HR 0.90) pts. Also, within the C+D group, the median OS was significantly longer in ER+ than ER- pts (HR 0.68).

[Table: see text]

[Table: see text]

Lapatinib plus letrozole compared with letrozole alone as first-line therapy in hormone receptor positive HER2+ metastatic breast cancer (MBC): A quality-of-life (QOL) analysis

1039

Background: A phase III randomized double-blind multicenter trial compared lapatinib plus letrozole (L+Let) with letrozole plus placebo (Let), as first-line therapy for hormone receptor positive (HR+) MBC. Median PFS, the primary endpoint of the study, in patients who were HER2+ was significantly prolonged for L+Let compared with Let (8.2 vs 3 months, Hazard Ratio (95% CI)=0.71(0.53,0.96), p=0.019). This analysis focuses on the impact of treatments on QOL in the HER2+ subgroup. Methods: QOL outcomes included the Functional Assessment of Cancer Therapy-Breast (FACT-B) total, FACT-general (FACT-G), and trial outcome index (TOI) scores assessed at screening, every 12 weeks and at withdrawal. Higher scores indicate better QOL. Changes from baseline were analyzed using analysis of covariance. In a responder analysis, patients achieving minimally important differences in QOL scores (QOL responders) were compared with Fisher's exact test. Results: Among 1,286 patients, 219 were identified as HER2+ (L+Let n=111; Let n=108). Baseline QOL scores were comparable in the two arms. In this population, mean changes in subscale and total QOL scores were generally stable over time in both treatment arms for patients who stayed on study. For example, on the FACT-B, the average change from baseline in both groups was positive at all scheduled visits through Week 48 and the maximum difference between arms was 2.6 points (CI: -5.8, 11). There were no significant differences between the two treatment arms in percentage of QOL responders (Table). Conclusions: The addition of lapatinib to letrozole significantly increases PFS while maintaining QOL when compared with letrozole alone thus confirming the clinical benefit of the combination therapy in the HR+, HER2+ MBC patient population. This combination provides an effective option in this patient population by maintaining QOL and delaying the need for chemotherapy and its accompanying side effects.

[Table: see text]

[Table: see text]

The effect of age on overall survival (OS) in patients with metastatic breast cancer (MBC) treated with capecitabine

1097

Background: Both in monotherapy and in combination with a taxane, C has been shown to improve OS in patients with MBC. Since C is often used in older adults because of tolerability and ease of administration (PO vs IV), and lack of alopecia, an exploratory analysis was conducted to see if an association exists between age and OS among patients with MBC treated with C. Methods: Data from the intermittent dose (2510 mg/m2) 2 wks on/1 wk off arms of 5 phase II/III monotherapy or combination therapy with C registration trials involving patients with MBC were analyzed. Intent-to-treat (ITT) was defined as all randomized patients who took at least 1 dose of study medication. Patients were divided into 3 groups by age. A Kaplan-Meier method was used to estimate the age-category specific survival by trial. Next, Cox proportional hazard regression analysis was conducted using pooled data from the 5 trials with stratification by trial and key baseline characteristics. Analyses were conducted at the 95% confidence level. Results: A total of 570 ITT patients were included in the analysis (median age 55.0 years; range, 26–83): 193 (34%) were 18–49 years old; 246 (43%) 50–64 years old; and 131 (23%) ≥65 years old. A baseline Karnofsky score ≥90 was observed in 65.3%, 56.5%, and 50.4% of patients, respectively. The median treatment duration (range) was 93.0 (2–397) days in the 18 to 49-year-old group, 109.5 (2–448) days in the 50 to 64-year-old group, and 80.0 (5–371) days in the ≥65-year-old group. Unadjusted log-rank tests for each of the 5 trials showed no significant differences in OS between age categories. In the pooled analysis, Cox regression did not detect significant differences in survival based on age. Using age ≥65 years as the reference group, the hazard ratios were 1.06 (95% CI 0.81, 1.41) for age 18–49 years and 0.99 (95% CI 0.77, 1.29) for age 50–64 years. The Cox model revealed consistent results after further controlling for the Karnofsky score and number of metastatic sites. Conclusions: No statistically significant effect of age on OS was observed in patients with MBC treated with C. OS outcomes appear comparable across predefined age groups of patients with MBC treated with C.

[Table: see text]

Evidence for a change in the nuclear mass surface with the discovery of the most neutron-rich nuclei with 17<or=Z<or=25

The results of measurements of the production of neutron-rich nuclei by the fragmentation of a 76Ge beam are presented. The cross sections were measured for a large range of nuclei including 15 new isotopes that are the most neutron-rich nuclides of the elements chlorine to manganese (50Cl, 53Ar, ;{55,56}K, ;{57,58}Ca, ;{59,60,61}Sc, ;{62,63}Ti, ;{65,66}V, 68Cr, 70Mn). The enhanced cross sections of several new nuclei relative to a simple thermal evaporation framework, previously shown to describe similar production cross sections, indicates that nuclei in the region around 62Ti might be more stable than predicted by current mass models and could be an indication of a new island of inversion similar to that centered on 31Na.

A quality-adjusted time without symptoms or toxicity (Q-TWiST) analysis comparing lapatinib plus paclitaxel versus paclitaxel alone for first line metastatic breast cancer (MBC) in HER2+ patients

Abstract #4090

Background: Women with MBC received first line treatment with lapatinib and paclitaxel (L+P) or paclitaxel alone (P) in a phase III randomized, multicenter, double-blind, placebo-controlled study. In a sub-group analysis of HER2+ (ErbB2+) patients, time to tumor progression for L+P was significantly improved, with an emerging trend for survival benefit. The Q-TWiST method was used to examine overall quality-of-life adjusted survival experience comparing the trade-off between treatment toxicities and delayed progression in a subset of the randomized ITT population that overexpressed HER2.&#x2028; Methods: Survival curves for each treatment arm were partitioned into 3 health states: TOX (toxicity) - time with grade 3/4 adverse events (AEs) during progression-free survival time; TWiST (time without toxicity or disease progression) - remaining time prior to progression in which no serious AEs were experienced; REL (relapse) - time until death or end of follow-up following disease progression. The utility-weighted sum of the mean health state durations was derived to calculate a Q-TWiST score and treatment comparisons were made at varying combinations of the utility weights using a threshold utility analysis.&#x2028; Results: The ITT population included 579 subjects ages 23-87 of which 91 were HER2+ (n = 52 L+P, n = 39 P) based on FISH+ or IHC3+ irrespective of FISH (86 patients based on FISH+ or IHC3+ if FISH unknown; n = 49 L+P, n = 37 P). Overall median survival was 96 weeks after randomization based on data through 5FEB07. For the 91 patient cohort, using utility weights of 0.5 for both TOX and REL, i.e. counting 2 days of TOX or REL as 1 day of TWiST, resulted in a 9.4 week difference (p = 0.0459) in quality-adjusted survival favoring L+P. For the 86 patient cohort the difference was 8.5 weeks still favoring L+P (p = 0.1005). Q-TWiST differences between the arms (for 91 patient cohort) ranged from 5-13 weeks across utility weight combinations, with most tests providing a statistically significant advantage of L+P over P alone. Results from the sensitivity analysis using all grade AEs in the TOX state gave similar results.&#x2028; Conclusions: Among HER2+ patients, treatment with L+P resulted in more quality-adjusted survival than with P monotherapy. When utilities for periods of toxicity and relapse were valued at half the utility of TWiST, the Q-TWIST difference was around 9 weeks, approximately 10% of the 96 weeks median overall survival. These findings represent clinically important differences between treatment groups in quality-adjusted survival.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4090.

Q-TWiST analysis of lapatinib combined with capecitabine for the treatment of metastatic breast cancer

The addition of lapatinib (Tykerb/Tyverb) to capecitabine (Xeloda) delays disease progression more effectively than capecitabine monotherapy in women with previously treated HER2+ metastatic breast cancer (MBC). The quality-adjusted time without symptoms of disease or toxicity of treatment (Q-TWiST) method was used to compare treatments. The area under survival curves was partitioned into health states: toxicity (TOX), time without symptoms of disease progression or toxicity (TWiST), and relapse period until death or end of follow-up (REL). Average times spent in each state, weighted by utility, were derived and comparisons of Q-TWiST between groups performed with varying combinations of the utility weights. Utility weights of 0.5 for both TOX and REL, that is, counting 2 days of TOX or REL as 1 day of TWiST, resulted in a 7-week difference in quality-adjusted survival favouring combination therapy (P=0.0013). The Q-TWiST difference is clinically meaningful and was statistically significant across an entire matrix of possible utility weights. Results were robust in sensitivity analyses. An analysis with utilities based on EQ-5D scores was consistent with the above findings. Combination therapy of lapatinib with capecitabine resulted in greater quality-adjusted survival than capecitabine monotherapy in trastuzumab-refractory MBC patients.

A quality-adjusted time without symptoms or toxicity (Q-TWiST) analysis comparing lapatinib plus capecitabine compared to capecitabine for metastatic breast cancer (MBC)

1026

Background: Data for this analysis is from a Phase III randomized study that was stopped early by the IDMC since a planned interim analysis demonstrated the primary endpoint had been achieved i.e. longer time to disease progression for patients taking lapatinib plus capecitabine (L+C) versus capecitabine (C) alone. The study included women with refractory advanced or ErbB2+ MBC who had received prior therapy which included anthracyclines, taxanes and trastumuzab. The Q-TWiST method was used to compare the trade-off between toxicities and delayed progression. Methods: The area under overall survival curves for each treatment group was partitioned into three health states: toxicity (TOX), time without toxicity or disease progression (TWiST), and the period until death or end of follow-up following disease progression (REL). TOX is time spent with grade ¾ adverse events (AEs) during progression-free survival (PFS) time. TWiST is the remaining time prior to progression in which no serious AEs were experienced. The utility-weighted sum of the mean health state durations was derived and treatment comparisons of Q-TWiST were made at varying combinations of the utility weights using a threshold utility analysis. Results: The ITT population included 399 subjects ages 26–83 [L+C group N=198, C group N=201]. Overall median survival was 67 weeks based on data through 3APR2006. There was not a significant difference between groups in mean duration of serious AEs prior to progression. (L+C 1.7 weeks, C 1.5 weeks). Using utility weights of 0.5 for both TOX and REL, i.e. counting 2 days of TOX or REL as 1 day of TWiST, resulted in a 7-week difference in quality-adjusted survival favoring L+C (p = 0.0013). The Q-TWiST difference was significant across an entire matrix of possible utility weights. Results were robust in sensitivity analyses including all AEs. An observed-utility analysis based on EQ-5D scores is in progress. Conclusions: The longer time to disease progression with L+C versus C was achieved without increased time with serious AEs, resulting in more quality-adjusted survival for patients.

No significant financial relationships to disclose.

Meta-analysis of trials comparing ximelagatran with low molecular weight heparin for prevention of venous thromboembolism after major orthopaedic surgery

Background

Use of low molecular weight heparin (LMWH) is standard practice for preventing postoperative venous thromboembolism (VTE). Ximelagatran is a new direct thrombin inhibitor for this indication.

Methods

A systematic review was conducted to compare the efficacy and safety of LMWH with ximelagatran in orthopaedic surgery.

Results

Six eligible, well conducted clinical trials (10 051 patients) were identified. Overall, the risk of VTE (OR (odds ratio) 1·22 (95 per cent confidence interval (c.i.) 0·89 to 1·67)) and serious bleeding (OR 0·70 (95 per cent c.i. 0·42 to 1·18)) was not significantly different for LMWH compared with ximelagatran. Exploratory analyses to investigate statistical heterogeneity found that results varied by surgical subtype and treatment regimen. Compared with postoperative ximelagatran, LMWH had a significantly lower rate of VTE (OR 0·68 (95 per cent c.i. 0·56 to 0·82); P &lt; 0·001), with no significant difference in bleeding rate (OR 1·09 (95 per cent c.i. 0·62 to 1·94); P = 0·76), in hip surgery, and no significant differences in knee surgery. When ximelagatran was started immediately before surgery, LMWH had a significantly higher rate of VTE in both hip (OR 1·87 (95 per cent c.i. 1·20 to 2·92); P = 0·006) and knee (OR 1·49 (95 per cent c.i. 1·14 to 1·93); P = 0·003) surgery, but less bleeding: hip OR 0·30 (95 per cent c.i. 0·17 to 0·53; P &lt; 0·001); knee OR 0·71 (95 per cent c.i. 0·30 to 1·67; P = 0·43).

Conclusion

This review demonstrated no overall advantage for either LMWH or ximelagatran in thromboprophylaxis following orthopaedic surgery. Benefits in VTE prevention with ximelagatran were gained at the expense of an increased risk of serious bleeding.

Quality-adjusted survival in a crossover trial of letrozole versus tamoxifen in postmenopausal women with advanced breast cancer

BACKGROUND

Results from a phase III study of postmenopausal women with advanced breast cancer demonstrated longer time to disease progression for patients taking letrozole versus tamoxifen. This analysis compares the trade-offs between progression-free survival and toxicity.

DESIGN

Quality-adjusted survival was calculated using Q-TWiST (quality-adjusted time without symptoms or toxicity). Survival curves were partitioned into three health states: toxicity (TOX), disease progression (PROG) and periods without toxicity or disease progression (TWiST). The utility-weighted sum of the health state durations was derived and compared.

RESULTS

There was not a significant difference in mean duration of serious adverse events prior to progression between the letrozole (n=453) and tamoxifen (n=454) groups (2.2 and 2 months, respectively). For TWiST, the mean duration for letrozole was 11.5 months, versus 8.5 months for tamoxifen (P <0.001). The mean duration of PROG was 11.5 months for letrozole and 12.7 months for tamoxifen (P=0.047). Using utility weights of 0.5 for TOX and PROG resulted in a 2.5-month difference in quality-adjusted survival favoring letrozole (P <0.0001).

CONCLUSIONS

The longer time to disease progression with letrozole versus tamoxifen was achieved without increased time with adverse events and resulted in more quality-adjusted survival for patients on letrozole.

Reduced occupancy of the deeply bound 0d(5/2) neutron state in 32Ar

The 9Be(32Ar, 31Ar)X reaction, leading to the 5/2+ ground state of a nucleus at the proton drip line, has a cross section of 10.4(13) mb at a beam energy of 65.1 MeV/nucleon. This translates into a spectroscopic factor that is only 24(3)% of that predicted by the many-body shell-model theory. We introduce refinements to the eikonal reaction theory used to extract the spectroscopic factor to clarify that this very strong reduction represents an effect of nuclear structure. We suggest that it reflects correlation effects linked to the high neutron separation energy (22.0 MeV) for this state.

New approach for measuring properties of rp-process nuclei

A new experimental approach was developed that can reduce the uncertainties in astrophysical rapid proton capture (rp) process calculations due to nuclear data. This approach utilizes neutron removal from a radioactive ion beam to populate the nuclear states of interest. Excited states were deduced by the gamma-decay spectra measured in a semiconductor Ge-detector array. In the first case studied, 33Ar, excited states were measured with uncertainties of several keV. The 2 orders of magnitude improvement in the uncertainty of the level energies resulted in a 3 orders of magnitude improvement in the uncertainty of the calculated 32Cl(p,gamma)33Ar rate that is critical to the modeling of the rp process. This approach has the potential to measure key properties of almost all interesting nuclei on the rp-process path.

New direct reaction: two-proton knockout from neutron-rich nuclei

The reaction 9Be(28Mg,26Ne+gamma)X has been studied at 82 MeV/nucleon together with two similar cases, 30Mg and 34Si. Strong evidence that the reactions are direct is offered by the parallel-momentum distributions of the reaction residues and by the inclusive cross sections. The pattern of the partial cross sections for 28Mg suggests the presence of correlations. A preliminary theoretical discussion based on eikonal reaction theory and the many-body shell model is presented. The reaction holds great promise for the study of neutron-rich nuclei.

S17(0) determined from the Coulomb breakup of 83 MeV /nucleon 8B

A kinematically complete measurement was made of the Coulomb dissociation of 8B nuclei on a Pb target at 83 MeV/nucleon. The cross section was measured at low relative energies in order to infer the astrophysical S factor for the 7Be(p,gamma)8B reaction. A first-order perturbation theory analysis including E1, E2, and M1 transitions was employed to extract the E1 strength relevant to neutrino-producing reactions in the solar interior. By fitting the measured cross section from E(rel) = 130 to 400 keV, we find S17(0) = 17.8(+1.4)(-1.2) eV b.

Direct evidence for the breakdown of the N = 8 shell closure in 12Be

Partial cross sections and corresponding momentum distributions have been studied in the one-neutron knockout reaction ( 12Be,11Be+gamma) on a 9Be target at 78 MeV/nucleon. The resulting spectroscopic factors for the only two bound states of 11Be are 0.42+/-0.06 ( 1/2(+)) and 0.37+/-0.06 ( 1/2(-)), where the errors are experimental only. This result shows that N = 8 is not a good closed shell in the neutron-rich 12Be and that the last neutron pair is two-thirds in the ( 1s(2)+0d(2)) intruder configuration.

One-neutron knockout from individual single-particle states of 11Be

The structure of the halo nucleus 11Be has been studied using the reaction 9Be(11Be,10Be+gamma)X at 60 MeV/nucleon. The ground state structure of 11Be is determined by comparing the experimental cross sections to a calculation combining spectroscopic factors from the shell model with l-dependent single-particle cross sections obtained in an eikonal model. This experiment shows the dominant 1s single-particle character of the 11Be ground state and indicates a small contribution of 0d admixture in the wave function. After correction for the approximately 22% intensity to excited levels, a clean and precise distribution of parallel momentum for knockout from the 1s halo wave function is obtained for the first time.