High-power polycrystalline Er:YAG ceramic laser at 1617 nm

We report on the efficient operation of a high-power erbium-doped polycrystalline Er:YAG ceramic laser at 1617 nm resonantly pumped by a high-power 1532 nm Er,Yb fiber laser. Lasing characteristics of Er:YAG ceramics with different Er3+ concentrations are evaluated and compared. With an output coupler of 15% transmission and 0.5 at. % Er3+-doped YAG ceramic as the gain media, the laser generates 14 W of output power at 1617 nm for 28.8 W of incident pump power at 1532 nm, corresponding to a slope efficiency with respect to incident pump power of 51.7%.

P5-01-18: Identification of Pax6 as a Human Breast Cancer-Testis Antigen

Background

Cancer-testis antigens (CTAs) are specifically expressed in the normal testis and various types of cancer cells, but not or expressed with very low level in the other normal tissues. CTAs are considered to be promising targets for immunotherapy. Little is known on CTAs which specifically expressed in breast cancer. Studies show that the transcriptional activation by CpG island hypomethylation is believed to be an important mechanism of their increased expression.

Objective: To find CTAs which specifically expressed in breast cancer; prove the increase of its expression in human breast cancer, and explore the possibility for it to be developed as target for the immunodiagnosis and immunotherapy of breast cancer.

Methods and results Genomic DNAs were isolated from testis tissue, breast cancer and normal breast tissues respectively. To perform CpG island microarray assays, genomic DNAs were prepared from 15 paired breast cancer biopsies and their normal controls. After obtaining sequence information for those clones from the CpG island database, they were then used to search for surrounding genes in the gene banks. We found several testis specific genes, such as, Pax6, NDRG3 and Synaptojanin 2. Since the last two genes had been extended investigated, they were not the subjects of this study. The Pax6 Gene Was Activated in Established and Primary Breast Cancer Cell Lines. First, we examined Pax6 gene expression levels in a breast cancer cell line panel that included Hs578T, MDA-231, MDA-436, MDA-468, T47D, MCF7 and MCF7/Adr, by performing RT-PCR where b-actin served as control. In addition, the RNAs obtained from normal breast and testis tissues were used as negative and positive controls.We found that Pax6 was re-expressed in MDA-436, MDA-468, T47D, and MCF7/Adr. To further test the Pax6 gene's behavior in primary breast cancer cells, we isolated breast cancer epithelial cells from the effusions of 8 patients (E4, E5, K151, K259, K473, K573, K596 and K605). cRNAs were prepared from those cells and the normal human breast cell line (NHBEC) for RT-PCR assays, where cRNAs of paired MCF7 cells and b-actin served as controls. Results showed that Pax6 was expressed in K259, K573, K596 and K605 cells to various degrees. Pax6 Was Expressed in a Majority of Breast Cancer Biopsies. To test if Pax6 was also expressed in breast cancer tissues, IHC assays were carried out using 19 patients’ biopsies where human testes served as positive controls. We found that the Pax6 protein existed mainly in the cytoplasm of breast cancer cells, but was not detectable in normal breast tissue sections.

Conclusion CpG islands of pax6 promoter region were hypomethylated in human breast cancer. The mRNA level of Pax6 in human breast cancer was significantly increased contrast to normal breast tissue, contrast to all other analyzed normal tissues, suggesting Pax6 is a CTA for breast cancer and might be applied as molecular target in immunotherapy against human breast cancer.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-01-18.

P4-07-12: Identification of p53 Mutation in Whole Genome DNA from Single Circulating Tumor Cells (CTCs) and Primary Breast Cancers (BC) from Patients (pts) with Metastatic Breast Cancer (MBC)

Background: CTCs represent the source of distant metastases, and are also implied in the growth/re-growth of primary BC. Molecular/gene-level characterization of similarities and discordances between CTCs and BCs in pts with MBC may provide useful information for individualized treatment. Since somatic p53 mutations are frequently observed in primary BCs, we set out to assess the feasibility of identifying such mutations in CTCs from pts with MBCs, and compare the findings with those of the primary BCs from the same pts. Material and Method: Fiber-optic Array Scanning Technology (FAST) was used for identification and location of CTCs on large glass substrates. CTCs were identified after blood samples (10 ml) from MBC pts were stained to detect CTCs via automated digital microscopy by morphology, based on immunofuorescence staining for cytokeratin and nucleus, and the absence of CD45. Single CTCs from 10 pts with MBC were identified and removed from the glass substrates. DNA was extracted, and the whole genome of isolated CTCs was amplified by using whole genome amplification method (Sigma). P53 mutations in exon 5, exon 6, exon 7 and exon 8 were assessed. As comparison, genomic DNA from formalin-fixed and paraffin-embedded (FFPE) from primary BCs of the same pts, was amplified using the same method.

Results: p53 mutations were found in 8 out of 10 CTCs, and in 4 out of 10 in primary BC samples. Of 8 mutations detected in CTCs, one silent mutation and 7 missense mutations were seen. One particular point mutation, R181L, previously assessed as functional mutation, was observed in 4 out of 8 CTCs. None of the 4 mutations (a silent mutation, one missense mutation and two different deletions) detected in tumor samples were found in CTCs. We validated that the mutations detected in CTCs were not artifacts occurring during genome amplification, by comparing p53 mutations between unamplified tumor genomic DNA vs. amplified samples.

Conclusion: Whole genome amplification based on extracting DNA from single CTCs using FAST, and identification of mutations such as those in p53, is feasible. The quantitative and qualitative discordance in detecting p53 mutations between CTCs and primary BCs may be due to CTCs acquiring new -possibly epithelial-mesenchymal transition-like-characteristics with metastatic potential as they evolve from the primary tumors or metastatic sites, or, technical issues (analyzing FFPE-preserved vs. CTCs, tumor heterogeneity) may contribute to our findings. Further assessment of the functionality of high frequent functional mutations such as R181L is warranted.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-07-12.

P3-14-21: Neoadjuvant Therapy Response, Subtype and BRCA Status in an Underserved Population

Background

Preoperative (neoadjuvant) chemotherapy is typically used for larger operable breast cancer cases, and the degree of pathological response correlates with long term outcome. Therapeutic response also depends on biological and molecular subtype and is increasingly studied in the research setting to identify prognostic biomarkers and potential therapeutic targets. Little is known about the interactions of neoadjuvant response with biomarker subtypes and genetic predisposition in underserved and minority populations.

Methods: IRB approval was obtained to capture demographic, clinicopathological and genetic testing data on patients diagnosed with invasive breast cancer and treated with preoperative chemotherapy and definitive surgery between 2005 and 2010 at Los Angeles County Medical Center, which serves a primarily Hispanic and indigent population. Treatment followed NCCN guidelines with the exception that not all patients with HER2+ disease received trastuzumab. Genetic counseling and testing has been available at this center since 2007. Pathological complete response (pCR) was defined as no residual invasive disease in breast or nodes. Chi-square or Fisher's Exact test was used to examine associations between pCR and clinical factors, and logistic regression analyses were applied to assess each variable's contribution to pCR.

Results: Among 104 patients, of whom 79% were Hispanic, the overall pCR rate was 27%. Significantly higher pCR rates were seen in age ≥50, clinical N0, HER2+, triple negative, and lumpectomy cases. No differences in pCR rate was seen in Hispanics vs. others, Grade III vs. I and II or in the 9 BRCA mutations carriers among 45 tested compared to no mutation or those not tested. Of the 43 patients with HER2+ disease, the pCR rate was higher in the 32 patients who received trastuzumab (pCR 50.0 vs. 27.3%). Subset pCR rates and odds ratios (OR) of achieving pCR are shown below:

Association between the Interleukin 10-1082G>A polymorphism and coronary heart disease risk in a Caucasian population: a meta-analysis

Interleukin-10 (IL-10) is a cytokine with anti-inflammatory and B-cell-stimulating activity. IL-10 is expressed in human atherosclerotic plaques and studies have shown the involvement of IL-10 in the atherosclerotic process. The IL-10-1082G/A polymorphism is one of the most commonly studied polymorphisms in this gene because of its association with coronary heart disease (CHD) risks, but previous results have been conflicting. We performed a meta-analysis using six eligible case-control studies (including 14 data sets) with a total of 5006 patients and 3968 controls to summarize the existing data on the association between the IL-10-1082G/A polymorphism and CHD risk. Compared with the common IL-10-1082G/A GG genotype, the carriers of variant genotypes (IL-10-1082GA/AA) had a 1.12-fold elevated risk of CHD (95% CI = 1.01-1.23, P = 0.03) under the dominant genetic model, as estimated using a random effect model. The effect of the IL-10-1082G/A polymorphism was further evaluated using stratification analysis. In the three disease of artery studies, with the variant genotypes had a not obvious increased risk of disease of artery (OR = 1.19, 95% CI = 0.98-1.44, P = 0.08) as estimated using a fixed effect model. Similar results were found in the nine myocardial infarction studies (OR = 1.13, 95% CI = 1.00-1.27, P = 0.05). It was also demonstrated that the increased risk of CHD associated with IL-10-1082G/A variant genotypes was more pronounced in Caucasians (OR = 1.12, 95% CI = 1.01-1.23, P = 0.03). Our meta-analysis suggests that the IL-10-1082G/A polymorphism genotypes (GA+AA) might be associated with an increased risk of CHD, especially in Caucasians.

Nocardia infection in kidney transplant recipients: case report and analysis of 66 published cases

Nocardiosis is a rare but life-threatening opportunistic infection, especially in immune compromised patients, including kidney transplant recipients. Primary pulmonary infection is the most common clinical pattern, and can easily result in disseminated Nocardia infection if treatment therapy is not adequate at the beginning. In this article, we report a new case of disseminated nocardiosis (lungs, skin, and pericardium) after renal allograft transplantation. We also review the English literature published from 1980 to 2010 and analyze the clinical characteristics of nocardiosis in kidney transplant recipients.

Serine/threonine protein phosphatase 6 modulates the radiation sensitivity of glioblastoma

Increasing the sensitivity of glioblastoma cells to radiation is a promising approach to improve survival in patients with glioblastoma multiforme (GBM). This study aims to determine if serine/threonine phosphatase (protein phosphatase 6 (PP6)) is a molecular target for GBM radiosensitization treatment. The GBM orthotopic xenograft mice model was used in this study. Our data demonstrated that the protein level of PP6 catalytic subunit (PP6c) was upregulated in the GBM tissue from about 50% patients compared with the surrounding tissue or control tissue. Both the in vitro survival fraction of GBM cells and the patient survival time were highly correlated or inversely correlated with PP6c expression (R²=0.755 and −0.707, respectively). We also found that siRNA knockdown of PP6c reduced DNA-dependent protein kinase (DNA-PK) activity in three different GBM cell lines, increasing their sensitivity to radiation. In the orthotopic mice model, the overexpression of PP6c in GBM U87 cells attenuated the effect of radiation treatment, and reduced the survival time of mice compared with the control mice, while the PP6c knocking-down improved the effect of radiation treatment, and increased the survival time of mice. These findings demonstrate that PP6 regulates the sensitivity of GBM cells to radiation, and suggest small molecules disrupting or inhibiting PP6 association with DNA-PK is a potential radiosensitizer for GBM.

A New Approach to the Detection of Lesions in Mammography Using Fuzzy Clustering

Breast cancer is a leading cause of female mortality and its early detection is an important means of reducing this. The present study investigated an approach, based on fuzzy clustering, to detect small lesions, such as microcalcifications and other masses, that are hard to recognize in breast cancer screening. A total of 180 mammograms were analysed and classified by radiologists into three groups ( n = 60 per group): those with microcalcifications; those with tumours; and those with no lesions. Twenty mammograms were taken as training data sets from each of the groups. The algorithm was then applied to the data not taken for training. Analysis by fuzzy clustering achieved a mean accuracy of 99.7% compared with the radiologists' findings. It was concluded that the fuzzy clustering algorithm allowed for more efficient and accurate detection of breast lesions and may improve the early detection of breast tumours.

Cognitive impairment using education-based cutoff points for CMMSE scores in elderly Chinese people of agricultural and rural Shanghai China

OBJECTIVES

To evaluate cognitive impairment (CI) in rural China using the Chinese version of the Mini-Mental Status Examination (CMMSE) and compare the prevalence of CI using two different cutoff points.

MATERIALS & METHODS

A population-based survey was conducted of 2809 people aged 60 years and above in a community of two towns (Huaxin and Xujing) in the Qingpu district, located in the western suburb of Shanghai. Face-to-face interviews were carried out to collect relevant information with questionnaires. The Chinese version of the Mini-Mental State Examination with either a 23/24 cutoff point or a cutoff point varying according to education level (AEL) was used to screen subjects for CI.

RESULTS

Among these subjects, the mean age was 70.6 years (SD = 6.6) and ranged from 60 to 92 years and included 1010 (36.0%) men and 1799 (64.0%) women. The mean age was 70.7 years (SD = 6.4) for men and 70.5 years (SD = 6.7) for women. Of the 2809 subjects, 2010 (71.5%) had no formal education, 607 (21.6%) completed 1-6 years of education, and 173 (6.2%) completed more than 6 years of school education. The prevalence of CI was 35.6% (95% CI: 33.8-37.4) for both genders when the cutoff point of 23/24 was used. However, when the cutoff point was altered with respect to different education levels, the prevalence of CI was 7.0%. For each item of the CMMSE, increased years of education correlated with a higher item score, with the exception of the 'Naming' item score.

CONCLUSIONS

This study demonstrates that screening of CI using the AEL cutoff scores is feasible in a low-education population. Determining whether the 23/24 cutoff point is suitable for the Chinese people requires future prospective studies in a large Chinese population.

A novel correction factor based on extended volume to complement the conformity index

OBJECTIVE

We propose a modified conformity index (MCI), based on extended volume, that improves on existing indices by correcting for the insensitivity of previous conformity indices to reference dose shape to assess the quality of high-precision radiation therapy and present an evaluation of its application.

METHODS

In this paper, the MCI is similar to the conformity index suggested by Paddick (CI(Paddick)), but with a different correction factor. It is shown for three cases: with an extended target volume, with an extended reference dose volume and without an extended volume. Extended volume is generated by expanding the original volume by 0.1-1.1 cm isotropically. Focusing on the simulation model, measurements of MCI employ a sphere target and three types of reference doses: a sphere, an ellipsoid and a cube. We can constrain the potential advantage of the new index by comparing MCI with CI(Paddick). The measurements of MCI in head-neck cancers treated with intensity-modulated radiation therapy and volumetric-modulated arc therapy provide a window on its clinical practice.

RESULTS

The results of MCI for a simulation model and clinical practice are presented and the measurements are corrected for limited spatial resolution. The three types of MCI agree with each other, and comparisons between the MCI and CI(Paddick) are also provided.

CONCLUSION

The results from our analysis show that the proposed MCI can provide more objective and accurate conformity measurement for high-precision radiation therapy. In combination with a dose-volume histogram, it will be a more useful conformity index.

Chemical characterization and in vitro fermentation ofBrassicastraw treated with the aerobic fungus,Trametes versicolor

Ramirez-Bribiesca, J. E., Wang, Y., Jin, L., Canam, T., Town, J. R., Tsang, A., Dumonceaux, T. J. and McAllister, T. A. 2011. Chemical characterization and in vitro fermentation of Brassica straw treated with the aerobic fungus, Trametes versicolor . Can. J. Anim. Sci. 91: 695–702. Brassica napus straw (BNS) was either not treated or was treated with two strains of Trametes versicolor; 52J (wild type) or m4D (a cellobiose dehydrogenase-deficient mutant) with four treatments: (i) untreated control (C-BNS), (ii) 52J (B-52J), (iii) m4D (B-m4D) or (iv) m4D+glucose (B-m4Dg). Glucose was provided to encourage growth of the mutant strain. All treatments with T. versicolor decreased (P<0.05) neutral-detergent fibre and increased (P<0.05) protein and the concentration of lignin degradation products in straw. Ergosterol was highest (P<0.05) in straw treated with B-52J, suggesting it generated the most fungal biomass. Insoluble lignin was reduced (P<0.05) in straw treated with B-52J and B-m4D, but not with B-m4Dg. Mannose and xylose concentration were generally higher (P<0.05) in straw treated with fungi, whereas glucose and galactose were lower as compared with C-BNS. The four treatments above were subsequently assessed in rumen in vitro fermentations, along with BNS treated with 2 mL g−1of 5 N NaOH. Concentrations of total volatile fatty acids after 24 and 48h were lower (P<0.05) in incubations that contained BNS treated with T. versicolor as compared with C-BNSor NaOH-treated BNS. Compared with C-BNS, in vitrodry matter disappearance and gas production were increased (P<0.05) by NaOH, but not by treatment with either strain of T. versicolor. Although treatment with T. versicolor did release more lignin degradation products, it did not appear to provide more degradable carbohydrate to in vitro rumen microbial populations, even when a mutant strain with compromised carbohydrate metabolism was utilized. Production of secondary compounds by the aerobic fungi may inhibit rumen microbial fermentation.

Cerebrospinal Fluid Levels of Soluble Amyloid Precursor Protein and β-Amyloid 42 in Patients with Multiple Sclerosis, Neuromyelitis Optica and Clinically Isolated Syndrome

Amyloid precursor protein (APP) accumulation in axonal ovoids is a sensitive marker for acute axonal injury in multiple sclerosis (MS) lesions. This study measured levels of α-cleaved soluble APP (αsAPP) and β-amyloid 42 (Aβ42) in the cerebrospinal fluid (CSF) of 42 MS, 10 neuromyelitis optica and 25 clinically isolated syndrome patients and 21 healthy controls, and analysed the correlation between αsAPP and Aβ42 levels and relevant clinical parameters. The CSF concentrations of αsAPP and Aβ42 in patients and controls were not significantly different. There was a significant inverse correlation in patients between CSF asAPP concentration and the Expanded Disability Status Scale (EDSS), but no significant correlation between CSF Aβ42 concentration and EDSS. The concentration of αsAPP in the CSF of statin-treated patients was significantly higher than in those not treated with statins, suggesting that statins may have a neuroprotective effect. In conclusion, αsAPP was present at similar levels in the CSF of patients with neuromyelitis optica, MS and clinically isolated syndrome and healthy controls, and an inverse correlation existed between CSF αsAPP concentration and neurological disability.

Contribution of visceral fat accumulation to carotid intima-media thickness in a Chinese population

Objective:

Recent observational studies have reported that body fat distribution might be differentially associated with subclinical atherosclerosis. We previously reported that visceral fat area (VFA) ⩾80 cm² is the optimal cutoff for identifying abdominal obesity in Chinese subjects. We examined whether VFA ⩾80 cm² reflects the association between abdominal obesity and subclinical atherosclerosis, and if determination of the visceral fat quantity is useful for assessing subclinical atherosclerosis in asymptomatic individuals.

Methods and results:

Participants (N=1005, men 515, women 490, 34–66 years) free of cardiovascular disease underwent magnetic resonance imaging and carotid ultrasound assessment to quantify VFA and carotid intima–media thickness (C-IMT). Overweight/obese subjects (body mass index (BMI) ⩾25.0 kg m⁻²) had a higher C-IMT than lean subjects (BMI <25.0 kg m⁻²) (P<0.01). Subjects with VFA ⩾80 cm² had significantly higher C-IMT than those without abdominal obesity regardless of BMI (P<0.01). By multivariate regression analysis adjusted for anthropometric measurements and cardiovascular risk factors, waist circumference but not BMI was independently correlated with C-IMT in men (P<0.001). Similar findings were observed with an accurate obesity indices adjusted model, which showed that VFA was an independent risk factor for increased C-IMT in men but not in women.

Conclusions:

VFA ⩾80 cm² effectively identified carotid atherosclerosis for both lean and obese individuals in middle-aged Chinese men.

Coherent magnetic plasmon modes in a contacting gold nano-sphere chain on a gold slab

A coupled magnetic resonator waveguide, composed of a contacting gold nanosphere chain on a gold slab, is proposed and investigated. A broadband coherent magnetic plasmon mode can be excited in this one dimensional nanostructure. By employing the Lagrangian formalism and the Fourier transform method, the dispersion properties of the wave vector and group velocity of the magnetic plasmon mode are investigated. Small group velocity can be obtained from this system which can be applied as subwavelength slow wave waveguides.

Intrarenal metabolomics reveals the association of local organic toxins with the progression of diabetic kidney disease

The pathological development of diabetic kidney disease (DKD) might involve metabolic perturbations in kidney tissue. The present study was designed to detect the systematic alterations of renal cortex metabolites thereby exploring the related mechanisms of DKD development and fosinopril treatment. Based on combined gas chromatography/time-of-flight mass spectrometry (GC-TOF MS) and liquid chromatography/time-of-flight mass spectrometry (UPLC-TOF MS) data acquiring platform, we have performed a metabolomic analysis of perfused renal cortex samples from the diabetic rats induced by streptozocin and treated with or without fosinopril, a pharmacological inhibitor of angiotensin II converting enzyme (ACEI). We identified a number of abnormal metabolites in the diabetic kidney, including groups of amino acids, carbohydrates, polyols, lyso-phospholipids, glucuronides and other unidentified metabolites. Of them, an increase in intrarenal organic toxins including uremic toxins, glucuronides and glucotocixity-associated metabolites are highly correlated with diabetic kidney injury including 24h urinary protein levels and tubulointerstitial injury index. Treatment with fosinopril significantly attenuated diabetic kidney injury, and simultaneously blocked the intrarenal accumulation of these organic toxins, especially hippurate and glucuronides. These results indicate that intrarenal accumulation of organic toxins may be significant for the development of DKD and the related mechanisms deserve to be further investigated.

The incidence and risk factors of invasive fungal infection after haploidentical haematopoietic stem cell transplantation without in vitro T-cell depletion

In recent years, we have successfully established a novel method of haploidentical haematopoietic stem cell transplantation (HSCT) without in vitro T-cell depletion. This study was aimed at analysing the incidence and risk factors of invasive fungal infection (IFI) with this transplantation method. The study comprised 291 patients who had undergone haploidentical HSCT from 1 January 2007 to 31 December 2008. IFI was diagnosed according to the European Organization for Research and Treatment of Cancer/Mycoses Study Group 2002 criteria, and only proven or probable cases of IFI were regarded as true cases. A total of 39 patients were documented as having IFI, including four proven cases and 35 probable cases. The median time of diagnosis was 26 days (range: 6-405 days) after transplantation. The cumulative incidence rates of IFI at 40 days, 1 year, 2 years and 3 years after transplantation were 8.25%, 13.1%, 13.4% and 13.4%, respectively. Multivariate analysis identified platelet engraftment time (>17 days) (p 0.027; hazard ratio (HR) 2.432; 95% CI 1.105-5.355), a high risk of underlying disease (p 0.001; HR 2.916; 95% CI 1.515-5.611) and grade III-IV acute graft-versus-host disease (p 0.019; HR 2.407; 95% CI 1.154-5.022) as risk factors for IFI. The incidence rates of IFI in patients with no, one, two or three risk factors at 3 years after transplantation were 4.48%, 7.86%, 29.6% and 23.1%, respectively. In conclusion, IFI is an important complication following haploidentical HSCT without in vitro T-cell depletion.

Effect of radiotherapy after breast-conserving surgery on 10-year recurrence and 15-year breast cancer death: meta-analysis of individual patient data for 10,801 women in 17 randomised trials

BACKGROUND

After breast-conserving surgery, radiotherapy reduces recurrence and breast cancer death, but it may do so more for some groups of women than for others. We describe the absolute magnitude of these reductions according to various prognostic and other patient characteristics, and relate the absolute reduction in 15-year risk of breast cancer death to the absolute reduction in 10-year recurrence risk.

METHODS

We undertook a meta-analysis of individual patient data for 10,801 women in 17 randomised trials of radiotherapy versus no radiotherapy after breast-conserving surgery, 8337 of whom had pathologically confirmed node-negative (pN0) or node-positive (pN+) disease.

FINDINGS

Overall, radiotherapy reduced the 10-year risk of any (ie, locoregional or distant) first recurrence from 35·0% to 19·3% (absolute reduction 15·7%, 95% CI 13·7-17·7, 2p<0·00001) and reduced the 15-year risk of breast cancer death from 25·2% to 21·4% (absolute reduction 3·8%, 1·6-6·0, 2p=0·00005). In women with pN0 disease (n=7287), radiotherapy reduced these risks from 31·0% to 15·6% (absolute recurrence reduction 15·4%, 13·2-17·6, 2p<0·00001) and from 20·5% to 17·2% (absolute mortality reduction 3·3%, 0·8-5·8, 2p=0·005), respectively. In these women with pN0 disease, the absolute recurrence reduction varied according to age, grade, oestrogen-receptor status, tamoxifen use, and extent of surgery, and these characteristics were used to predict large (≥20%), intermediate (10-19%), or lower (<10%) absolute reductions in the 10-year recurrence risk. Absolute reductions in 15-year risk of breast cancer death in these three prediction categories were 7·8% (95% CI 3·1-12·5), 1·1% (-2·0 to 4·2), and 0·1% (-7·5 to 7·7) respectively (trend in absolute mortality reduction 2p=0·03). In the few women with pN+ disease (n=1050), radiotherapy reduced the 10-year recurrence risk from 63·7% to 42·5% (absolute reduction 21·2%, 95% CI 14·5-27·9, 2p<0·00001) and the 15-year risk of breast cancer death from 51·3% to 42·8% (absolute reduction 8·5%, 1·8-15·2, 2p=0·01). Overall, about one breast cancer death was avoided by year 15 for every four recurrences avoided by year 10, and the mortality reduction did not differ significantly from this overall relationship in any of the three prediction categories for pN0 disease or for pN+ disease.

INTERPRETATION

After breast-conserving surgery, radiotherapy to the conserved breast halves the rate at which the disease recurs and reduces the breast cancer death rate by about a sixth. These proportional benefits vary little between different groups of women. By contrast, the absolute benefits from radiotherapy vary substantially according to the characteristics of the patient and they can be predicted at the time when treatment decisions need to be made.

FUNDING

Cancer Research UK, British Heart Foundation, and UK Medical Research Council.