Global trends in psycho-oncology research investments 2016-2020: A content analysis.

OBJECTIVE: An estimated one-third of cancer patients experience a clinically significant psychological disorder, however it is unclear to what extent this is reflected in research funding. To address this a systematic analysis the allocation of psycho-oncology research funding globally between 2016 and 2020 was conducted. METHODS: A global dataset of 66,388 cancer research awards, from 2016 to 2020 inclusive and totalling $24.5 billion USD was assembled from public and philanthropic funders. Each award was previously categorised by cancer site type and research theme, including psychosocial research and these awards were further sub-categorised for this analysis. RESULTS: There was $523m of funding awarded for psychological research across 1122 studies: 2.14% of all cancer research funding during this period ($24.5 billion). Median funding per award was $97,473 (IQR $36,864 - $453,051). Within psychological research, mental health received most funding ($174m, 33.5% of psychological funding). Cognitive behavioural therapy (CBT) focused research was the specific psychological support with the highest proportion of funding at $14 million. By country of funder, the USA provided most investment ($375.5 m, 71.8%). CONCLUSIONS: Psycho-oncology research received relatively little funding, for example, when compared with pre-clinical cancer research. There needs to be a shift from pre-clinical science to research that benefits cancer patients in the shorter-term. Low- and middle-income countries, and ethnic minorities in higher-income settings, were underrepresented despite having a large cancer burden, indicating inequities that need to be addressed.

Global funding for cancer research between 2016 and 2020: a content analysis of public and philanthropic investments.

BACKGROUND: Cancer is a leading cause of disease burden globally, with more than 19·3 million cases and 10 million deaths recorded in 2020. Research is crucial to understanding the determinants of cancer and the effects of interventions, and to improving outcomes. We aimed to analyse global patterns of public and philanthropic investment in cancer research. METHODS: In this content analysis, we searched the UberResearch Dimensions database and Cancer Research UK data for human cancer research funding awards from public and philanthropic funders between Jan 1, 2016, and Dec 31, 2020. Included award types were project and programme grants, fellowships, pump priming, and pilot projects. Awards focused on operational delivery of cancer care were excluded. Awards were categorised by cancer type, cross-cutting research theme, and research phase. Funding amount was compared with global burden of specific cancers, measured by disability-adjusted life-years, years lived with disability, and mortality using data from the Global Burden of Disease study. FINDINGS: We identified 66 388 awards with total investment of about US$24·5 billion in 2016-20. Investment decreased year-on-year, with the largest drop observed between 2019 and 2020. Pre-clinical research received 73·5% of the funding across the 5 years ($18 billion), phase 1-4 clinical trials received 7·4% ($1·8 billion), public health research received 9·4% ($2·3 billion), and cross-disciplinary research received 5·0% ($1·2 billion). General cancer research received the largest investment ($7·1 billion, 29·2% of the total funding). The most highly funded cancer types were breast cancer ($2·7 billion [11·2%]), haematological cancer ($2·3 billion [9·4%]), and brain cancer ($1·3 billion [5·5%]). Analysis by cross-cutting theme revealed that 41·2% of investment ($9·6 billion) went to cancer biology research, 19·6% ($4·6 billion) to drug treatment research, and 12·1% ($2·8 billion) to immuno-oncology. 1·4% of the total funding ($0·3 billion) was spent on surgery research, 2·8% ($0·7 billion) was spent on radiotherapy research, and 0·5% ($0·1 billion) was spent on global health studies. INTERPRETATION: Cancer research funding must be aligned with the global burden of cancer with more equitable funding for cancer research in low-income and middle-income countries (which account for 80% of cancer burden), both to support research relevant to these settings, and build research capacity within these countries. There is an urgent need to prioritise investment in surgery and radiotherapy research given their primacy in the treatment of many solid tumours. FUNDING: None.

Risk-reducing surgery for individuals with cancer-predisposing germline pathogenic variants and no personal cancer history: a review of current UK guidelines.

Identifying healthy carriers of germline pathogenic variants in high penetrance cancer susceptibility genes offers the potential for risk-reducing surgery. The NHS England National Genomic Test Directory offers germline and somatic testing to patients with certain cancers or rare and inherited diseases, or, in some cases, to their relatives. This review summarises current UK guidelines for risk-reducing surgical interventions available for individuals with no personal history of cancer, who are determined to carry germline pathogenic variants. An electronic literature search of NICE guidelines and PubMed citable articles was performed. NICE guidelines are available for bilateral mastectomy and are currently in development for risk-reducing bilateral salpingo-oophorectomy. Guidelines developed with affiliation to, or through relevant British Surgical Societies or international consensus, are available for risk-reducing hysterectomy, polypectomy, gastrectomy, and thyroidectomy. There is a disparity in the development and distribution of national guidelines for interventions amongst tumour types. Whilst we are focusing on UK guidelines, we anticipate they will be relevant much more generally and so of interest to a wider audience including where there are no national guidelines to refer to. We suggest that, as genetic testing becomes rapidly more accessible, guideline development for interventions should be more closely aligned to those for testing.

Identifying research priorities in breast cancer surgery: a UK priority setting partnership with the James Lind Alliance.

PURPOSE: A James Lind Alliance priority setting partnership was developed to identify research priorities in breast cancer surgery from individuals with lived experience, at high genetic risk of breast cancer, and healthcare professionals (HCPs). METHODS: 'Uncertainties' were collected using an online survey. Following an evidence check and development of summary questions, an interim survey asked participants to rank their top 10 research priorities from the question list. Top-ranked questions from patient/carer, high-risk and professional groups were carried forward for discussion to a final online prioritisation workshop. RESULTS: 260 participants (101 patients/carers, 156 HCPs) submitted 940 uncertainties via the initial survey. These were analysed thematically into 128 summary questions in six topic areas. Following evidence checking, 59 questions were included in the interim survey which was completed by 572 respondents. Marked differences were seen in questions prioritised by patients/carers, HCPs and women at high-risk. The top eight priorities in patient/carer and professional groups and top two priorities for high-risk women were carried forward to the online workshop at which 22 participants discussed and agreed the final top 10. Key themes included de-escalation of breast and axillary surgery, factors impacting the development/detection of locoregional recurrence and optimal provision of support for informed treatment decision-making. CONCLUSION: The top 10 research priorities in breast cancer surgery have been agreed. However, the observed differences in research priorities identified by patients and professional groups were not anticipated. Top priorities from both groups should inform future UK breast cancer surgical research, to ensure that it addresses questions that are important to breast cancer community as a whole.

Bridging pre-surgical endocrine therapy for breast cancer during the COVID-19 pandemic: outcomes from the B-MaP-C study.

PURPOSE: The B-MaP-C study investigated changes to breast cancer care that were necessitated by the COVID-19 pandemic. Here we present a follow-up analysis of those patients commenced on bridging endocrine therapy (BrET), whilst they were awaiting surgery due to reprioritisation of resources. METHODS: This multicentre, multinational cohort study recruited 6045 patients from the UK, Spain and Portugal during the peak pandemic period (Feb-July 2020). Patients on BrET were followed up to investigate the duration of, and response to, BrET. This included changes in tumour size to reflect downstaging potential, and changes in cellular proliferation (Ki67), as a marker of prognosis. RESULTS: 1094 patients were prescribed BrET, over a median period of 53 days (IQR 32-81 days). The majority of patients (95.6%) had strong ER expression (Allred score 7-8/8). Very few patients required expedited surgery, due to lack of response (1.2%) or due to lack of tolerance/compliance (0.8%). There were small reductions in median tumour size after 3 months' treatment duration; median of 4 mm [IQR - 20, 4]. In a small subset of patients (n = 47), a drop in cellular proliferation (Ki67) occurred in 26 patients (55%), from high (Ki67 ≥ 10%) to low (< 10%), with at least one month's duration of BrET. DISCUSSION: This study describes real-world usage of pre-operative endocrine therapy as necessitated by the pandemic. BrET was found to be tolerable and safe. The data support short-term (≤ 3 months) usage of pre-operative endocrine therapy. Longer-term use should be investigated in future trials.

The Impact of Radiotherapy on Patient-reported Outcomes of Immediate Implant-based Breast Reconstruction With and Without Mesh.

OBJECTIVE: To explore the impact of PMRT on PROs of IBBR performed with and without mesh. SUMMARY OF BACKGROUND DATA: PMRT is increasingly given to improve breast cancer outcomes but can adversely impact complications after IBBR.Little; however, is known about the impact of PMRT on the PROs of IBBR, especially when mesh is used. METHODS: The implant Breast Reconstruction evAluation prospective cohort study recruited consecutive women undergoing immediate IBBR from 81 UK breast and plastic surgical units. Demographic, operative, oncological, and 3-month complication data were collected, and patients consented to receive validated PRO questionnaires at 18-months. The association between IBBR, PMRT, and PROs were investigated using mixed-effects regression models adjusted for clinically-relevant confounders and including a random-effect to account for potential clustering by center. RESULTS: A total of 1163 women consented to receive 18-month questionnaires of whom 730 (63%) completed it. Patients undergoing PMRT (214 patients) reported worse PROs in 3 BREAST-Q domains: satisfaction with breasts [-6.27 points, P = 0.008, 95% confidence interval (CI) (-10.91, -1.63)], satisfaction with outcome [-7.53 points, P = 0.002, CI (-12.20, -2.85)] and physical well-being [-6.55 points, P < 0.001, CI (-9.43, -3.67)]. Overall satisfaction was worse in the PMRT group [OR 0.497, P = 0.002, CI (0.32, 0.77)]. These effects were not ameliorated by mesh use. CONCLUSIONS: PMRT may adversely affect PROs after IBBR irrespective of whether mesh is used. These findings should be discussed with all patients considering IBBR and when indications for PMRT are borderline to enable informed decision-making regarding oncological and reconstructive treatment options. TRIAL REGISTRATION: ISRCTN37664281.

The impact of race and ethnicity in breast cancer-disparities and implications for precision oncology.

Breast cancer is the most commonly diagnosed cancer worldwide and is one of the leading causes of cancer death. The incidence, pathological features, and clinical outcomes in breast cancer differ by geographical distribution and across racial and ethnic populations. Importantly, racial and ethnic diversity in breast cancer clinical trials is lacking, with both Blacks and Hispanics underrepresented. In this forum article, breast cancer researchers from across the globe discuss the factors contributing to racial and ethnic breast cancer disparities and highlight specific implications of precision oncology approaches for equitable provision of breast cancer care to improve outcomes and address disparities.

Breast cancer management pathways during the COVID-19 pandemic: outcomes from the UK 'Alert Level 4' phase of the B-MaP-C study.

BACKGROUND: The B-MaP-C study aimed to determine alterations to breast cancer (BC) management during the peak transmission period of the UK COVID-19 pandemic and the potential impact of these treatment decisions. METHODS: This was a national cohort study of patients with early BC undergoing multidisciplinary team (MDT)-guided treatment recommendations during the pandemic, designated 'standard' or 'COVID-altered', in the preoperative, operative and post-operative setting. FINDINGS: Of 3776 patients (from 64 UK units) in the study, 2246 (59%) had 'COVID-altered' management. 'Bridging' endocrine therapy was used (n = 951) where theatre capacity was reduced. There was increasing access to COVID-19 low-risk theatres during the study period (59%). In line with national guidance, immediate breast reconstruction was avoided (n = 299). Where adjuvant chemotherapy was omitted (n = 81), the median benefit was only 3% (IQR 2-9%) using 'NHS Predict'. There was the rapid adoption of new evidence-based hypofractionated radiotherapy (n = 781, from 46 units). Only 14 patients (1%) tested positive for SARS-CoV-2 during their treatment journey. CONCLUSIONS: The majority of 'COVID-altered' management decisions were largely in line with pre-COVID evidence-based guidelines, implying that breast cancer survival outcomes are unlikely to be negatively impacted by the pandemic. However, in this study, the potential impact of delays to BC presentation or diagnosis remains unknown.

Short-term safety outcomes of mastectomy and immediate implant-based breast reconstruction with and without mesh (iBRA): a multicentre, prospective cohort study.

BACKGROUND: Use of biological or synthetic mesh might improve outcomes of immediate implant-based breast reconstruction-breast reconstruction with implants or expanders at the time of mastectomy-but there is a lack of high-quality evidence to support the safety or effectiveness of the technique. We aimed to establish the short-term safety of immediate implant-based breast reconstruction performed with and without mesh, to inform the feasibility of undertaking a future randomised clinical trial comparing different breast reconstruction techniques. METHODS: In this prospective, multicentre cohort study, we consecutively recruited women aged 16 years or older who had any type of immediate implant-based breast reconstruction for malignancy or risk reduction, with any technique, at 81 participating breast and plastic surgical units in the UK. Data about patient demographics and operative, oncological, and complication details were collected before and after surgery. Outcomes of interest were implant loss (defined as unplanned removal of the expander or implant), infection requiring treatment with antibiotics or surgery, unplanned return to theatre, and unplanned re-admission to hospital for complications of reconstructive surgery, up to 3 months after reconstruction and assessed by clinical review or patient self-report. Follow-up is complete. The study is registered with the ISRCTN Registry, number ISRCTN37664281. FINDINGS: Between Feb 1, 2014, and June 30, 2016, 2108 patients had 2655 mastectomies with immediate implant-based breast reconstruction at 81 units across the UK. 1650 (78%) patients had planned single-stage reconstructions (including 12 patients who had a different technique per breast). 1376 (65%) patients had reconstruction with biological (1133 [54%]) or synthetic (243 [12%]) mesh, 181 (9%) had non-mesh submuscular or subfascial implants, 440 (21%) had dermal sling implants, 42 (2%) had pre-pectoral implants, and 79 (4%) had other or a combination of implants. 3-month outcome data were available for 2081 (99%) patients. Of these patients, 182 (9%, 95% CI 8-10) experienced implant loss, 372 (18%, 16-20) required re-admission to hospital, and 370 (18%, 16-20) required return to theatre for complications within 3 months of their initial surgery. 522 (25%, 95% CI 23-27) patients required treatment for an infection. The rates of all of these complications are higher than those in the National Quality Standards (<5% for re-operation, re-admission, and implant loss, and <10% for infection). INTERPRETATION: Complications after immediate implant-based breast reconstruction are higher than recommended by national standards. A randomised clinical trial is needed to establish the optimal approach to immediate implant-based breast reconstruction. FUNDING: National Institute for Health Research, Association of Breast Surgery, and British Association of Plastic, Reconstructive and Aesthetic Surgeons.

Stem cell-like breast cancer cells with acquired resistance to metformin are sensitive to inhibitors of NADH-dependent CtBP dimerization.

Altered flux through major metabolic pathways is a hallmark of cancer cells and provides opportunities for therapy. Stem cell-like cancer (SCLC) cells can cause metastasis and therapy resistance. They possess metabolic plasticity, theoretically enabling resistance to therapies targeting a specific metabolic state. The C-terminal binding protein (CtBP) transcriptional regulators are potential therapeutic targets in highly glycolytic cancer cells, as they are activated by the glycolytic coenzyme nicotinamide adenine dinucleotide (NADH). However, SCLC cells commonly exist in an oxidative state with low rates of glycolysis. Metformin inhibits complex I of the mitochondrial electron transport chain; it can kill oxidative SCLC cells and has anti-cancer activity in patients. SCLC cells can acquire resistance to metformin through increased glycolysis. Given the potential for long-term metformin therapy, we have studied acquired metformin resistance in cells from the claudin-low subtype of breast cancer. Cells cultured for 8 weeks in sub-IC50 metformin concentration proliferated comparably to untreated cells and exhibited higher rates of glucose uptake. SCLC cells were enriched in metformin-adapted cultures. These SCLC cells acquired sensitivity to multiple methods of inhibition of CtBP function, including a cyclic peptide inhibitor of NADH-induced CtBP dimerization. Single-cell mRNA sequencing identified a reprogramming of epithelial-mesenchymal and stem cell gene expression in the metformin-adapted SCLC cells. These SCLC cells demonstrated an acquired dependency on one of these genes, Tenascin C. Thus, in addition to acquisition of sensitivity to glycolysis-targeting therapeutic strategies, the reprograming of gene expression in the metformin-adapted SCLC cells renders them sensitive to potential therapeutic approaches not directly linked to cell metabolism.

Development of Breast Cancer Choices: a decision support tool for young women with breast cancer deciding whether to have genetic testing for BRCA1/2 mutations.

PURPOSE: To develop a decision support tool for young women with breast cancer considering genetic testing for BRCA1/2 mutations soon after cancer diagnosis. METHODS: A four-stage iterative development process was employed; stage 1, literature review exploring the availability and efficacy of empirically tested decision support tools; stage 2, in-depth interviews with 29 young women (< 50 years) recently diagnosed with breast cancer, exploring information requirements and experiences of genetic testing decision making; stage 3, three focus groups (N = 21) exploring preferences for information presentation and prioritisation of content; stage 4, think-aloud interviews to refine the prototype (N = 16). RESULTS: Participants wanted information regarding the pros and cons of testing, the testing process and implications for their family, presented in a way that allowed them to choose the level of detail they required. They preferred the term 'altered gene', valued a medical word definition function and warnings before accessing sensitive information. CONCLUSION: Participants valued the decision support tool, the accessibility of the information and its clinical endorsement. The decision support tool has considerable clinical utility as an adjunct to genetic counselling or for use in busy oncology clinics where formal genetic counselling may be unavailable.

Opportunities and priorities for breast surgical research.

The 2013 Breast Cancer Campaign gap analysis established breast cancer research priorities without a specific focus on surgical research or the role of surgeons on breast cancer research. This Review aims to identify opportunities and priorities for research in breast surgery to complement the 2013 gap analysis. To identify these goals, research-active breast surgeons met and identified areas for breast surgery research that mapped to the patient pathway. Areas included diagnosis, neoadjuvant treatment, surgery, adjuvant therapy, and attention to special groups (eg, those receiving risk-reducing surgery). Section leads were identified based on research interests, with invited input from experts in specific areas, supported by consultation with members of the Association of Breast Surgery and Independent Cancer Patients' Voice groups. The document was iteratively modified until participants were satisfied that key priorities for surgical research were clear. Key research gaps included issues surrounding overdiagnosis and treatment; optimising treatment options and their selection for neoadjuvant therapies and subsequent surgery; reducing rates of re-operations for breast-conserving surgery; generating evidence for clinical effectiveness and cost-effectiveness of breast reconstruction, and mechanisms for assessing novel interventions; establishing optimal axillary management, especially post-neoadjuvant treatment; and defining and standardising indications for risk-reducing surgery. We propose strategies for resolving these knowledge gaps. Surgeons are ideally placed for a central role in breast cancer research and should foster a culture of engagement and participation in research to benefit patients and health-care systems. Development of infrastructure and surgical research capacity, together with appropriate allocation of research funding, is needed to successfully address the key clinical and translational research gaps that are highlighted in this Review within the next two decades.

Germline BRCA mutation and outcome in young-onset breast cancer (POSH): a prospective cohort study.

BACKGROUND: Retrospective studies provide conflicting interpretations of the effect of inherited genetic factors on the prognosis of patients with breast cancer. The primary aim of this study was to determine the effect of a germline BRCA1 or BRCA2 mutation on breast cancer outcomes in patients with young-onset breast cancer. METHODS: We did a prospective cohort study of female patients recruited from 127 hospitals in the UK aged 40 years or younger at first diagnosis (by histological confirmation) of invasive breast cancer. Patients with a previous invasive malignancy (except non-melanomatous skin cancer) were excluded. Patients were identified within 12 months of initial diagnosis. BRCA1 and BRCA2 mutations were identified using blood DNA collected at recruitment. Clinicopathological data, and data regarding treatment and long-term outcomes, including date and site of disease recurrence, were collected from routine medical records at 6 months, 12 months, and then annually until death or loss to follow-up. The primary outcome was overall survival for all BRCA1 or BRCA2 mutation carriers (BRCA-positive) versus all non-carriers (BRCA-negative) at 2 years, 5 years, and 10 years after diagnosis. A prespecified subgroup analysis of overall survival was done in patients with triple-negative breast cancer. Recruitment was completed in 2008, and long-term follow-up is continuing. FINDINGS: Between Jan 24, 2000, and Jan 24, 2008, we recruited 2733 women. Genotyping detected a pathogenic BRCA mutation in 338 (12%) patients (201 with BRCA1, 137 with BRCA2). After a median follow-up of 8·2 years (IQR 6·0-9·9), 651 (96%) of 678 deaths were due to breast cancer. There was no significant difference in overall survival between BRCA-positive and BRCA-negative patients in multivariable analyses at any timepoint (at 2 years: 97·0% [95% CI 94·5-98·4] vs 96·6% [95·8-97·3]; at 5 years: 83·8% [79·3-87·5] vs 85·0% [83·5-86·4]; at 10 years: 73·4% [67·4-78·5] vs 70·1% [67·7-72·3]; hazard ratio [HR] 0·96 [95% CI 0·76-1·22]; p=0·76). Of 558 patients with triple-negative breast cancer, BRCA mutation carriers had better overall survival than non-carriers at 2 years (95% [95% CI 89-97] vs 91% [88-94]; HR 0·59 [95% CI 0·35-0·99]; p=0·047) but not 5 years (81% [73-87] vs 74% [70-78]; HR 1·13 [0·70-1·84]; p=0·62) or 10 years (72% [62-80] vs 69% [63-74]; HR 2·12 [0·82-5·49]; p= 0·12). INTERPRETATION: Patients with young-onset breast cancer who carry a BRCA mutation have similar survival as non-carriers. However, BRCA mutation carriers with triple-negative breast cancer might have a survival advantage during the first few years after diagnosis compared with non-carriers. Decisions about timing of additional surgery aimed at reducing future second primary-cancer risks should take into account patient prognosis associated with the first malignancy and patient preferences. FUNDING: Cancer Research UK, the UK National Cancer Research Network, the Wessex Cancer Trust, Breast Cancer Now, and the PPP Healthcare Medical Trust Grant.

Increased circulating resistin levels in early-onset breast cancer patients of normal body mass index correlate with lymph node negative involvement and longer disease free survival: a multi-center POSH cohort serum proteomics study.

BACKGROUND: Early-onset breast cancer (EOBC) affects about one in 300 women aged 40 years or younger and is associated with worse outcomes than later onset breast cancer. This study explored novel serum proteins as surrogate markers of prognosis in patients with EOBC. METHODS: Serum samples from EOBC patients (stages 1-3) were analysed using agnostic high-precision quantitative proteomics. Patients received anthracycline-based chemotherapy. The discovery cohort (n = 399) either had more than 5-year disease-free survival (DFS) (good outcome group, n = 203) or DFS of less than 2 years (poor outcome group, n = 196). Expressed proteins were assessed for differential expression between the two groups. Bioinformatics pathway and network analysis in combination with literature research were used to determine clinically relevant proteins. ELISA analysis against an independent sample set from the Prospective study of Outcomes in Sporadic versus Hereditary breast cancer (POSH) cohort (n = 181) was used to validate expression levels of the selected target. Linear and generalized linear modelling was applied to determine the effect of target markers, body mass index (BMI), lymph node involvement (LN), oestrogen receptor (ER), progesterone receptor and human epidermal growth factor receptor 2 status on patients' outcome. RESULTS: A total of 5346 unique proteins were analysed (peptide FDR p ≤ 0.05). Of these, 812 were differentially expressed in the good vs poor outcome groups and showed significant enrichment for the insulin signalling (p = 0.01) and the glycolysis/gluconeogenesis (p = 0.01) pathways. These proteins further correlated with interaction networks involving glucose and fatty acid metabolism. A consistent nodal protein to these metabolic networks was resistin (upregulated in the good outcome group, p = 0.009). ELISA validation demonstrated resistin to be upregulated in the good outcome group (p = 0.04), irrespective of BMI and ER status. LN involvement was the only covariate with a significant association with resistin measurements (p = 0.004). An ancillary in-silico observation was the induction of the inflammatory response, leucocyte infiltration, lymphocyte migration and recruitment of phagocytes (p < 0.0001, z-score > 2). Survival analysis showed that resistin overexpression was associated with improved DFS. CONCLUSIONS: Higher circulating resistin correlated with node-negative patients and longer DFS independent of BMI and ER status in women with EOBC. Overexpression of serum resistin in EOBC may be a surrogate indicator of improved prognosis.

Local Recurrence and Breast Oncological Surgery in Young Women With Breast Cancer: The POSH Observational Cohort Study.

OBJECTIVE: To assess clinical and surgical factors affecting local recurrence and survival in young breast cancer patients in the Prospective study of Outcomes in Sporadic versus Hereditary breast cancer (POSH). BACKGROUND: Emerging data suggest young age is a predictor of increased local recurrence. METHODS: POSH is a prospective cohort of 3024 women of 18 to 40 years with breast cancer. Cohort characteristics were grouped by mastectomy or BCS. Endpoints were local-recurrence interval (LRI), distant disease-free interval (DDFI), and overall survival (OS); described using cumulative-hazard and Kaplan-Meier plots and multivariable analyses by Flexible Parametric and Cox regression models. RESULTS: Mastectomy was performed in 1464 patients and breast-conserving surgery (BCS) in 1395. Patients undergoing mastectomy had larger tumors and higher proportions of positive family history, estrogen receptor+, progesterone receptor+, and/or human epidermal growth factor receptor 2+ tumors. Local events accounted for 15% of recurrences. LRI by surgical type varied over time with LRI similar at 18 months (1.0% vs 1.0%, P = 0.348) but higher for BCS at 5 and 10 years (5.3% vs 2.6%, P < 0.001; and 11.7% vs 4.9%, P < 0.001, respectively). Similar results were found in the adjusted model. Conversely, distant-metastases and deaths were lower for BCS but not after adjusting for prognostic factors. After mastectomy chest-wall radiotherapy was associated with improved LRI (hazard ratio, HR = 0.46, P = 0.015). Positive surgical margins, and development of local recurrence predicted for reduced DDFI (HR = 0.50, P < 0.001; and HR = 0.29, P = 0.001, respectively). CONCLUSIONS: Surgical extent appears less important for DDFI than completeness of excision or, where appropriate, chest-wall radiotherapy. Despite higher local-recurrence rates for BCS, surgical type does not influence DDFI or OS after adjusting for known prognostic factors in young breast cancer patients.