How appropriate is treating patients diagnosed with advanced esophageal cancer with anticancer drugs? A multicenter retrospective cohort Spanish study.

AIM: To assess the appropriateness of systemic oncological treatments (SOT) provided to patients diagnosed with advanced esophageal cancer (EC) across a group of participating hospitals. METHODS: Multicenter, retrospective cohort study in five Spanish hospitals including newly confirmed advanced EC cases between July 1, 2014, and June 30, 2016, with a 5-year follow-up. RESULTS: We identified 157 patients fulfilling the inclusion criteria (median age: 65 years, 85.9% males). Most patients, 125 (79.6%) were treated at least with one active treatment, and 33% received two or more lines of SOT. The 1-, 2- and 5-year overall survival rates were 30.3% [95%CI: 23.8, 38.7], 14.0% [95%CI: 9.3, 21.0], and 7.1% [95% CI: 3.8, 13.1] respectively, and the median survival time 8 months (95% CI: 6, 19) for stages IIIb IIIc and 7 months (95% CI: 5, 9) for stage IV. Clinical stage, receiving more than one line of SOT, and treatment with radiotherapy accelerated the time to death (0.4, 0.9-, and 0.8-times shorter survival respectively, p < 0.05). Better performance status (ECOG < 2) extended survival time by 2.2 times (p = 0.04). Age < 65 years (OR 9.4, 95% CI 3.2, 31.4, p < 0.001), and being treated in one particular hospital (OR 0.2, 95% CI 0.0, 0.8, p < 0.01) were associated with the administration of two or more lines of SOT. Altogether, 18.9% and 9.0% of patients received chemotherapy in the last four and two weeks of life, respectively. Moreover, 2.5% of patients were prescribed a new line of chemotherapy during the last month of life. The proportion of all patients who did not have access to palliative care reached 29.3%, and among those who had access to it, 34.2% initiated it in the last month of life. CONCLUSION: A high proportion of advanced EC patients receive many treatments not based on sound evidence and they do not benefit enough from palliative care services. The most accepted appropriateness indicators point out that some of the analyzed patients could have been overtreated. This study provides important insights into the quality of care provided to advanced EC, and furthermore, for giving valuable insight and opportunities for improvement.

Anticancer Drugs Compared to No Anticancer Drugs in Patients with Advanced Hepatobiliary Cancer: A Mapping Review and Evidence Gap Map.

Introduction: Despite being commonly recommended, the impact of anticancer drugs (ACDs) on patient-important outcomes beyond survival for advanced hepatobiliary cancers (HBCs) may not have been sufficiently assessed. We aim to identify and map the evidence regarding ACDs versus best supportive care (BSC) for advanced HBCs, considering patient-centered outcomes. Methods: In this mapping review, we included systematic reviews, randomized controlled trials, quasi-experimental, and observational studies comparing ACDs (chemotherapy, immunotherapy, biological/targeted therapy) versus BSC for advanced HBCs. We searched MEDLINE (PubMed), EMBASE (Ovid), Cochrane Library, Epistemonikos, PROSPERO and clinicaltrials.gov for eligible studies. Two reviewers performed the screening and data extraction processes. We developed evidence maps for each type of cancer. Results: We included 87 studies (60 for advanced liver cancer and 27 for gallbladder or bile duct cancers). Most of the evidence favored ACDs for survival outcomes, and BSC for toxicity. We identified several evidence gaps for non-survival outcomes, including quality of life or quality of end-of-life care. Discussion: Patient-important outcomes beyond survival in advanced HBCs are insufficiently assessed by the available evidence. Future studies need to address these gaps to better inform decision-making processes.

Systemic Oncological Treatments versus Supportive Care for Patients with Advanced Hepatobiliary Cancers: An Overview of Systematic Reviews.

BACKGROUND: The trade-off between systemic oncological treatments (SOTs) and UPSC in patients with primary advanced hepatobiliary cancers (HBCs) is not clear in terms of patient-centred outcomes beyond survival. This overview aims to assess the effectiveness of SOTs (chemotherapy, immunotherapy and targeted/biological therapies) versus UPSC in advanced HBCs. METHODS: We searched for systematic reviews (SRs) in PubMed, EMBASE, the Cochrane Library, Epistemonikos and PROSPERO. Two authors assessed eligibility independently and performed data extraction. We estimated the quality of SRs and the overlap of primary studies, performed de novo meta-analyses and assessed the certainty of evidence for each outcome. RESULTS: We included 18 SRs, most of which were of low quality and highly overlapped. For advanced hepatocellular carcinoma, SOTs showed better overall survival (HR = 0.62, 95% CI 0.55-0.77, high certainty for first-line therapy; HR = 0.85, 95% CI 0.79-0.92, moderate certainty for second-line therapy) with higher toxicity (RR = 1.18, 95% CI 0.87-1.60, very low certainty for first-line therapy; RR = 1.58, 95% CI 1.28-1.96, low certainty for second-line therapy). Survival was also better for SOTs in advanced gallbladder cancer. No outcomes beyond survival and toxicity could be meta-analysed. CONCLUSION: SOTs in advanced HBCs tend to improve survival at the expense of greater toxicity. Future research should inform other patient-important outcomes to guide clinical decision making.

Systemic oncological treatments in patients with advanced pancreatic cancer: a scoping review and evidence map.

PURPOSE: To identify, describe, and organise currently available evidence regarding systemic oncological treatments (SOTs) (chemotherapy, targeted/biological therapies, and immunotherapy) compared to best supportive care (BSC) for patients with advanced pancreatic cancer (PC). METHODS: We conducted a scoping review and evidence mapping, adhering to PRISMA-ScR checklist. We searched MEDLINE, EMBASE, Cochrane Library, Epistemonikos, PROSPERO, and clinicaltrials.gov for eligible studies. We included systematic reviews (SRs), randomised controlled trials (RCTs), quasi-experimental, and observational studies evaluating SOTs compared to BSC or no treatment in patients with advanced PC. Two independent reviewers performed the screening process and data extraction. We developed evidence maps as an interactive visualization display, including the assessed interventions and outcomes. RESULTS: Of the 50,601 records obtained from our search, we included 43 studies: 2 SRs, 16 RCTs, 4 quasi-experimental studies, 20 observational studies, and 1 protocol for a quasi-experimental study. Forty-two studies reported survival-related outcomes and most favoured SOTs, while five reported toxicity and most favoured BSC. Other patient-centred outcomes, such as quality of life, were scarcely reported. CONCLUSIONS: This study highlights the current evidence gaps in studies assessing treatments for patients with advanced PC, mainly the lack of reports of non-survival-related outcomes, pointing out research areas that need further attention to make better recommendations for these patients.

Pharmacogenetic Profiling in High-Risk Soft Tissue Sarcomas Treated with Neoadjuvant Chemotherapy.

Neoadjuvant chemotherapy based on anthracyclines and ifosfamide for high-risk soft tissue sarcomas (STS) of the extremities and trunk is a controversial treatment option. There are substantial interindividual differences in clinical outcomes in patients treated with neoadjuvant chemotherapy. The aim of this study was to evaluate, as biomarkers, polymorphisms in genes encoding drug-metabolizing enzymes, drug transporters, or drug targets and their association with toxicity and survival in STS patients treated with neoadjuvant chemotherapy. We analysed variants in genes involved in anthracycline metabolism (ABCB1, ABCC2, NQO1, CBR3, and SLC22A16) and in ifosfamide catabolism (ALDH1A1) in 79 treated patients. Two genes showed significant association after adjusted multivariate analysis: ABCC2 and ALDH1A1. In patients treated with anthracyclines, ABCC2 rs3740066 was associated with risk of febrile neutropenia (p = 0.031), and with decreased overall survival (OS) (p = 0.024). ABCC2 rs2273697 was associated with recurrence-free survival (RFS) (p = 0.024). In patients treated with ifosfamide, ALDH1A1 rs3764435 was associated with RFS (p = 0.046). Our pharmacogenetic study shows for the first time that variants in genes regulating the metabolism of neoadjuvant chemotherapy may be helpful to predict toxicity and survival benefit in high-risk STS treated with neoadjuvant chemotherapy. Further validation studies are needed to establish their clinical utility.

The value of sentinel lymph-node biopsy after neoadjuvant therapy: an overview.

PURPOSE: We conducted a systematic review to analyse the performance of the sentinel lymph-node biopsy (SLNB) after the neoadjuvant chemotherapy, compared to axillary lymph-node dissection, in terms of false-negative rate (FNR) and sentinel lymph-node identification rate (SLNIR), sensitivity, negative predictive value (NPV), need for axillary lymph-node dissection (ALND), morbidity, preferences, and costs. METHODS: MEDLINE, Embase, Scopus, and The Cochrane Library were searched. We assessed the quality of the included systematic reviews using AMSTAR2 tool, and estimated the degree of overlapping of the individual studies on the included reviews. RESULTS: Six systematic reviews with variable quality were selected. We observed a very high overlapping degree across the included reviews. The FNR and the SLNIR were quite consistent (FNR 13-14%; SLNIR ~ 90% or higher). In women with initially clinically node-negative breast cancer, the FNR was better (6%), with similar SLNIR (96%). The included reviews did not consider the other prespecified outcomes. CONCLUSIONS: It would be reasonable to suggest performing an SLNB in patients treated with NACT, adjusting the procedure to the previous marking of the affected lymph node, using double tracer, and biopsy of at least three sentinel lymph nodes. More well-designed research is needed. PROSPERO registration number: CRD42020114403.

Long-Term Risk of Breast Cancer after Diagnosis of Benign Breast Disease by Screening Mammography.

Assessing the long-term risk of breast cancer after diagnosis of benign breast disease by mammography is of utmost importance to design personalised screening strategies. We analysed individual-level data from 778,306 women aged 50-69 years with at least one mammographic screening participation in any of ten breast cancer screening centers in Spain from 1996 to 2015, and followed-up until 2017. We used Poisson regression to compare the rates of incident breast cancer among women with and without benign breast disease. During a median follow-up of 7.6 years, 11,708 (1.5%) women had an incident of breast cancer and 17,827 (2.3%) had a benign breast disease. The risk of breast cancer was 1.77 times higher among women with benign breast disease than among those without (95% CI: 1.61 to 1.95). The relative risk increased to 1.99 among women followed for less than four years, and remained elevated for two decades, with relative risk 1.96 (95% CI: 1.32 to 2.92) for those followed from 12 to 20 years. Benign breast disease is a long-term risk factor for breast cancer. Women with benign breast disease could benefit from closer surveillance and personalized screening strategies.

European clinical practice guidelines on the use of chemotherapy for advanced oesophageal and gastric cancers: a critical review using the AGREE II and the AGREE-REX instruments.

PURPOSE: To assess the methodological quality of all relevant and recent European clinical practice guidelines (CPGs) for advanced oesophageal and gastric cancers, and to synthesise their recommendations on the use of chemotherapy. METHODS: We searched PubMed, EMBASE, guidelines repositories, and other sources from 2010 onwards. We appraised quality using AGREE-II and AGREE-REX. RESULTS: 11 CPGs were included (five high, five low, and one moderate quality). Most guidelines showed deficiencies in the domain "applicability", with only three scoring above 60%. Nine did not report having sought the views and preferences of the target population. The lowest scores for AGREE-REX were item Values and Preferences of Target Users (1.6; SD 1.3), and item Values and Preferences of Policy/Decision-Makers (1.8; SD 1.7). The domain Clinical Applicability got the highest score and the domain Implementability got the lowest. CONCLUSIONS: An urgent area of research is how to develop credible and implementable recommendations on the clinical use of CT for advanced oesophageal and gastric cancer. SYSTEMATIC REVIEW REGISTRATION: PROSPERO (CRD42021236753).

Coping experiences of women in the different phases of breast cancer.

PURPOSE: To understand the evolution of coping among women diagnosed with breast cancer over time, and the effect of age and family income on coping. METHOD: Using a phenomenological qualitative study, data was collected through semi-structured interviews with sixteen women in a hospital in Barcelona (Spain) between January 2018 and June 2019. An analysis of thematic content and discursive profile was carried out, assisted by the Nvivo v.12 program. RESULTS: Coping strategies change according to the meaning of breast cancer in each phase and the age and family income. In the acute phase, multiple coping strategies are identified, and this variety was more frequent among the young women in the study. In the extended phase, planning, distancing, and seeking social support become important. The latter used during treatment by older women in the study, regardless of family income. In the follow-up phase, distancing stands out, but also the search for social support among young women with fewer resources. CONCLUSIONS: Coping with breast cancer evolves according to the meaning that the disease receives in each phase. In addition, the analysis by discursive profile shows how the social support context is also related to the coping strategies in each phase.

Opinión de los especialistas de medicina preventiva y salud pública acerca de las recomendaciones sobre las prácticas de bajo valor: encuesta piloto / Preventive medicine and public health specialists' opinion about recommendations of low-value practices: a pilot survey

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Intermittent androgen deprivation therapy: recommendations to improve the management of patients with prostate cancer following the GRADE approach.

PURPOSE: The purpose of this study was to provide evidence-based recommendations of intermittent androgen deprivation therapy (IADT) compared with continuous androgen deprivation therapy (CADT) for men with prostate cancer (PCA). METHODS: We conducted a comprehensive search in MEDLINE, EMBASE, The Cochrane Library, CINAHL, and ECONLIT, from the database inception to December 2017. We adhered to the Grading of Recommendations, Assessment, Development and Evaluation framework to assess the quality of the evidence and to formulate recommendations. RESULTS: We included one systematic review with 15 trials as well as three additional studies that assessed IADT versus CADT, all of them focused on PCA patients in advanced stages. The findings did not show differences for critical and important outcomes, including adverse events. Trials reported the benefits of IADT in terms of selected domains of health-related quality of life, although with high heterogeneity. Evidence quality was considered moderate or low for most of the assessed outcomes. We identified a patient preference study reporting a high preference for IADT, due to issues related to quality of life, general well-being, and side effects, among others. We did not identify economic studies comparing these regimes. We formulate four recommendations: one no-recommendation, one conditional recommendation, and two good practice points. CONCLUSION: For men in early stages of PCA, it is not possible to make any recommendation about the preferable use of IADT or CADT due to the lack of available evidence. For men in advanced stages of the disease, an IADT should be considered as soon as clinically reasonable (weak recommendation and low certainty of the evidence). Clinicians should discuss the risks and benefits of IADT and CADT with their patients, taking into account their values and preferences.

Biomarkers expression in benign breast diseases and risk of subsequent breast cancer: a case-control study.

Women with benign breast diseases (BBD) have a high risk of breast cancer. However, no biomarkers have been clearly established to predict cancer in these women. Our aim was to explore whether estrogen receptor (ER), progesterone receptor (PR), and Ki67 expression stratify risk of breast cancer in screened women with BBD. We conducted a nested case-control study. Women with breast cancer and prior BBDs (86 cases) were matched to women with prior BBDs who were free from breast cancer (172 controls). The matching factors were age at BBD diagnosis, type of BBD, and follow-up time since BBD diagnosis. ER, PR, and Ki67 expression were obtained from BBDs' specimens. Conditional logistic regression was used to estimate odds ratios (ORs), and 95% confidence intervals (CIs) of breast cancer risk according to ER, PR, and Ki67 expression. Women with >90% of ER expression had a higher risk of breast cancer (OR = 2.63; 95% CI: 1.26-5.51) than women with ≤70% of ER expression. Similarly, women with >80% of PR expression had a higher risk of breast cancer (OR = 2.22; 95% CI: 1.15-4.27) than women with ≤40% of PR expression. Women with proliferative disease and ≥1% of Ki67 expression had a nonsignificantly increased risk of breast cancer (OR = 1.16; 95% CI: 0.46-2.90) than women with <1% of Ki67 expression. A high expression of ER and PR in BBD is associated with an increased risk of subsequent breast cancer. In proliferative disease, high Ki67 expression may also have an increased risk. This information is helpful to better characterize BBD and is one more step toward personalizing the clinical management of these women.

DianaHealth.com, an On-Line Database Containing Appraisals of the Clinical Value and Appropriateness of Healthcare Interventions: Database Development and Retrospective Analysis.

OBJECTIVE: To describe the development of a novel on-line database aimed to serve as a source of information concerning healthcare interventions appraised for their clinical value and appropriateness by several initiatives worldwide, and to present a retrospective analysis of the appraisals already included in the database. METHODS AND FINDINGS: Database development and a retrospective analysis. The database DianaHealth.com is already on-line and it is regularly updated, independent, open access and available in English and Spanish. Initiatives are identified in medical news, in article references, and by contacting experts in the field. We include appraisals in the form of clinical recommendations, expert analyses, conclusions from systematic reviews, and original research that label any health care intervention as low-value or inappropriate. We obtain the information necessary to classify the appraisals according to type of intervention, specialties involved, publication year, authoring initiative, and key words. The database is accessible through a search engine which retrieves a list of appraisals and a link to the website where they were published. DianaHealth.com also provides a brief description of the initiatives and a section where users can report new appraisals or suggest new initiatives. From January 2014 to July 2015, the on-line database included 2940 appraisals from 22 initiatives: eleven campaigns gathering clinical recommendations from scientific societies, five sets of conclusions from literature review, three sets of recommendations from guidelines, two collections of articles on low clinical value in medical journals, and an initiative of our own. CONCLUSIONS: We have developed an open access on-line database of appraisals about healthcare interventions considered of low clinical value or inappropriate. DianaHealth.com could help physicians and other stakeholders make better decisions concerning patient care and healthcare systems sustainability. Future efforts should be focused on assessing the impact of these appraisals in the clinical practice.

Risk of Breast Cancer in Women with False-Positive Results according to Mammographic Features.

Purpose To assess the risk of breast cancer in women with false-positive screening results according to radiologic classification of mammographic features. Materials and Methods Review board approval was obtained, with waiver of informed consent. This retrospective cohort study included 521 200 women aged 50-69 years who underwent screening as part of the Spanish Breast Cancer Screening Program between 1994 and 2010 and who were observed until December 2012. Cox proportional hazards regression analysis was used to estimate the age-adjusted hazard ratio (HR) of breast cancer and the 95% confidence interval (CI) in women with false-positive mammograms as compared with women with negative mammograms. Separate models were adjusted for screen-detected and interval cancers and for screen-film and digital mammography. Time without a breast cancer diagnosis was plotted by using Kaplan-Meier curves. Results When compared with women with negative mammograms, the age-adjusted HR of cancer in women with false-positive results was 1.84 (95% CI: 1.73, 1.95; P < .001). The risk was higher in women who had calcifications, whether they were (HR, 2.73; 95% CI: 2.28, 3.28; P < .001) or were not (HR, 2.24; 95% CI: 2.02, 2.48; P < .001) associated with masses. Women in whom mammographic features showed changes in subsequent false-positive results were those who had the highest risk (HR, 9.13; 95% CI: 8.28, 10.07; P < .001). Conclusion Women with false-positive results had an increased risk of breast cancer, particularly women who had calcifications at mammography. Women who had more than one examination with false-positive findings and in whom the mammographic features changed over time had a highly increased risk of breast cancer. Previous mammographic features might yield useful information for further risk-prediction models and personalized follow-up screening protocols. (©) RSNA, 2016 Online supplemental material is available for this article.

Breast cancer risk after diagnosis by screening mammography of nonproliferative or proliferative benign breast disease: a study from a population-based screening program.

Benign breast disease increases the risk of breast cancer. This association has scarcely been evaluated in the context of breast cancer screening programs although it is a prevalent finding in mammography screening. We assessed the association of distinct categories of benign breast disease and subsequent risk of breast cancer, as well as the influence of a family history of breast cancer. A retrospective cohort study was conducted in 545,171 women aged 50-69 years biennially screened for breast cancer in Spain. The median of follow-up was 6.1 years. The age-adjusted rate ratio (RR) of breast cancer for women with benign breast disease, histologically classified into nonproliferative and proliferative disease with and without atypia, compared with women without benign breast disease was estimated by Poisson regression analysis. A stratified analysis by family history of breast cancer was performed in a subsample. All tests were two-sided. The age-adjusted RR of breast cancer after diagnosis of benign breast disease was 2.51 (95 % CI: 2.14-2.93) compared with women without benign breast disease. The risk was higher in women with proliferative disease with atypia (RR = 4.56, 95 % CI: 2.06-10.07) followed by those with proliferative disease without atypia (RR = 3.58; 95 % CI = 2.61-4.91). Women with nonproliferative disease and without a family history of breast cancer remained also at increased risk of cancer (OR = 2.23, 95 % CI: 1.86-2.68). An increased risk of breast cancer was observed among screening participants with proliferative or nonproliferative benign breast disease, regardless of a family history of breast cancer. This information may be useful to explore risk-based screening strategies.

APC and KRAS mutations in distal colorectal polyps are related to smoking habits in men: results of a cross-sectional study.

BACKGROUND: The purpose of this study was (a) to evaluate the association between cigarette smoking and the prevalence of distal colorectal polyps and adenocarcinoma and (b) to analyse genetic alterations representing different molecular pathways of the colorectal carcinogenesis. METHODS: A total of 623 asymptomatic male (mean age: 53 years; 50-65) car factory workers were included. Information on smoking habits and other lifestyle factors were collected followed by a 60 cm colonoscopy. APC and KRAS mutations and microsatellite status were determined in colorectal lesions (colorectal carcinoma (CRC), hyperplastic (HP) and adenomatous polyps (AP)). Data were analysed using unconditional multiple logistic regression models. RESULTS: Smokers had a higher prevalence of AP (OR 2.1; 95% CI 1.2-3.6; p<0.05) and HP (OR 5.4; 95% CI 2.6- 11.1; p<0.05). No differences in CRC were observed. There was a dose-response relationship with the number of cigarettes smoked. The risk of developing AP or HP decreased after smoking cessation, even among heavy smokers (≥20 packs/year). KRAS mutations were more prevalent among smokers AP (OR 5.6; 95% CI 1.6-20.4; p=0.007). There was a trend of positive association with APC mutations (OR 3.5; 95% CI 0.9-4.4; p=0.096). APC and KRAS mutations were found in 36% and 61% of the HP of smokers, but were absent in non-smokers (p=0.89 and 0.78, respectively). There were no differences in MSI between smokers and non-smokers. CONCLUSIONS: Cigarette smoking is associated with a higher risk of developing both HP and AP and a higher prevalence of mutations in APC and KRAS.

Prevalencia de tratamiento hormonal sustitutivo en mujeres que participan en un programa de cribado de cáncer de mama / Prevalence of use of hormone replacement therapy in women participating in a breast cancer screening program

Fundamento y objetivo: Determinar la prevalencia y el tipo de tratamiento hormonal sustitutivo (THS) en participantes de un programa de cribado de cáncer de mama de Barcelona. Pacientes y método: La prevalencia de consumo de THS se obtuvo a través de una encuesta. Se recogió información sobre tipo de THS, antecedentes ginecológicos, situación laboral y nivel de estudios. La prevalencia se calculó con sus intervalos de confianza (IC) del 95%. Resultados: Entre mayo de 2001 y junio de 2005 participaron en el programa de cribado de cáncer de mama 21.835 mujeres con una edad media de 57,6 años (el 86,7% posmenopáusicas). La prevalencia confirmada de consumo de THS fue del 5,2% (IC del 95%: 5,3–6,0), y se administró con mayor frecuencia a mujeres entre 55 y 59 años. Los tipos más frecuentes fueron la tibolona (39,5%) y la combinación de estrógenos y progestágenos (30,4%). El nivel educativo alto se relacionó con mayor consumo de THS. No hubo diferencias estadísticamente significativas en el resultado del cribado según consumo o tipo de THS. Conclusiones: La prevalencia de uso del THS fue del 5,2%. Los tipos de THS más frecuentes fueron la tibolona y la combinación de estrógenos y progestágenos (AU)

Background and objective: the purpose of the study was to determine the prevalence and type of hormone replacement therapy (HRT) in participants in a breast cancer screening program (BCSP) in Barcelona. Patients and Method: Prevalence of use of HRT was obtained through a survey. Information about type of HRT, gynecological history and socioeconomic and educational level was collected. Prevalence was calculated with its corresponding 95% confidence interval. Results: From May 2001 to June 2005 there were 21835 participants in the BCSP with a mean age of 57,6 years. Most of the participants were postmenopausal (86,7%). Confirmed prevalence of use of HRT was 5,2%(CI95% 5,3–6,0) with a greater use among women aged 55 to 59 years. The most frequent types of HRT were tibolone (39,5%) followed by combined estrogens plus progestin (30,4%). Higher education was associated with a higher use of HRT. Neither the use or the type of HRT influenced the results of the screening program. Conclusions: Prevalence of use of HRT was 5,2% in this study. The most frequently used agents were tibolone and combined estrogens plus progestin (AU)

Phenotypic characterization and risk factors for interval breast cancers in a population-based breast cancer screening program in Barcelona, Spain.

OBJECTIVE: To analyze phenotypic classification and other risk factors for interval breast cancer, focusing on true interval and false negative cancers. METHODS: A nested case-control study was performed among 115 cancers detected between two screening mammograms (interval cancers) and 115 screen-detected cancers diagnosed between 1995 and 2008 in a population-based breast cancer screening program in Barcelona (Spain). Bivariate and multivariate analyses were performed to compare patient and tumor molecular characteristics among all interval cancers, true intervals and false negatives, and screen-detected cancers. RESULTS: A total of 42.5% of interval cancers were true interval tumors and 16.2% were false negatives. High breast density and triple negative phenotype were more frequent in true interval cancers than in screen-detected cancers (57.6 and 34.1%, respectively for breast density, p = 0.023; 28.1 and 7.5%, respectively for triple negative phenotype, p = 0.028), while no statistically significant differences were observed between false negatives and screen-detected cancers. The main adjusted factors associated with true interval cancers compared with screen-detected cancers were high breast density and triple negative phenotype (OR = 3.1, 95% CI, 1.03-9.24 and OR = 8.9, 95% CI, 2.03-38.62, respectively). CONCLUSION: A more aggressive molecular phenotype and high breast density were identified in breast tumors that truly arise in the interval between screenings.