Danish Breast Cancer Cooperative Group

Residual Axillary Metastases in Node-Positive Breast Cancer Patients After Neoadjuvant Treatment: A Register-Based Study

BACKGROUND

Lymph node (LN) metastasis after neoadjuvant chemotherapy (NACT) generally warrants axillary lymph node dissection, which opposes guidelines of upfront surgery in many cases. We investigated the risk of having additional metastases in the axilla when the LNs removed by targeted axillary dissection (TAD) harbored metastases after NACT. We aimed to identify subgroups suitable for de-escalated axillary treatment.

METHODS

This register-based study used data from the Danish Breast Cancer Cooperative Group database. Data were analyzed with logistic regression models. The primary outcome was the metastatic burden in non-TAD LNs in patients with positive TAD LNs after NACT.

RESULTS

Among 383 patients, < 66.6% positive TAD LNs (adjusted odds ratio [OR] 0.34, 95% confidence interval [CI] 0.17-0.62), only isolated tumor cells (ITCs) [OR 0.11, 95% CI < 0.01-0.82], and breast pathological complete response (pCR) [OR 0.07, 95% CI < 0.01-0.56] were associated with a low risk of having more than three positive non-TAD LNs. In 315 patients with fewer than three positive non-TAD LNs, the proportion of positive TAD LNs (OR 0.45, 95% CI 0.27-0.76 for 33.3-66.6% vs. > 66.6%), size of the TAD LN metastasis (OR 0.14, 95% CI 0.04-0.54 for ITC vs. macrometastasis), tumor size at diagnosis (OR 0.30, 95% CI 0.15-0.64 for 20-49 mm vs. ≥ 50 mm) and breast pCR (OR 0.38, 95% CI 0.15-0.96) were associated with residual LN metastases in the axilla.

CONCLUSIONS

Breast pCR or ITC only in TAD LNs can, with reasonable certainty, preclude more than three positive non-TAD LNs. Additionally, patients with only ITCs in the TAD LN had a low risk of having any non-TAD LN metastases after NACT. De-escalated axillary treatment may be considered in both subgroups.

Social Characteristics and Adherence to Adjuvant Endocrine Therapy in Premenopausal Women With Breast Cancer

PURPOSE

Social characteristics, including cohabitation/marital status and socioeconomic position (SEP)-education level, employment status, and income-influence breast cancer prognosis. We investigated the impact of these social characteristics on adherence to adjuvant endocrine therapy (AET) from treatment initiation to 5 years after diagnosis.

METHODS

We assembled a nationwide, population-based cohort of premenopausal women diagnosed in Denmark with stage I-III, estrogen receptor-positive breast cancer during 2002-2011. We ascertained prediagnostic social characteristics from national registries. AET adherence was based on information from the Danish Breast Cancer Group and operationalized as (1) adherence trajectories (from group-based trajectory modeling) and (2) early discontinuation. We computed odds ratios (ORs) and associated 95% CI to estimate the association of cohabitation and SEP with AET adherence using multinomial and logistic regression models adjusted according to directed acyclic graphs.

RESULTS

Among 4,353 patients, we identified three adherence trajectories-high adherence (57%), slow decline (36%), and rapid decline (6.9%). Compared with cohabiting women, those living alone had higher ORs of slow (1.26 [95% CI, 1.08 to 1.46]) or rapid decline (1.66 [95% CI, 1.27 to 2.18]) versus high adherence. The corresponding ORs for women not working versus employed women were 1.22 (95% CI, 1.02 to 1.45) and 1.76 (95% CI, 1.30 to 2.38). For early discontinuation (17%), the ORs were 1.48 (95% CI, 1.23 to 1.78) for living alone and 1.44 (95% CI, 1.17 to 1.78) for women not working.

CONCLUSION

Adherence to AET was lower among women living alone or unemployed than cohabiting or employed women, respectively. These women may benefit from support programs to enhance AET adherence.

Circulating C-reactive protein levels as a prognostic biomarker in breast cancer across body mass index groups

Obesity and systemic inflammation are associated with breast cancer (BC) outcomes. Systemic inflammation is increased in obesity. We examined the association between C-reactive protein (CRP) and disease-free survival (DFS) and overall survival (OS) overall, and according to body mass index (BMI). We assembled a cohort of women with BC (stage I-III) seen at Aarhus University Hospital between 2010 and 2020 who donated blood at BC diagnosis (N = 2673). CRP levels were measured and divided into quartiles. We followed patients from surgery to recurrence, contralateral BC, other malignancy, death, emigration, or end-of-follow-up. We used Cox regression to estimate hazard ratios (HRs) with 95% confidence intervals (95% CIs) to compare outcomes across CRP quartiles, overall and stratified by BMI (normal-weight (18.5 ≤ BMI < 25 kg/m2), overweight (25 ≤ BMI < 30 kg/m2), and obesity (BMI ≥ 30 kg/m2)). During follow-up, 368 events (212 recurrences, 38 contralateral BCs, and 118 deaths) occurred (median follow-up 5.55 years). For DFS, high CRP (CRP ≥ 3.19 mg/L) was associated with an increased risk of events (HRadj:1.62 [95% CI = 1.14-2.28]). In BMI-stratified analyses, high CRP was associated with elevated risk of events in normal-weight and overweight (HRadj:1.70 [95% CI = 1.09-2.66]; HRadj:1.75 [95% CI = 1.08-2.86]), but in obesity, the estimate was less precise (HRadj:1.73 [95% CI = 0.78-3.83]). For OS, high CRP was associated with increased risk of death (HRadj:2.47 [95% CI = 1.62-3.76]). The association was strong in normal-weight and overweight (HRadj:3.66 [95% CI = 1.95-6.87]; HRadj:1.92 [95% CI = 1.06-3.46]), but less clear in obesity (HRadj:1.40 [95% CI = 0.64-3.09]). To sum up, high CRP levels at BC diagnosis were associated with inferior prognosis in early BC irrespective of BMI, although less clear in patients with obesity.

Population-wide evaluation of artificial intelligence and radiologist assessment of screening mammograms

OBJECTIVES

To validate an AI system for standalone breast cancer detection on an entire screening population in comparison to first-reading breast radiologists.

MATERIALS AND METHODS

All mammography screenings performed between August 4, 2014, and August 15, 2018, in the Region of Southern Denmark with follow-up within 24 months were eligible. Screenings were assessed as normal or abnormal by breast radiologists through double reading with arbitration. For an AI decision of normal or abnormal, two AI-score cut-off points were applied by matching at mean sensitivity (AIsens) and specificity (AIspec) of first readers. Accuracy measures were sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and recall rate (RR).

RESULTS

The sample included 249,402 screenings (149,495 women) and 2033 breast cancers (72.6% screen-detected cancers, 27.4% interval cancers). AIsens had lower specificity (97.5% vs 97.7%; p < 0.0001) and PPV (17.5% vs 18.7%; p = 0.01) and a higher RR (3.0% vs 2.8%; p < 0.0001) than first readers. AIspec was comparable to first readers in terms of all accuracy measures. Both AIsens and AIspec detected significantly fewer screen-detected cancers (1166 (AIsens), 1156 (AIspec) vs 1252; p < 0.0001) but found more interval cancers compared to first readers (126 (AIsens), 117 (AIspec) vs 39; p < 0.0001) with varying types of cancers detected across multiple subgroups.

CONCLUSION

Standalone AI can detect breast cancer at an accuracy level equivalent to the standard of first readers when the AI threshold point was matched at first reader specificity. However, AI and first readers detected a different composition of cancers.

CLINICAL RELEVANCE STATEMENT

Replacing first readers with AI with an appropriate cut-off score could be feasible. AI-detected cancers not detected by radiologists suggest a potential increase in the number of cancers detected if AI is implemented to support double reading within screening, although the clinicopathological characteristics of detected cancers would not change significantly.

KEY POINTS

• Standalone AI cancer detection was compared to first readers in a double-read mammography screening population. • Standalone AI matched at first reader specificity showed no statistically significant difference in overall accuracy but detected different cancers. • With an appropriate threshold, AI-integrated screening can increase the number of detected cancers with similar clinicopathological characteristics.

Prognostic Value of Pretreatment Plasma C-Reactive Protein in Patients with Early-Stage Breast Cancer

BACKGROUND

Breast cancer incidence is now the highest among all cancers and accountable for 6.6% of all cancer-related deaths worldwide. Studies of the prognostic utility of plasma C-reactive protein (CRP) measurement in early-stage breast cancer have given discrepant results.

METHODS

We identified 6,942 patients in the Danish Breast Cancer Cooperative Group database with early-stage breast cancer diagnosed between 2002 and 2016 who had a measure of pretreatment plasma CRP. Outcomes were recurrence-free interval and survival for a period up to 10 years. We analyzed associations with plasma CRP using Fine-Gray proportional subdistribution hazards model with recurrence-free interval. Data on plasma CRP were analyzed per doubling of concentration and in relation to CRP levels of <3 mg/L, 3 to 10 mg/L, and >10 mg/L and stratified according to standard clinical parameters in sensitivity analyses.

RESULTS

A doubling of the plasma CRP concentration was associated with increased risk of recurrence (multivariate adjusted HR, 1.05; 95% CI, 1.01-1.08) and shorter survival (HR, 1.13; 95% CI, 1.09-1.16) in multivariate analyses. Survival was shorter in patients with plasma CRP levels of 3 to 10 and >10 mg/L versus <3 mg/L, with multivariate adjusted HRs of 1.30; 95% CI, 1.17-1.45 and 1.65; 95% CI, 1.39-1.95, respectively.

CONCLUSIONS

Elevated plasma CRP measured before treatment in patients with early-stage breast cancer is an independent biomarker of increased risk of recurrence and early death.

IMPACT

CRP measures before treatment might be used to individualize follow-up of patients with early-stage breast cancer.

Evaluating Danish Breast Cancer Group locoregional radiotherapy guideline adherence in clinical treatment data 2008-2016: The DBCG RT Nation study

BACKGROUND AND PURPOSE

Guideline adherence in radiotherapy is crucial for maintaining treatment quality and consistency, particularly in non-trial patient settings where most treatments occur. The study aimed to assess the impact of guideline changes on treatment planning practices and compare manual registry data accuracy with treatment planning data.

MATERIALS AND METHODS

This study utilised the DBCG RT Nation cohort, a collection of breast cancer radiotherapy data in Denmark, to evaluate adherence to guidelines from 2008 to 2016. The cohort included 7448 high-risk breast cancer patients. National guideline changes included, fractionation, introduction of respiratory gating, irradiation of the internal mammary lymph nodes, use of the simultaneous integrated boost technique and inclusion of the Left Anterior Descending coronary artery in delineation practice. Methods for structure name mapping, laterality detection, detection of temporal changes in population mean lung volume, and dose evaluation were presented and applied. Manually registered treatment characteristic data was obtained from the Danish Breast Cancer Database for comparison.

RESULTS

The study found immediate and consistent adherence to guideline changes across Danish radiotherapy centres. Treatment practices before guideline implementation were documented and showed a variation among centres. Discrepancies between manual registry data and actual treatment planning data were as high as 10% for some measures.

CONCLUSION

National guideline changes could be detected in the routine treatment data, with a high degree of compliance and short implementation time. Data extracted from treatment planning data files provides a more accurate and detailed characterisation of treatments and guideline adherence than medical register data.

Social characteristics and social benefit use among premenopausal breast cancer survivors in Denmark: a population-based cohort study

PURPOSE

In 2020, one million women aged < 55 years were diagnosed with breast cancer globally. The impact of breast cancer and its treatments on these women's ability to work and need for social benefits may differ by social characteristics. We evaluated social benefit use following breast cancer by education and cohabitation.

METHODS

We conducted a nationwide population-based cohort study, including women aged 18-55 years diagnosed with stage I-III breast cancer in Denmark during 2002-2011. Statistics Denmark provided information on cohabitation, education, and social benefit use from 1 year pre-diagnosis to 10 years post-diagnosis. We calculated weekly proportions of self-support, unemployment, disability pension, flexi jobs, and sick leave according to education and cohabitation.

RESULTS

Of 5345 women, 81.8% were self-supporting, 4.5% received disability pensions, 1.6% had flexi jobs, 3.6% were on sick leave, and 5.5% were unemployed 1 year pre-diagnosis. Ten years post-diagnosis, the proportions were 69.0%, 13.0%, 10.5%, 3.4%, and 2.0% of 3663 survivors. Disability pensions and flexi jobs increased from 12.1 to 26.4% and 2.8 to 13.5% in women with short education, from 4.1 to 12.8% and 1.8 to 12.2% in women with medium education, and from 0.8 to 6.0% and 0.9 to 6.9% in longer educated. Disability pensions increased more in women living alone (7.8 to 19.9%), than in cohabiting women (3.6 to 11.3%).

CONCLUSIONS

Use of social benefits reflecting lost ability to work was highest in less educated women and in women living alone.

IMPLICATIONS FOR CANCER SURVIVORS

Awareness of these groups is crucial when tailoring efforts to support work participation in cancer survivors.

Clinical factors associated with patterns of endocrine therapy adherence in premenopausal breast cancer patients

INTRODUCTION

Patients with hormone receptor positive breast cancer are recommended at least five years of adjuvant endocrine therapy, but adherence to this treatment is often suboptimal. We investigated longitudinal trends in adjuvant endocrine therapy (AET) adherence among premenopausal breast cancer patients and identified clinical characteristics, including baseline comorbidities and non-cancer chronic medication use, associated with AET adherence.

METHODS

We included stage I-III premenopausal breast cancer patients diagnosed during 2002-2011 and registered in the Danish Breast Cancer Group clinical database who initiated AET. We used group-based trajectory modeling to describe AET adherence patterns. We also linked patients to Danish population-based registries and fit multinomial logistic models to compute odds ratios (ORs) and 95% confidence intervals (95% CIs) associating clinical characteristics with AET adherence patterns.

RESULTS

We identified three adherence patterns among 4,353 women-high adherers (57%), slow decliners (36%), and rapid decliners (6.9%). Women with stage I disease (vs. stage II; OR: 1.9, 95% CI 1.5, 2.5), without chemotherapy (vs. chemotherapy; OR: 4.3, 95% CI 3.0, 6.1), with prevalent comorbid disease (Charlson Comorbidity Index score ≥ 1 vs. 0; OR: 1.6, 95% CI 1.1, 2.3), and with a history of chronic non-cancer medication use (vs. none; OR: 1.3, 95% CI 1.0, 1.8) were more likely to be rapid decliners compared with high adherers.

CONCLUSIONS

Women with stage I cancer, no chemotherapy, higher comorbidity burden, and history of chronic non-cancer medication use were less likely to adhere to AET. Taking steps to promote adherence in these groups of women may reduce their risk of recurrence.

Validation of primary and outcome data quality in a Swedish population-based breast cancer quality registry

BACKGROUND

Population-based cancer quality registries are of great importance for the improvement of cancer care. However, little is known about the quality of recurrence data in cancer quality registries. The aim of this study was to evaluate data quality in the regional Breast Cancer Quality Registry of Central Sweden, with emphasis on the validity of recorded information on recurrence.

METHODS

Validation by re-abstraction was performed on a random sample of 800 women with primary invasive breast cancer stage I-III diagnosed between 1993 and 2010, of which 400 had at least one registered recurrence and 400 had no registered recurrence. Registry data were compared with data from medical records. Exact agreement, correlation and kappa values, sensitivity and specificity were calculated.

RESULTS

Seven hundred forty-seven women (93%) were available for analysis. Exact agreement was high for diagnostics, tumor characteristics, surgery, and adjuvant oncological treatment (90% or more for most variables). The registry's sensitivity was low for regional recurrence (47%), but higher for local and distant recurrence (80% and 75%), whereas specificity was overall high (≥ 95%). Combining all recurrence categories irrespective of localization improved sensitivity to 90% with a specificity of 91%. In 87% of women, the date of first recurrence according to medical records fell within ± 90 days of the date recorded in the registry.

CONCLUSIONS

While the quality of data in the regional Breast Cancer Quality Registry was generally high, data accuracy on recurrences was lower. The overall precision of identifying any recurrence, irrespective of localization, was high. However, the accuracy of classification of recurrences (local, regional or distant) was lower, with evidence of underreporting for each of the recurrence categories. Given the importance of recurrence-related outcomes in the assessment of quality of care, efforts should be made to improve the reporting of recurrences.

Impact of type 2 diabetes on complications after primary breast cancer surgery: Danish population-based cohort study

BACKGROUND

Knowledge is sparse on the impact of type 2 diabetes (T2D) on surgical outcomes after breast cancer surgery. This study investigated the association between T2D and risk of complications after primary breast cancer surgery, and evaluated the biological interaction between T2D and co-morbidities.

METHODS

Using the Danish Breast Cancer Group clinical database, a cohort of all Danish women diagnosed with early-stage breast cancer during 1996-2022 was created. All patients underwent mastectomy or breast-conserving surgery. Information on prevalent T2D was collected from Danish medical and prescription registries. Surgical complications were defined as hospital diagnoses for medical or surgical complications developing within 30 days after primary breast cancer surgery. The 30-day cumulative incidence proportion of complications was calculated, and Cox regression was used to estimate HRs. Interaction contrasts were computed to determine the additive interaction between T2D and co-morbidities on the incidence rate of complications.

RESULTS

Among 98 589 women with breast cancer, 6332 (6.4%) had T2D at breast cancer surgery. Overall, 1038 (16.4%) and 9861 (10.7%) women with and without T2D developed surgical complications, yielding cumulative incidence proportions of 16 (95% c.i. 15 to 17) and 11 (10 to 11)% respectively, and a HR of 1.43 (95% c.i. 1.34 to 1.53). The incidence rate of surgical complications explained by the interaction of T2D with moderate and severe co-morbidity was 21 and 42%, respectively.

CONCLUSION

Women with breast cancer and T2D had a higher risk of complications after primary breast cancer surgery than those without T2D. A synergistic effect of T2D and co-morbidity on surgical complications can explain this association.

Early life body size and puberty markers as predictors of breast cancer risk later in life: A neural network analysis

BACKGROUND

The early life factors of birthweight, child weight, height, body mass index (BMI) and pubertal timing are associated with risks of breast cancer. However, the predictive value of these factors in relation to breast cancer is largely unknown. Therefore, using a machine learning approach, we examined whether birthweight, childhood weights, heights, BMIs, and pubertal timing individually and in combination were predictive of breast cancer.

METHODS

We used information on birthweight, childhood height and weight, and pubertal timing assessed by the onset of the growth spurt (OGS) from 164,216 girls born 1930-1996 from the Copenhagen School Health Records Register. Of these, 10,002 women were diagnosed with breast cancer during 1977-2019 according to a nationwide breast cancer database. We developed a feed-forward neural network, which was trained and tested on early life body size measures individually and in various combinations. Evaluation metrics were examined to identify the best performing model.

RESULTS

The highest area under the receiver operating curve (AUC) was achieved in a model that included birthweight, childhood heights, weights and age at OGS (AUC = 0.600). A model based on childhood heights and weights had a comparable AUC value (AUC = 0.598), whereas a model including only childhood heights had the lowest AUC value (AUC = 0.572). The sensitivity of the models ranged from 0.698 to 0.760 while the precision ranged from 0.071 to 0.076.

CONCLUSION

We found that the best performing network was based on birthweight, childhood weights, heights and age at OGS as the input features. Nonetheless, this performance was only slightly better than the model including childhood heights and weights. Further, although the performance of our networks was relatively low, it was similar to those from previous studies including well-established risk factors. As such, our results suggest that childhood body size may add additional value to breast cancer prediction models.

Breast cancer detection accuracy of AI in an entire screening population: a retrospective, multicentre study

BACKGROUND

Artificial intelligence (AI) systems are proposed as a replacement of the first reader in double reading within mammography screening. We aimed to assess cancer detection accuracy of an AI system in a Danish screening population.

METHODS

We retrieved a consecutive screening cohort from the Region of Southern Denmark including all participating women between Aug 4, 2014, and August 15, 2018. Screening mammograms were processed by a commercial AI system and detection accuracy was evaluated in two scenarios, Standalone AI and AI-integrated screening replacing first reader, with first reader and double reading with arbitration (combined reading) as comparators, respectively. Two AI-score cut-off points were applied by matching at mean first reader sensitivity (AIsens) and specificity (AIspec). Reference standard was histopathology-proven breast cancer or cancer-free follow-up within 24 months. Coprimary endpoints were sensitivity and specificity, and secondary endpoints were positive predictive value (PPV), negative predictive value (NPV), recall rate, and arbitration rate. Accuracy estimates were calculated using McNemar's test or exact binomial test.

RESULTS

Out of 272,008 screening mammograms from 158,732 women, 257,671 (94.7%) with adequate image data were included in the final analyses. Sensitivity and specificity were 63.7% (95% CI 61.6%-65.8%) and 97.8% (97.7-97.8%) for first reader, and 73.9% (72.0-75.8%) and 97.9% (97.9-98.0%) for combined reading, respectively. Standalone AIsens showed a lower specificity (-1.3%) and PPV (-6.1%), and a higher recall rate (+ 1.3%) compared to first reader (p < 0.0001 for all), while Standalone AIspec had a lower sensitivity (-5.1%; p < 0.0001), PPV (-1.3%; p = 0.01) and NPV (-0.04%; p = 0.0002). Compared to combined reading, Integrated AIsens achieved higher sensitivity (+ 2.3%; p = 0.0004), but lower specificity (-0.6%) and PPV (-3.9%) as well as higher recall rate (+ 0.6%) and arbitration rate (+ 2.2%; p < 0.0001 for all). Integrated AIspec showed no significant difference in any outcome measures apart from a slightly higher arbitration rate (p < 0.0001). Subgroup analyses showed higher detection of interval cancers by Standalone AI and Integrated AI at both thresholds (p < 0.0001 for all) with a varying composition of detected cancers across multiple subgroups of tumour characteristics.

CONCLUSIONS

Replacing first reader in double reading with an AI could be feasible but choosing an appropriate AI threshold is crucial to maintaining cancer detection accuracy and workload.

Trajectories of body mass index across the lifecourse and associations with post-menopausal breast cancer by estrogen receptor status

BACKGROUND

Associations between a high body mass index (BMI) at single timepoints during child- and adulthood and risks of post-menopausal breast cancer are well-established, but associations with BMI across the lifecourse remains largely unknown. Therefore, we examined whether lifecourse BMI trajectories were associated with risks of post-menopausal breast cancer overall and by estrogen receptor (ER) status.

METHODS

We included 6698 Danish women born 1930-1946. Information on BMI at ages 6-15 years came from the Copenhagen School Health Records Register, and information on BMI at ages 20, 30, 40, 50 and/or 50-64 years came from the Diet, Cancer and Health cohort. Breast cancer cases (n = 577) were identified in the Danish Breast Cancer Cooperative Group database. Six BMI trajectories were identified using latent class trajectory modelling. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox regression models.

RESULTS

Compared to women with a trajectory characterized by an average BMI gain across life, women with the two trajectories with steep increases in BMI during childhood and adolescence that thereafter largely stabilized, had lower risks of post-menopausal breast cancer and ER-positive tumors. The adjusted HRs for ER-positive tumors were 0.67 (95% CI: 0.47-0.95) and 0.68 (95% CI: 0.46-1.01), respectively. In contrast, women with a trajectory with a low gain in BMI during childhood and adolescence followed by a subsequent steep increase during adulthood, had higher risks of post-menopausal breast cancer and ER-positive tumors when compared to women with an average BMI gain. The adjusted HR for ER-positive tumors was 1.28 (95% CI: 0.98-1.67).

CONCLUSIONS

Our findings suggest that the timing of excess gain in BMI across the lifecourse impacts subsequent post-menopausal breast cancer risks. Thus, the BMI development across life is likely useful in the identification of women at increased risks of post-menopausal breast cancer.

Diagnosis and treatment of breast cancer in Denmark during the COVID-19 pandemic: a nationwide population-based study

BACKGROUND

The COVID-19 pandemic was a global health crisis with population-wide behavioural restrictions imposed worldwide to reduce transmission of infection and to limit the potential burden on the healthcare systems. We examined whether there was any change in the diagnosis or treatment of breast cancer during the pandemic as compared to previous years.

MATERIAL AND METHODS

The study population comprised all women aged ≥18 years diagnosed with breast cancer in 2015-2021 with data obtained from the clinical quality registry of the Danish Breast Cancer Cooperative Group (DBCG). Data on socioeconomic factors were retrieved from Statistics Denmark. Prevalence ratios (PR) with 95% confidence intervals (CI) were estimated from a generalised linear model (GLM) with a log link for the Poisson family with robust standard errors (SE) of each outcome, using the COVID-19 pandemic period in Denmark as the exposure of interest.

RESULTS

In total, 30,598 breast cancers were diagnosed during the study period. There was a small decrease (4.5%) in the total number of breast cancer cases in 2020 compared with previous years. During the pandemic, a lower proportion of the patients diagnosed with breast cancer had a short educational level (28.5 vs. 26.9%; PR = 0.91; 95% CI: 0.88-0.95), a low income (20.5 vs. 19.0%; PR = 0.90; 0.85-0.95) and fewer than expected in the age group 60-69 years (27.8 vs. 25.3; PR = 0.90; 0.86-0.94) were diagnosed, as compared with the pre-pandemic period. No difference in type of surgery or tumour size was observed. A higher proportion of patients received neo-adjuvant chemotherapy (49.0 vs 55.0%; PR = 1.15; 1.06-1.24), whereas a lower proportion received adjuvant chemotherapy (93.5 vs 85.6%; PR = 0.92; 0.90-0.93) during the pandemic, compared with the pre-pandemic period.

CONCLUSIONS

During the pandemic, a small decrease in the number of breast cancer diagnoses was observed particularly among socially disadvantaged groups. Overall, the quality of breast cancer treatment was maintained.

Social inequality in cancer survivorship: Educational differences in health-related quality of life among 27,857 cancer survivors in Denmark

BACKGROUND

With a growing population of cancer survivors in Denmark, the evaluation of health-related quality of life (HRQoL) has become increasingly important. We describe variations in HRQoL between educational groups in a national population of cancer survivors.

METHODS

We conducted a cross-sectional questionnaire study among breast, prostate, lung, and colon cancer survivors diagnosed in 2010-2019 in Denmark. We used the EORTC QLQ-C30 to assess HRQoL including physical, role, emotional, cognitive, social functioning, and symptoms (fatigue, nausea and vomiting, pain, dyspnea, insomnia, appetite loss, constipation, diarrhea, and financial difficulties). Information on educational level and clinical data were extracted from national registers and clinical databases. Levels of impaired functioning and severe symptoms were identified using newly established thresholds for clinical importance. Multivariate logistic regression was used to examine associations between education and HRQoL. All statistical tests were 2-sided.

RESULTS

In total, 27,857 (42%) participated in the study. Up to 72% and 75% of cancer survivors with short education (≤9 years) reported impaired functioning and severe symptoms, respectively. Cancer survivors with short compared to long education (>12 years) were more likely to report impaired functioning and severe symptoms, with for example significantly higher odds ratios (ORs) for impaired physical function (breast OR = 2.41, 99% CI = 2.01-2.89; prostate OR = 1.81, 99% CI = 1.48-2.21; lung OR = 2.97, 99% CI = 1.95-4.57; and colon cancer OR = 1.69, 99% CI = 1.28-2.24).

CONCLUSIONS

Cancer survivors with short education are at greater risk of impaired HRQoL than survivors with long education 2-12 years after diagnosis. This underscores the need for systematic screening and symptom management in cancer aftercare, in order to reach all cancer survivors, also cancer survivors with short education.

End-to-end framework for automated collection of large multicentre radiotherapy datasets demonstrated in a Danish Breast Cancer Group cohort

Large Digital Imaging and Communications in Medicine (DICOM) datasets are key to support research and the development of machine learning technology in radiotherapy (RT). However, the tools for multi-centre data collection, curation and standardisation are not readily available. Automated batch DICOM export solutions were demonstrated for a multicentre setup. A Python solution, Collaborative DICOM analysis for RT (CORDIAL-RT) was developed for curation, standardisation, and analysis of the collected data. The setup was demonstrated in the DBCG RT-Nation study, where 86% (n = 7748) of treatments in the inclusion period were collected and quality assured, supporting the applicability of the end-to-end framework.

The association between education and fear of recurrence among breast cancer patients in follow-up - and the mediating effect of self-efficacy

BACKGROUND

Major restructuring of surveillance after breast cancer treatment with less follow-up consultations may result in insecurity and fear of recurrence (FCR) among the less resourceful breast cancer patients. We investigate the association between breast cancer patients' education and FCR and if self-efficacy mediates the associations between education and FCR.

MATERIAL AND METHODS

A questionnaire survey was conducted from 2017 to 2019, among 1773 breast cancer patients shortly after having their follow-up switched from regular outpatient visits with an oncologist to either nurse-led or patient-initiated follow-up, with a subsequent questionnaire after 12 months. Data on disease and treatment characteristics were extracted from medical records and the Danish Breast Cancer Group Database. Logistic regression analyses were used to examine the association between education and FCR. Separate analyses were conducted for patients ≤ and >5 years since diagnosis and all models were adjusted for age and cohabitation status. To explore potential mediation by self-efficacy, we conducted regression analyses on education and FCR further adjusting for self-efficacy.

RESULTS

The participation rate was 57%, and after the exclusion of patients due to missing data, 917 were included in analyses. Patients with long education had significantly less FCR compared to patients with short education (OR (95% CI) 0.71 (0.51;0,99)). When separated by time since diagnosis, there was no association among patients >5 years since diagnosis while the OR was 0.51 (95% CI, 0.30;0.85) for patients ≤5 years since diagnosis. Further adjusting for self-efficacy among patients <5 years since diagnosis resulted in an OR of 0.56 (95% CI, 0.33;0.95) among patients with long compared to short education.

CONCLUSION

Up to 5 years after diagnosis, breast cancer patients with long education are less likely to experience FCR than patients with short education. Self-efficacy mediated only a very small part of this association, indicating that other factors play a role in socioeconomic differences in FCR among breast cancer patients.

Educational differences in healthcare use among survivors after breast, prostate, lung, and colon cancer - a SEQUEL cohort study

BACKGROUND

Many cancer survivors experience late effects after cancer. Comorbidity, health literacy, late effects, and help-seeking behavior may affect healthcare use and may differ among socioeconomic groups. We examined healthcare use among cancer survivors, compared with cancer-free individuals, and investigated educational differences in healthcare use among cancer survivors.

METHODS

A Danish cohort of 127,472 breast, prostate, lung, and colon cancer survivors from the national cancer databases, and 637,258 age- and sex-matched cancer-free individuals was established. Date of entry was 12 months after diagnosis/index date (for cancer-free individuals). Follow-up ended at death, emigration, new primary cancer, December 31st, 2018, or up to 10 years. Information about education and healthcare use, defined as the number of consultations with general practitioner (GP), private practicing specialists (PPS), hospital, and acute healthcare contacts 1-9 years after diagnosis/index date, was extracted from national registers. We used Poisson regression models to compare healthcare use between cancer survivors and cancer-free individuals, and to investigate the association between education and healthcare use among cancer survivors.

RESULTS

Cancer survivors had more GP, hospital, and acute healthcare contacts than cancer-free individuals, while the use of PPS were alike. One-to-four-year survivors with short compared to long education had more GP consultations (breast, rate ratios (RR) = 1.28, 95% CI = 1.25-1.30; prostate, RR = 1.14, 95% CI = 1.10-1.18; lung, RR = 1.18, 95% CI = 1.13-1.23; and colon cancer, RR = 1.17, 95% CI = 1.13-1.22) and acute contacts (breast, RR = 1.35, 95% CI = 1.26-1.45; prostate, RR = 1.26, 95% CI = 1.15-1.38; lung, RR = 1.24, 95% CI = 1.16-1.33; and colon cancer, RR = 1.35, 95% CI = 1.14-1.60), even after adjusting for comorbidity. One-to-four-year survivors with short compared to long education had less consultations with PPS, while no association was observed for hospital contacts.

CONCLUSION

Cancer survivors used more healthcare than cancer-free individuals. Cancer survivors with short education had more GP and acute healthcare contacts than survivors with long education. To optimize healthcare use after cancer, we need to better understand survivors' healthcare-seeking behaviors and their specific needs, especially among survivors with short education.

Effects on long-term survival of psychosocial group intervention in early-stage breast cancer: follow-up of a randomized controlled trial

BACKGROUND

The promise of prolonged survival after psychosocial interventions has long been studied, but not convincingly demonstrated. This study aims to investigate whether a psychosocial group intervention improved long-term survival in women with early-stage breast cancer and investigate differences in baseline characteristics and survival between study participants and non-participants.

METHODS

A total of 201 patients were randomized to two six-hour psychoeducation sessions and eight weekly sessions of group psychotherapy or care as usual. Additionally, 151 eligible patients declined to participate. Eligible patients were diagnosed and treated at Herlev Hospital, Denmark, and followed for vital status up to 18 years after their primary surgical treatment. Cox's proportional hazard regressions were used to estimate hazard ratios (HRs) for survival.

RESULTS

The intervention did not significantly improve survival in the intervention group compared with the control group (HR, 0.68; 95% confidence interval (CI), 0.41-1.14). Participants and non-participants differed significantly in age, cancer stage, adjuvant chemotherapy, and crude survival. When adjusted, no significant survival difference between participants and non-participants remained (HR, 0.77; 95% CI, 0.53-1.11).

CONCLUSIONS

We could not show improved long-term survival after the psychosocial intervention. Participants survived longer than nonparticipants, but clinical and demographic characteristics, rather than study participation, seem accountable for this difference.

Surgical-site infection is associated with increased risk of breast cancer-related lymphedema: A nationwide cohort study

BACKGROUND

Surgical-site infection (SSI) is one of the most common short-term complications following breast cancer treatment and can inhibit lymphatic drainage. It is currently not known whether SSI increases the risk of long-term breast cancer-related lymphedema (BCRL). Thus, the objective of this study was to examine the association between surgical-site infection and the risk of BCRL METHODS: This nationwide study identified all patients treated for unilateral, primary invasive, nonmetastatic breast cancer in Denmark between January 1, 2007, and December 31, 2016 (n = 37,937). A redemption of antibiotics after breast cancer treatment was used as a disease proxy for SSI, included as a time-varying exposure. The risk of BCRL was analyzed up to 3 years after breast cancer treatment using multivariate Cox regression and adjusted for cancer treatment, demographics, comorbidities, and socioeconomic variables.

RESULTS

There were 10,368 (27.33%) patients with a SSI and 27,569 (72.67%) without a SSI (incidence rate per 100 patients, 33.10 (95%CI, 32.47-33.75). The BCRL incidence rate per 100 person-years for patients with SSI was 6.72 (95%CI: 6.41-7.05) and 4.86 (95%CI: 4.70-5.02) for patients without an SSI. There was an overall significant increased risk of BCRL in patients with an SSI (adjusted HR, 1.11; 95%CI: 1.04-1.17), with the highest risk 3 years after breast cancer treatment (adjusted HR, 1.28; 95%CI: 1.08-1.51) CONCLUSION: This large nationwide cohort study showed that SSI was associated with an overall 10% increased risk of BCRL. These findings may be used to identify patients at high risk of BCRL that would benefit from enhanced BCRL surveillance.

Ovarian removal and subsequent breast cancer prognosis: a nationwide cohort study

PURPOSE

To evaluate whether previous ovarian removal concomitant with benign hysterectomy improves prognosis in a cohort of women with breast cancer.

METHODS

In this nationwide register-based cohort study, risk of recurrence and mortality were examined in 4563 women with invasive breast cancer and previous bilateral salpingo-oophorectomy (BSO) concomitant with benign hysterectomy, during 1977-2018. Comparing with benign hysterectomy alone, hazard ratios (HRs) and 95% confidence intervals (CIs) were evaluated by Cox-proportional hazards regression models. Analyses were stratified on age at hysterectomy as a proxy for menopausal status (< 45, 45-54 and ≥ 55 years); tumor characteristics, estrogen receptor (ER)-status, and use of hormone therapy (HT) were included in multivariable models.

RESULTS

Compared with hysterectomy alone, premenopausal (< 45 years) BSO at benign hysterectomy was associated with an age and calendar period adjusted HR of 1.48 (95% CI 0.83-2.65) for breast cancer recurrence within 10 years of follow-up, a HR of 1.07 (95% CI 0.66-1.72) for overall mortality after breast cancer, and a HR of 0.59 (95% CI 0.26-1.32) for breast cancer-specific mortality. The corresponding HRs for postmenopausal (≥ 55 years) BSO at benign hysterectomy were 1.51 (95% CI 0.73-3.12) for recurrences, 1.34 (95% CI 0.74-2.44) for overall mortality, and 1.78 (95% CI 0.74-4.30) for breast cancer mortality. Adjusting for tumor characteristics, ER-status and HT did not alter the results.

CONCLUSION

Results from this cohort study did not indicate an improvement in breast cancer prognosis when removing the ovaries at benign hysterectomy prior to the cancer diagnosis.

Unplanned cancer presentation in patients with psychiatric disorders: A nationwide register-based cohort study in Denmark

Unplanned presentation in the cancer pathway is more common in patients with psychiatric disorders than in patients without. More knowledge about the risk factors for unplanned presentation could help target interventions to ensure earlier diagnosis of cancer in patients with psychiatric disorders. This study aims to estimate the association between patient characteristics (social characteristics and coexisting physical morbidity) and cancer diagnosis following unplanned presentation among cancer patients with psychiatric disorders. We conducted a population-based register study including patients diagnosed with cancer in 2014-2018 and also registered with at least one psychiatric disorder in the included Danish registers (n = 26,005). We used logistic regression to assess patient characteristics associated with an unplanned presentation. Almost one in four symptomatic patients (23.6 %) with pre-existing psychiatric disorders presented unplanned in the cancer trajectory. Unplanned presentation was most common for severe psychiatric disorders, e.g. organic disorders and schizophrenia. Old age, male sex, living alone, low education, physical comorbidity, and non-attendance in primary care were associated with increased odds of unplanned presentation. In conclusion, several characteristics of patients with pre-existing psychiatric disorders were associated with unplanned presentation in the cancer trajectory; for some groups more than 40 % had an unplanned presentation. This information could be used to design targeted interventions for patients with pre-existing psychiatric disorders to ensure earlier diagnosis of cancer in this population.

Electronic patient-reported outcome measures to enable systematic follow-up in treatment and care of women diagnosed with breast cancer: a feasibility study protocol

INTRODUCTION

The use of patient-reported outcome measures (PROMs) in clinical practice has the potential to promote person-centred care and improve patients' health-related quality of life. We aimed to develop an intervention centred around electronic PROMs (ePROMs) for systematic follow-up in patients diagnosed with breast cancer and to evaluate its feasibility.

METHODS AND ANALYSIS

We developed a nurse-oriented and surgeon-oriented intervention in PROMs, including (1) an education programme for nurses and surgeons; (2) administration of BREAST-Q as proactive ePROMs during follow-up in patients diagnosed with breast cancer and (3) feedback to nurses and surgeons on PROM scores and a guidance manual for healthcare practitioners. Subsequently, we designed a non-controlled feasibility evaluation on the outcomes acceptability, demand, implementation, practicality and integration. The feasibility evaluation includes qualitative ethnographic studies exploring the user perspectives of patients, nurses and surgeons and quantitative studies to explore the characteristics of the patient population regarding demographic background, response rates and response patterns. The feasibility study was initiated in September 2021, will continue until 2024 and will include approximately 900 patients. EPROMs are collected at the following assessment time points: baseline (after diagnosis, before surgery), 1-year follow-up and 3-year endpoint.

ETHICS AND DISSEMINATION

The study will be conducted according to the General Data Protection Regulation and the fifth version of the Helsinki Declaration. The National Committee on Health Research Ethics approved the study according to the law of the Committee § 1, part 4. All data will be anonymised before its publication. The results of the feasibility study will be published in peer-reviewed, international journals.

Birthweight, childhood body size, and timing of puberty and risks of breast cancer by menopausal status and tumor receptor subtypes

Background

Associations of birthweight, childhood body size and pubertal timing with breast cancer risks by menopausal status and tumor receptor subtypes are inconclusive. Thus, we investigated these associations in a population-based cohort of Danish women.

Methods

We studied 162,419 women born between 1930 and 1996 from the Copenhagen School Health Records Register. The register includes information on birthweight, measured childhood weights and heights at the age of 7–13 years, and computed ages at the onset of the growth spurt (OGS) and at peak height velocity (PHV). The Danish Breast Cancer Cooperative Group database provided information on breast cancer (n = 7510), including estrogen receptor (ER), human epidermal growth factor receptor 2 (HER2) and menopausal status. Hormone replacement therapy use came from the Danish National Prescription Registry. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated by Cox regression.

Results

We found that birthweight was not associated with any breast cancer subtypes. While childhood BMI was not statistically significantly associated with ER+ tumors nor consistently with ER− tumors among pre-menopausal women, consistent inverse associations were found among postmenopausal women. At the age of 7 years, the HRs for postmenopausal ER+ and ER− tumors were 0.90 (95% CI 0.87–0.93) and 0.84 (95% CI 0.79–0.91) per BMI z-score, respectively. Similarly, childhood BMI was inversely associated with pre- and postmenopausal HER2− tumors, but not with HER2+ tumors. Childhood height was positively associated with both pre- and postmenopausal ER+ tumors, but not with ER− tumors. At the age of 7 years, the HRs for postmenopausal ER+ and ER− tumors were 1.09 (95% CI 1.06–1.12) and 1.02 (95% CI 0.96–1.09) per height z-score, respectively. In general, childhood height was positively associated with HER2+ and HER2− tumors among pre- and postmenopausal women. Ages at OGS and PHV were not associated with any breast cancer subtypes.

Conclusions

We showed that a high BMI and short stature in childhood are associated with reduced risks of certain breast cancer subtypes. Thus, childhood body composition may play a role in the development of breast cancer.

Systemic or Vaginal Hormone Therapy After Early Breast Cancer: A Danish Observational Cohort Study

BACKGROUND

Women treated for breast cancer (BC) often suffer genitourinary syndrome of menopause. These symptoms may be alleviated by vaginal estrogen therapy (VET) or menopausal hormone therapy (MHT). However, there are concerns of risks of recurrence of BC and death following treatment.

METHODS

Our study included longitudinal data from a national cohort of postmenopausal women, diagnosed 1997-2004 with early-stage invasive estrogen receptor-positive nonmetastatic BC, who received no treatment or 5 years of adjuvant endocrine therapy. We ascertained prescription data on hormone therapy, VET or MHT, from a national prescription registry. We evaluated mortality and risk of recurrence associated with use of VET and MHT vs non-use using multivariable models adjusted for potential confounders.

RESULTS

Among 8461 women who had not received VET or MHT before BC diagnosis, 1957 and 133 used VET and MHT, respectively, after diagnosis. Median follow-up was 9.8 years for recurrence and 15.2 years for mortality. The adjusted relative risk of recurrence was 1.08 (95% confidence interval [CI] = 0.89 to 1.32) for VET (1.39 [95% CI = 1.04 to 1.85 in the subgroup receiving adjuvant aromatase inhibitors]) and 1.05 (95% CI = 0.62 to 1.78) for MHT. The adjusted hazard ratios for overall mortality were 0.78 (95% CI = 0.71 to 0.87) and 0.94 (95% CI = 0.70 to 1.26) for VET and MHT, respectively.

CONCLUSIONS

In postmenopausal women treated for early-stage estrogen receptor-positive BC, neither VET nor MHT was associated with increased risk of recurrence or mortality. A subgroup analysis revealed an increased risk of recurrence, but not mortality, in patients receiving VET with adjuvant aromatase inhibitors.

Assessing how routes to diagnosis vary by the age of patients with cancer: a nationwide register-based cohort study in Denmark

BACKGROUND

Older patients with cancer have poorer prognosis compared to younger patients. Moreover, prognosis is related to how cancer is identified, and where in the healthcare system patients present, i.e. routes to diagnosis (RtD). We investigated whether RtD varied by patients' age.

METHODS

This population-based national cohort study used Danish registry data. Patients were categorized into age groups and eight mutually exclusive RtD. We employed multinomial logistic regressions adjusted for sex, region, diagnosis year, cohabitation, education, income, immigration status and comorbidities. Screened and non-screened patients were analysed separately.

RESULTS

The study included 137,876 patients. Both younger and older patients with cancer were less likely to get diagnosed after a cancer patient pathways referral from primary care physician compared to middle-aged patients. Older patients were more likely to get diagnosed via unplanned admission, death certificate only, and outpatient admission compared to younger patients. The patterns were similar across comorbidity levels.

CONCLUSIONS

RtD varied by age groups, and middle-aged patients were the most likely to get diagnosed after cancer patient pathways with referral from primary care. Emphasis should be put on raising clinicians' awareness of cancer being the underlying cause of symptoms in both younger patients and in older patients.

The French Early Breast Cancer Cohort (FRESH): A Resource for Breast Cancer Research and Evaluations of Oncology Practices Based on the French National Healthcare System Database (SNDS)

Simple Summary

Because of an important disparity of care pathways and quality of care among women diagnosed with an early-stage breast cancer, we aimed to create a unique cohort of patients including all French women aged 18 years or over, treated by surgery and registered in the general health insurance coverage plan. After aggregating and annotating medico-administrative data on 235,368 early breast cancer patients, we open up perspectives for research on adverse effects, morbidity, mortality, the monitoring of care consumption, or medical-economic studies. We describe data sources, inclusion, and exclusion criteria, basic descriptive analyses, and longitudinal trends over time.

Abstract

Background: Breast cancer (BC) is the most frequent cancer and the leading cause of cancer-related death in women. The French National Cancer Institute has created a national cancer cohort to promote cancer research and improve our understanding of cancer using the National Health Data System (SNDS) and amalgamating all cancer sites. So far, no detailed separate data are available for early BC. Objectives: To describe the creation of the French Early Breast Cancer Cohort (FRESH). Methods: All French women aged 18 years or over, with early-stage BC newly diagnosed between 1 January 2011 and 31 December 2017, treated by surgery, and registered in the general health insurance coverage plan were included in the cohort. Patients with suspected locoregional or distant metastases at diagnosis were excluded. BC treatments (surgery, chemotherapy, targeted therapy, radiotherapy, and endocrine therapy), and diagnostic procedures (biopsy, cytology, and imaging) were extracted from hospital discharge reports, outpatient care notes, or pharmacy drug delivery data. The BC subtype was inferred from the treatments received. Results: We included 235,368 patients with early BC in the cohort (median age: 60 years). The BC subtype distribution was as follows: luminal (80.2%), triple-negative (TNBC, 9.5%); HER2⁺ (10.3%), or unidentifiable (n = 44,388, 18.9% of the cohort). Most patients underwent radiotherapy (n = 200,685, 85.3%) and endocrine therapy (n = 165,655, 70.4%), and 38.3% (n = 90,252) received chemotherapy. Treatments and care pathways are described. Conclusions: The FRESH Cohort is an unprecedented population-based resource facilitating future large-scale real-life studies aiming to improve care pathways and quality of care for BC patients.

Use of beta-blockers and risk of contralateral breast cancer

Beta-blockers have shown antineoplastic effects in laboratory studies but epidemiologic evidence in relation to contralateral breast cancer (CBC) is sparse. We investigated postdiagnosis beta-blocker use and risk of CBC in a cohort of 52 723 women with breast cancer by using nationwide Danish health registers and the Danish Breast Cancer Group database. We defined postdiagnosis beta-blocker use as a time-varying covariate starting 1 year after a second prescription was redeemed. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for CBC associated with beta-blocker use compared to nonuse. We identified 1444 women with CBC of whom 209 women were beta-blocker users. We found an overall HR of 1.08 (95% CI: 0.93-1.27) for beta-blocker use and risk of CBC with no substantial variation according to cumulative amount, intensity or selectivity of beta-blocker use. Hence, our cohort study of women with breast cancer did not sustain a protective effect of beta-blocker use on risk of CBC, irrespective of beta-blocker type.

Mortality After Late Breast Cancer Recurrence in Denmark

PURPOSE

Late breast cancer (BC) recurrence (ie, ≥ 10 years after primary diagnosis) may have a more favorable prognosis than earlier recurrence. We investigated the risk of BC death after late recurrence, identified prognostic factors, and compared survival after early and late recurrence.

METHODS

Using the Danish Breast Cancer Group and other nationwide databases, we identified women with early or late BC recurrence during 2004-2018, who were alive 6 months after recurrence. We followed them until BC death, death from other causes, emigration, 10 years, or December 31, 2018, whichever came first. We calculated mortality rates (MRs) per 1,000 person-years (PY) and cumulative BC mortality, for early versus late recurrence, and by characteristics of the primary tumor and the late recurrence. Using Cox regression, we calculated adjusted hazard ratios (HRs) for BC death, accounting for death from other causes as competing risks.

RESULTS

Among 2,004 patients with late recurrence, 721 died of BC with a median survival time of 10 years (MR = 84.8 per 1,000 PY; 10-year cumulative mortality = 50%). Among 1,528 patients with early recurrence, 1,092 BC deaths occurred with a median survival time of 4 years (MR = 173.9 per 1,000 PY; 10-year cumulative mortality = 72%). We observed a lower hazard of BC-specific death among patients who developed late compared with early recurrence (hazard ratio = 0.72; 95% CI, 0.62 to 0.85). Advanced stage at primary diagnosis, distant metastases, adjuvant treatment for locoregional recurrence, and systemic treatment for distant recurrence were associated with increased mortality after late recurrence. Breast-conserving surgery at primary diagnosis, locoregional recurrence, and surgery for recurrence were associated with lower mortality after late recurrence.

CONCLUSION

Patients with late recurrence had more favorable prognosis than patients with early recurrence. The localization of recurrent disease was the main prognostic factor for BC death.

Routes to cancer diagnosis for patients with pre-existing psychiatric disorders: a nationwide register-based cohort study

Background

Poor cancer prognosis has been observed in patients with pre-existing psychiatric disorders. Therefore, we need better knowledge about the diagnosis of cancer in this patient group. The aim of the study was to describe the routes to cancer diagnosis in patients with pre-existing psychiatric disorders and to analyse how cancer type modified the routes.

Methods

A register-based cohort study was conducted by including patients diagnosed with incident cancer in 2014–2018 (n = 155,851). Information on pre-existing psychiatric disorders was obtained from register data on hospital contacts and prescription medication. Multinomial regression models with marginal means expressed as probabilities were used to assess the association between pre-existing psychiatric disorders and routes to diagnosis.

Results

Compared to patients with no psychiatric disorders, the population with a psychiatric disorder had an 8.0% lower probability of being diagnosed through cancer patient pathways initiated in primary care and a 7.6% higher probability of being diagnosed through unplanned admissions. Patients with pre-existing psychiatric disorders diagnosed with rectal, colon, pancreatic, liver or lung cancer and patients with schizophrenia and organic disorders were less often diagnosed through cancer patient pathways initiated in primary care.

Conclusion

Patients with pre-existing psychiatric disorders were less likely to be diagnosed through Cancer Patient Pathways from primary care. To some extent, this was more pronounced among patients with cancer types that often present with vague or unspecific symptoms and among patients with severe psychiatric disorders. Targeting the routes by which patients with psychiatric disorders are diagnosed, may be one way to improve the prognosis among this group of patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09598-x.

Hypofractionated Whole-Breast Irradiation Focus on Coronary Arteries and Cardiac Toxicity-A Narrative Review

Breast cancer is the most common cancer among women worldwide, which is often treated with radiotherapy. Whole breast irradiation (WBI) is one of the most common types of irradiation. Hypo-fractionated WBI (HF-WBI) reduces the treatment time from 5 to 3 weeks. Recent radiobiological and clinical evidence recommended the use of HF-WBI regardless of the age or stage of disease, and it is proven that hypo-fractionation is non-inferior to conventional fractionation regimen irradiation. However, some studies report an increased incidence of heart-related deaths in the case of breast irradiation by hypo-fractionation, especially in patients with pre-existing cardiac risk factors at the time of treatment. Due to the new technical possibilities of radiotherapy techniques, HF-WBI can reduce the risk of cardiac toxicity by controlling the doses received both by the heart and by the anatomical structures of the heart. The radiobiological “double trouble”, in particular “treble trouble”, for hypo-fractionated regimen scan be avoided by improving the methods of heart sparing based on image-guided irradiation (IGRT) and by using respiration control techniques so that late cardiac toxicity is expected to be limited. However, long-term follow-up of patients treated with HF-WBI with modern radiotherapy techniques is necessary considering the progress of systemic therapy, which is associated with long-term survival, and also the cardiac toxicity of new oncological treatments. The still unknown effects of small doses spread in large volumes on lung tissue may increase the risk of second malignancy, but they can also be indirectly involved in the later development of a heart disease. It is also necessary to develop multivariable radiobiological models that include histological, molecular, clinical, and therapeutic parameters to identify risk groups and dosimetric tolerance in order to limit the incidence of late cardiac events. MR-LINAC will be able to offer a new standard for reducing cardiac toxicity in the future, especially in neoadjuvant settings for small tumors.

Tumour-infiltrating CD4-, CD8- and FOXP3-positive immune cells as predictive markers of mortality in BRCA1- and BRCA2-associated breast cancer

BACKGROUND

The prognostic value of tumour-infiltrating lymphocytes (TILs) in breast cancer is well-established. However, the investigation of specific T-cell subsets exclusively in BRCA-associated breast cancer is sparse.

METHODS

Tumour tissues from 414 BRCA-mutated breast cancer patients were analysed by immunohistochemistry and digital image analysis for expression of CD4, CD8 and FOXP3 immune markers. Distribution of CD4-, CD8- and FOXP3-positive cells and clinicopathological characteristics were assessed according to groups of low or high expression. The prognostic value was evaluated as continuous variables in univariate and multivariate analyses of overall survival and disease-free survival.

RESULTS

Both CD4 and CD8 expression are associated with histological diagnosis, tumour grade and oestrogen and progesterone receptor expression status. CD4 expression is associated with BRCA gene status. A high percentage of tumour-infiltrating CD4-, CD8- or FOXP3-positive cells is significantly associated with lower mortality in BRCA1- and BRCA2-associated breast cancer and CD8-positive cells are associated with disease-free survival. No heterogeneity according to BRCA gene status was found for the prognostic value of the immune markers.

CONCLUSIONS

The results support a prognostic role of specific T-cell subsets in BRCA-associated breast cancer and the promising potential of targeting the immune system in the treatment of these patients.

Indocyanine green lymphangiography is superior to clinical staging in breast cancer-related lymphedema

Precise staging of breast cancer-related lymphedema (BCRL) is important to guide treatment-decision making. Recent studies have suggested staging of BCRL using indocyanine green lymphangiography (ICG-L) based on the extent of lymphatic injury and dermal backflow patterns. Currently, the benefits of ICG-L compared to conventional clinical staging are unknown. For this study, we included 200 patients with unilateral BCRL. All BCRL patients were staged using ICG-L and clinical exam. The amounts of excess arm volume, fat mass and lean mass were compared between stages using Dual Energy X-Ray Absorptiometry. Multivariate regression models were used to adjust for confounders. For each increase in the patient's ICG-L stage, the excess arm volume, fat mass and lean mass was increased by 8, 12 and 6.5 percentage points respectively (P < 0.001). For each increase in the patient's clinical ISL stage, the volume was increased by 3.5 percentage points (P < 0.05), however no statistically significant difference in the lean and fat mass content of the arm was observed for ascending stages. However, the residual plots showed a high degree of variance for both ICG-L and clinical staging. This study found that ICG-L staging of BCRL was superior to clinical staging in forecasting BCRL excess arm volume, fat mass, and lean mass. However, there was a high degree of variance in excess arm volume, fat mass, and lean mass within each staging system, and neither the ICG-L nor clinical staging forecasted perfectly.

Assessing Techniques for Quantifying the Impact of Bias Due to an Unmeasured Confounder: An Applied Example

Purpose

To compare the magnitude of bias due to unmeasured confounding estimated from various techniques in an applied example.

Patients and Methods

We examined the association between dibutyl phthalate (DBP) and incident estrogen receptor (ER)-positive breast cancer in a Danish nationwide cohort (N=1,122,042). Cox regression analyses were adjusted for age and active drug compounds contributing to DBP exposure. We estimated the hazard ratios (HRs) that would have been observed had one of the DBP sources been unmeasured and calculated the strength of confounding by comparing to the fully adjusted HR. We performed a quantitative bias analysis (QBA) of the “unmeasured” confounder, using external information to specify the bias parameters. Upper bounds on the bias were estimated and E-values were calculated.

Results

The adjusted HR for incident ER-positive breast cancer among women with high-level (≥10,000 cumulative milligrams) versus no DBP exposure was 2.12 (95% confidence interval 1.12 to 4.05). Removing each DBP source in isolation resulted in negligible change in the HR. The bias estimates from the QBA ranged from 1.00 to 1.01. The estimated maximum impact of unmeasured confounding ranged from 1.01 to 1.51. E-values ranged from 3.46 to 3.68.

Conclusion

The impact of bias due to simulated unmeasured confounding was negligible, in part, because the unmeasured variable was not independent of controlled variables. When a suspected confounder cannot be measured in the study data, our exercise suggests that QBA is the most informative method for assessing the impact. E-values may best be reserved for situations where uncontrolled confounding emanates from an unknown confounder.

Cellulitis Is Associated with Severe Breast Cancer-Related Lymphedema: An Observational Study of Tissue Composition

Simple Summary

Cellulitis is a common complication in Breast Cancer-Related Lymphedema (BCRL); however, it is not known whether cellulitis is associated with the severity and biocompositon of BCRL. This study showed that cellulitis was associated with more excess volume, fat, and lean arm mass. Treatments should aim to prevent cellulitis in BCRL to possibly avoid the condition exacerbating.

Abstract

Cellulitis is a common complication in Breast Cancer-Related Lymphedema (BCRL). The excess amount of fat and lean mass in BCRL is a vital factor in patient stratification, prognosis, and treatments. However, it is not known whether cellulitis is associated with the excess fat and lean mass in BCRL. Therefore, this prospective observational study was designed to fundamentally understand the heterogonous biocomposition of BCRL. For this study, we consecutively enrolled 206 patients with unilateral BCRL between January 2019 and February 2020. All patients underwent Dual-Energy X-Ray Absorptiometry scans, bioimpedance spectroscopy, indocyanine green lymphangiography comprehensive history of potential risk factors, and a clinical exam. Multivariate linear and beta regression models were used to determine the strength of association and margins effect. Sixty-nine patients (33%) had at least one previous episode of cellulitis. Notably, a previous episode of cellulitis was associated with 20 percentage points more excess fat and 10 percentage points more excess lean mass compared to patients without cellulitis (p < 0.05). Moreover, each 1 increase in the patients BMI was associated with a 0.03 unit increase in the fat mass proportion of the lymphedema arm. Cellulitis was associated with more excess fat and lean arm mass in BCRL. In addition, patients BMI affect the proportion of fat mass in the arm.

The impact of lymphedema on health-related quality of life up to 10 years after breast cancer treatment

The impact of breast cancer-related lymphedema (BCRL) on long-term quality of life is unknown. The aim of this study was to investigate the impact of BCRL on health-related quality of life (HRQoL) up to 10 years after breast cancer treatment. This regional population-based study enrolled patients treated for breast cancer with axillary lymph node dissection between January 1st 2007 and December 31th 2017. Follow up and assessments of the included patients were conducted between January 2019 and May 2020. The study outcome was HRQoL, evaluated with the Lymphedema Functioning, Disability and Health Questionnaire, the Disabilities of the Arm, Shoulder and Hand Questionnaire and the Short Form (36) Health Survey Questionnaire. Multivariate linear logistic regression models adjusted for confounders provided mean score differences (MDs) with 95% confidence intervals in each HRQoL scale and item. This study enrolled 244 patients with BCRL and 823 patients without BCRL. Patients with BCRL had significantly poorer HRQoL than patients without BCRL in 16 out of 18 HRQoL subscales, for example, in physical function (MDs 27, 95%CI: 24; 30), mental health (MDs 24, 95%CI: 21; 27) and social role functioning (MDs 20, 95%CI: 17; 23). Age, BMI, BCRL severity, hand and dominant arm affection had only minor impact on HRQoL (MDs < 5), suggesting a high degree of inter-individual variation in coping with lymphedema. This study showed that BCRL is associated with long-term impairments in HRQoL, especially affecting the physical and psychosocial domains. Surprisingly, BCRL diagnosis rather than clinical severity drove the largest impairments in HRQoL.

Prospective Validation of Indocyanine Green Lymphangiography Staging of Breast Cancer-Related Lymphedema

Simple Summary

Indocyanine green lymphangiography (ICG-L) allows real-time investigation of lymphatics; however, the applicability in evaluating breast cancer-related lymphedema (BCRL) is sparse and not well established. In this prospective study, we aimed to validate ICG-L assessment of BCRL in a large patient group. We found that evaluation of BCRL with ICG-L was easy and safe to perform in the outpatient clinic and provided unique disease information unobtainable by clinical assessment alone. Future studies that evaluate the efficacy of therapeutic treatments on lymphatic function morphology should incorporate lymphatic imaging as an outcome.

Abstract

Indocyanine green lymphangiography (ICG-L) allows real-time investigation of lymphatics. Plastic surgeons performing lymphatic reconstruction use the ICG-L for patient selection and stratification using the MD Anderson (MDA) and the Arm Dermal Backflow (ADB) grading systems. However, the applicability of ICG-L in evaluating breast cancer-related lymphedema (BCRL) is sparse and not well established. This study comprehensively examines the usability of ICG-L in the assessment of BCRL. We prospectively performed ICG-L in 237 BCRL patients between January 2019 and February 2020. The aim of this study was to assess the interrater and intrarater agreement and interscale consensus of ratings made using the MDA and ADB scales. Three independent raters performed a total of 2607 ICG-L assessments. The ICG-L stage for each grading system was correlated to the lymphedema volume to assess the agreement between the ICG-L stage and clinical severity. The interrater agreement was near perfect for the MDA scale (kappa 0.82–0.90) and the ADB scale (kappa 0.80–0.91). Similarly, we found a near-perfect intrarater agreement for the MDA scale (kappa 0.84–0.94) and the ADB scale (kappa 0.88–0.89). The agreement between the MDA and the ADB scales was substantial (kappa 0.65–0.68); however, the ADB scale systematically overestimated lower ICG-L stages compared to the MDA scale. The volume of lymphedema correlated slightly with MDA stage (Spearmans rho = 0.44, p < 0.001) and ADB stage (r_s = 0.35, p < 0.001). No serious adverse events occurred. The staging of BCRL with ICG-L is reliable, safe, and provides unique disease information unobtainable with clinical measurements alone. The MDA scale seems to provide better disease stratification compared to the ADB scale.

Risk of coronary artery disease after adjuvant radiotherapy in 29,662 early breast cancer patients: A population-based Danish Breast Cancer Group study

PURPOSE

Radiotherapy (RT) for early breast cancer (BC) reduces the risk of recurrence and improves overall survival. However, thoracic RT may cause some incidental RT dose to the heart with subsequent risk of heart disease. During 2000-2010, CT-based RT planning was gradually introduced. The aim of this study was to investigate the risk of cardiac events in left-sided compared with right-sided BC patients treated during a non-CT-based (1999-2007) vs a CT-based period (2008-2016).

MATERIAL AND METHODS

Information on BC and cardiac events among Danish women was obtained from population-based medical registers. Patients diagnosed with BC during 1999-2016, were included. A cardiac event was defined as coronary artery disease or severe valvular heart disease.

RESULTS

Among 29,662 patients, 22,056 received RT. For those irradiated during the non-CT-based period, the 10-year cumulative risk of cardiac event was 1.7% (95% CI 1.4-2.0) at median follow-up of 11.1 years. The incidence rate ratio (IRR) for cardiac event in left-sided vs right-sided patients was 1.44 (1.07-1.94) and a trend towards worse outcome was seen within the first 10 years after RT and approached statistical significance with longer follow-up. Among patients irradiated during the CT-based period, the 10-year cumulative risk of cardiac event was 2.1% (1.8-2.4) at median 6.8 years follow-up. The IRR for cardiac event in left-sided vs right-sided patients was 0.90 (0.69-1.16) and no trend towards worse outcome within the first 10 years was observed.

CONCLUSION

This study confirmed a higher risk of cardiac events in left-sided vs right-sided BC patients irradiated during a non-CT-based period. For patients irradiated during a CT-based period, no increased risk of cardiac events in left-sided vs right-sided patients was observed within the first 10 years after RT, whilst information on cardiac events beyond 10 years after RT was limited.

The power of empirical data; lessons from the clinical registry initiatives in Scandinavian cancer care

BACKGROUND

In Scandinavia, there is a strong tradition for research and quality monitoring based on registry data. In Denmark, Norway and Sweden, 63 clinical registries collect data on disease characteristics, treatment and outcome of various cancer diagnoses and groups based on process-related and outcome-related variables.

AIM

We describe the cancer-related clinical registries, compare organizational structures and quality indicators and provide examples of how these registries have been used to monitor clinical performance, develop prediction models, assess outcome and provide quality benchmarks. Further, we define unmet needs such as inclusion of patient-reported outcome variables, harmonization of variables and barriers for data sharing.

RESULTS AND CONCLUSIONS

The clinical registry framework provides an empirical basis for evidence-based development of high-quality and equitable cancer care. The registries can be used to follow implementation of new treatment principles and monitor patterns of care across geographical areas and patient groups. At the same time, the lessons learnt suggest that further developments and coordination are needed to utilize the full potential of the registry initiative in cancer care.

Incidence of hypothyroidism after treatment for breast cancer-a Danish matched cohort study

Background

Breast cancer survivors (BCS) may have increased risk of hypothyroidism, but risk according to treatment modality is unclear. We estimated the incidence of hypothyroidism in women with breast cancer, and according to cancer treatment.

Methods

Using nationwide registries, we identified all Danish women aged ≥ 35 years diagnosed with non-metastatic breast cancer (1996–2009). We matched up to five cancer-free women (controls) for each BCS. We excluded women with prevalent thyroid disease. Cancer treatment was chemotherapy with or without radiotherapy (RT) targeting the breast/chest wall only, or also the lymph nodes (RTn). We identified hypothyroidism using diagnostic codes, and/or levothyroxine prescriptions. We calculated the cumulative incidence, incidence rates (IR) per 1000 person-years, and used Cox regression to estimate hazard ratios (HR) and associated 95% confidence intervals (CIs) of hypothyroidism, adjusting for comorbidities.

Results

We included 44,574 BCS and 203,306 matched controls with 2,631,488 person-years of follow-up. BCS had a slightly higher incidence of hypothyroidism than controls [5-year cumulative incidence, 1.8% (95%CI = 1.7–1.9) and 1.6% (95%CI = 1.5–1.6), respectively]. The overall IR was 4.45 (95%CI = 4.25–4.67) and 3.81 (95%CI = 3.73–3.90), corresponding to an adjusted HR = 1.17 (95%CI = 1.11–1.24). BCS who received RTn with chemotherapy (HR = 1.74, 95%CI = 1.50–2.02) or without chemotherapy (HR = 1.31, 95%CI = 1.14–1.51) had an elevated risk of hypothyroidism compared with matched controls and compared with BCS who underwent surgery alone [HR = 1.71, 95%CI = 1.45–2.01 and HR = 1.36, 95%CI = 1.17–1.58, respectively].

Conclusions

BCS have an excess risk of hypothyroidism compared with age-matched controls. BCS and those working in cancer survivorship settings ought to be aware that this risk is highest in women treated with radiation therapy to the lymph nodes and chemotherapy.

Induction of PIK3CA alterations during neoadjuvant letrozole may improve outcome in postmenopausal breast cancer patients

PURPOSE

Estrogen receptor positive (ER+) breast cancer constitutes almost 85% of all breast cancer patients and are a genetically highly heterogenic group. Data on the association of somatic alterations to outcome and prognosis are however sparse. In this neoadjuvant endocrine phase II trial including postmenopausal breast cancer patients with ER+, HER2 normal breast cancer, we investigated the rate of pathogenic mutations before and after treatment as well as the association with treatment response and survival.

METHODS

Pretreatment and posttreatment tumour samples from 109 patients treated with neoadjuvant letrozole were collected and analysed with Next Generation Sequencing utilizing a panel of 12 genes (ALK, BRAF, EGFR, ERBB2, ERBB3, ESR1, KIT, KRAS, NRAS, PDGFRA, PIK3CA, and RAF1). Residual disease was assessed by a modified Miller Payne scale and the Residual Cancer Burden index. Survival data were collected prospectively.

RESULTS

Among the 109 patients, 52 had at least one pathogenic mutation in the pretreatment sample and 60 in the posttreatment sample. The most frequently mutated gene was PIK3CA, followed by EGFR and KRAS. Twelve different pathogenic PIK3CA mutations were identified, primarily in exon 20 and exon 9. An altered PIK3CA mutation profile from the pre- to the posttreatment specimen was significantly associated to improved pathological outcome. Overall and Disease-Free Survival benefits in PIK3CA mutated patients was observed.

CONCLUSION

Considerable heterogeneity was identified both among patients and between pre- and posttreatment samples. PIK3CA has the potential to be a predictive biomarker. To further assess the implications of a treatment related altered PIK3CA mutation profile, more data are needed.

Digital Image Analysis of Ki-67 Stained Tissue Microarrays and Recurrence in Tamoxifen-Treated Breast Cancer Patients

Purpose

The proliferation marker Ki-67 has been used as a prognostic marker to separate low- and high-risk breast cancer subtypes and guide treatment decisions for adjuvant chemotherapy. The association of Ki-67 with response to tamoxifen therapy is unclear. High-throughput automated scoring of Ki-67 might enable standardization of quantification and definition of clinical cut-off values. We hypothesized that digital image analysis (DIA) of Ki-67 can be used to evaluate proliferation in breast cancer tumors, and that Ki-67 may be associated with tamoxifen resistance in early-stage breast cancer.

Patients and Methods

Here, we apply DIA technology from Visiopharm using a custom designed algorithm for quantifying the expression of Ki-67, in a case–control study nested in the Danish Breast Cancer Group clinical database, consisting of stages I, II, or III breast cancer patients of 35–69 years of age, diagnosed during 1985–2001, in the Jutland peninsula, Denmark. We assessed DIA-Ki-67 score on tissue microarrays (TMAs) from breast cancer patients in a case–control study including 541 ER-positive and 300 ER-negative recurrent cases and their non-recurrent controls, matched on ER-status, cancer stage, menopausal status, year of diagnosis, and county of residence. We used logistic regression to estimate odds ratios and associated 95% confidence intervals to determine the association of Ki-67 expression with recurrence risk, adjusting for matching factors, chemotherapy, type of surgery, receipt of radiation therapy, age category, and comorbidity.

Results

Ki-67 was not associated with increased risk of recurrence in tamoxifen-treated patients (ORadj =0.72, 95% CI 0.54, 0.96) or ER-negative patients (ORadj =0.85, 95% CI 0.54, 1.34).

Conclusion

Our findings suggest that Ki-67 digital image analysis in TMAs is not associated with increased risk of recurrence among tamoxifen-treated ER-positive breast cancer or ER-negative breast cancer patients. Overall, our findings do not support an increased risk of recurrence associated with Ki-67 expression.

Adherence to treatment guidelines and survival in older women with early-stage breast cancer in Denmark 2008-2012

Objectives: The aims of this study were to compare patients 70 years or older with younger patients, to examine whether Danish patients with early-stage breast cancer aged 70 years or more received treatment according to guidelines, the reasons for deviating from the guidelines, and to analyze whether such deviations affected survival.Methods: From the Danish Breast Cancer Cooperative Group (DBCG) database we identified 23,247 women diagnosed with early-stage breast cancer in Denmark from 2008 to 2012. 17,391 were aged less than 70 years and 5856 were 70+ years. We reviewed medical charts of 441 patients aged 70+ years from Funen (a region of Denmark) to ascertain whether treatment was given according to the guidelines of DBCG and if not, the reason for deviating. Overall survival was analyzed by Cox proportional hazards models.Results: Up to age 80 years most women (94%) had surgery according to guidelines, decreasing to 41% in women aged 85+ years, the main reason for omitting surgery being patients' requests. Patients with breast cancer over the age of 80 years did not have an excess mortality compared with the general population in Funen. Compared with women who had surgery according to guidelines, women who did not have surgery had a significantly higher risk of dying with a hazard ratio (HR) of 8.38 (95% Confidence Intervals (CI) 4.46-15.8) if they were less than 80 years and HR = 2.56 (95% CI 1.63-4.01) if they were 80 years or more (p = .003 for interaction).Conclusions: Adherence to treatment according to guidelines decreases with increasing age, mainly for patients aged 80+ years. Our results suggest that surgery is important for the survival of patients aged less than 80 years.

Long-Term Risk of Heart Failure in Breast Cancer Patients After Adjuvant Chemotherapy With or Without Trastuzumab

OBJECTIVES

This study sought to evaluate the long-term risk of developing heart failure (HF) in patients receiving trastuzumab therapy.

BACKGROUND

Trastuzumab has improved the prognosis in patients with HER2-positive breast cancer, but it can induce left ventricular dysfunction with reduced ejection fraction or HF during treatment. The long-term risk of HF is less well described.

METHODS

In a nationwide Danish retrospective cohort study, 9,901 patients scheduled for adjuvant treatment for early-stage breast cancer were identified in the Danish Breast Cancer Cooperative Group database. Of these, 8,812 patients (25% HER2-positive; 51.7 ± 8.5 years of age) received chemotherapy including anthracycline; and if they were HER2 positive, trastuzumab was added. The primary endpoint was a diagnosis of HF assessed before and after 18 months in a landmark analysis to distinguish short- and long-term risks.

RESULTS

Median follow-up was 5.4 years (interquartile range [IQR]: 4.1 to 6.8 years). In the trastuzumab group, 60 patients had HF by 9 years versus 51 in the group who were treated with chemotherapy alone, corresponding to incidence rates per 1,000 patient years of 5.3 (95% confidence interval [CI]: 4.1 to 6.8) versus 1.4 (95% CI: 1.1 to 1.8), respectively. The cumulative incidence of HF was higher in the trastuzumab group at both the short- and long-term (p < 0.01), yielding adjusted hazard ratios of 8.7 (95% CI: 4.6 to 16.5; p < 0.01) for early HF and 1.9 (95% CI: 1.2 to 3.3; p = 0.01) for late HF associated with trastuzumab treatment.

CONCLUSIONS

Trastuzumab treatment is associated with a 2-fold increased risk of late HF compared with chemotherapy treatment alone.