Introduction Since older patients with breast cancer are underrepresented in clinical trials, an oncogeriatric approach is advocated to guide treatment decisions. However, the effect on outcomes is... Show moreIntroduction Since older patients with breast cancer are underrepresented in clinical trials, an oncogeriatric approach is advocated to guide treatment decisions. However, the effect on outcomes is unclear. The aim of this study was to compare treatments and outcomes between patients treated in an oncogeriatric and a standard care setting. Methods Patients aged >= 70 years with early stage breast cancer were included. Theoncogeriatric cohortcomprised unselected patients from the Moffitt Cancer Center, and thestandard cohortpatients from a Dutch population-based cohort. Cox models were used to characterize the influence of care setting on recurrence risk and overall mortality. Results Overall, 268 patients were included in the oncogeriatric and 1932 patients in the standard cohort. Patients in the oncogeriatric cohort were slightly younger, had more comorbidity, and received more adjuvant endocrine therapy and chemotherapy. Oncogeriatric care was associated with a lower risk of recurrence, which remained significant after adjustment for patient and tumour characteristics [hazard ratio (HR) 0.66, 95% confidence interval (CI) 0.44-0.99]. Oncogeriatric care was also associated with a lower overall mortality, which also remained significant after adjustment for patient and tumour characteristics (HR 0.69, 95% CI 0.55-0.87). Conclusions Patients treated in the oncogeriatric care setting had a lower risk of recurrence, which may be explained by more systemic treatment. Overall mortality was also lower, but other explanations besides care setting could not be ruled out as the cohorts had different patient profiles. Future studies need to clarify the impact of an oncogeriatric approach on outcomes. Show less
Background Many cancer patients use additional herbs or supplements in combination with their anti-cancer therapy. Green tea-active ingredient epigallocatechin-3-gallate (EGCG)-is one of the most... Show moreBackground Many cancer patients use additional herbs or supplements in combination with their anti-cancer therapy. Green tea-active ingredient epigallocatechin-3-gallate (EGCG)-is one of the most commonly used dietary supplements among breast cancer patients. EGCG may alter the metabolism of tamoxifen. Therefore, the aim of this study was to investigate the influence of green tea supplements on the pharmacokinetics of endoxifen; the most relevant active metabolite of tamoxifen. Methods In this single-center, randomized cross-over trial, effects of green tea capsules on endoxifen levels were evaluated. Patients treated with tamoxifen for at least 3 months were eligible for this study. After inclusion, patients were consecutively treated with tamoxifen monotherapy for 28 days and in combination with green tea supplements (1 g twice daily; containing 300 mg EGCG) for 14 days (or vice versa). Blood samples were collected on the last day of monotherapy or combination therapy. Area under the curve (AUC(0-24h)), maximum concentration (C-max) and minimum concentration (C-trough) were obtained from individual plasma concentration-time curves. Results No difference was found in geometric mean endoxifen AUC(0-24h)in the period with green tea versus tamoxifen monotherapy (- 0.4%; 95% CI - 8.6 to 8.5%;p = 0.92). Furthermore, no differences inC(max)(- 2.8%; - 10.6 to 5.6%;p = 0.47) norC(trough)(1.2%; - 7.3 to 10.5%;p = 0.77) were found. Moreover, no severe toxicity was reported during the whole study period. Conclusions This study demonstrated the absence of a pharmacokinetic interaction between green tea supplements and tamoxifen. Therefore, the use of green tea by patients with tamoxifen does not have to be discouraged. Show less
Purpose The diagnosis and treatment of cancer negatively affect patients' physical, functional and psychological wellbeing. Patients' needs for care cannot be addressed unless they are recognized... Show morePurpose The diagnosis and treatment of cancer negatively affect patients' physical, functional and psychological wellbeing. Patients' needs for care cannot be addressed unless they are recognized by healthcare providers (HCPs). The use of quality of life (QoL) assessments with feedback to HCPs might facilitate the identification and discussion of QoL-topics. Methods 113 patients with stage I-IIIB breast cancer treated with chemotherapy were included in this randomized controlled trial. Patients were randomly allocated to receive either usual care, or usual care with an intervention consisting of a QoL-monitor assessing QoL, distress and care needs before every chemotherapy cycle visit. Patients completed questionnaires regarding QoL, illness perceptions, self-efficacy, and satisfaction with communication. From the 2nd visit onwards, patients in the intervention arm and their HCPs received a copy of the QoL overview and results were shown in patients' medical files. Audio-recordings and patients' self-reports were used to investigate effects on communication, patient management and patient-wellbeing. A composite score for communication was calculated by summing the number of QoL-topics discussed during each consultation. Results Use of the QoL-monitor resulted in a higher communication score (0.7 topics increase per visit,p = 0.04), especially regarding the disease-specific and psychosocial issues (p < 0.01). There were no differences in patient management, QoL, illness perceptions or distress. Patients in the experimental arm (n = 60) had higher scores on satisfaction with communication (p < 0.05). Conclusions Use of a QoL-monitor during chemotherapy in patients with early breast cancer might result in a more frequent discussion of QoL-topics, associated with high levels of patients' satisfaction. Show less
Purpose Breast-contour preservation (BCP) is possible for most women treated for early-stage breast cancer. BCP can be defined as primary breast-conserving treatment (BCT), neoadjuvant chemotherapy... Show morePurpose Breast-contour preservation (BCP) is possible for most women treated for early-stage breast cancer. BCP can be defined as primary breast-conserving treatment (BCT), neoadjuvant chemotherapy (NAC) followed by BCT and immediate postmastectomy breast reconstruction (IBR). This study provides insight in current BCP strategies in Denmark and the Netherlands and aims to identify opportunities for improvement within both countries. Methods A total of 92,881 patients with early-stage breast cancer who were operated in Denmark and the Netherlands between 2012 and 2017 were selected from the Danish Breast Cancer Group and the Dutch National Breast Cancer Audit databases. BCP procedures and predictive factors were analyzed within and between both countries. Results BCP was achieved in 76.7% (n = 16,355) of the Danish and in 74.5% (n = 53,328) of the Dutch patients. While BCP rate did not change significantly over time in Denmark (p = 0.250), a significant increase in BCP rate from 69.5% in 2012 to 78.5% in 2017 (p < 0.001) was observed in the Netherlands. In both countries, variation in BCP rates between hospitals decreased over time. NAC followed by BCT and postmastectomy IBR was substantially more often used in the Netherlands compared to Denmark, specifically in patients younger than 50 years. Conclusions In more than 75% of all Danish and Dutch patients, surgically treated for early-stage breast cancer, the breast-contour was preserved. The different use of BCP strategies within Denmark and the Netherlands and the differences observed between hospitals in both countries emphasize the need for more (inter)national consensus on treatment modalities. Show less
In summary, this thesis focused on the understanding the underlying mechanisms driving TNBC metastatic progression. We established DUB activity profiling methods and identified UCHL1 as a candidate... Show moreIn summary, this thesis focused on the understanding the underlying mechanisms driving TNBC metastatic progression. We established DUB activity profiling methods and identified UCHL1 as a candidate oncoprotein that promotes TGFβ-induced breast cancer metastasis. Importantly, we found UCHL1 activity inhibitor as a potential drug for TNBC therapy and developed UCHL1 activity-based probe. For vemurafenib-resistance melanoma, we provided insights that targeting TGFβ signaling may help to overcome drug resistant phenotype. Show less
Ductal carcinoma in situ (DCIS) is considered to be a non-obligate precursor of invasive breast cancer (IBC). Optimal clinical management of DCIS remains controversial, as we are unable to... Show moreDuctal carcinoma in situ (DCIS) is considered to be a non-obligate precursor of invasive breast cancer (IBC). Optimal clinical management of DCIS remains controversial, as we are unable to identify those DCIS lesions with invasive potential. As a result, current treatment guidelines for DCIS dictate that all women diagnosed with DCIS should undergo treatment to prevent the development of IBC. This makes that many women, who have a low-risk to develop subsequent IBC, are being harmed by this intensive treatment without any benefit. Furthermore, definite proof of DCIS progression to IBC is still lacking.The objectives of this thesis were to identify prognostic markers predictive of the development of subsequent ipsilateral IBC after DCIS and to explore the clonal relatedness of patient-matched DCIS and subsequent ipsilateral IBC. To achieve this, histopathological analysis and molecular profiling were performed using a patient group which was part of a nation-wide population-based cohort including all women diagnosed with and treated for DCIS with breast conserving surgery alone in the Netherlands between 1989 and 2005. The results presented in this thesis will help to stratify a woman’s individual risk of subsequent invasive breast cancer development and will help to avoid overtreatment. Show less
Hellemond, I.E.G. van; Smorenburg, C.H.; Peer, P.G.M.; Swinkels, A.C.P.; Seynaeve, C.M.; Sangen, M.J.C. van der; ... ; Dutch Breast Canc Res Grp BOOG 2020
Purpose The phase III DATA study compared 6 and 3 years of adjuvant anastrozole following 2-3 years of tamoxifen in postmenopausal breast cancer patients. This pre-planned side-study assessed the... Show morePurpose The phase III DATA study compared 6 and 3 years of adjuvant anastrozole following 2-3 years of tamoxifen in postmenopausal breast cancer patients. This pre-planned side-study assessed the relationship between a reduced bone mineral density (BMD) and distant recurrence-free survival (DRFS), and evaluated the effect of bisphosphonates on DRFS. Methods We selected all patients with a BMD measurement within 3 years after randomisation (landmark) without any DRFS events. Kaplan-Meier methods and Cox proportional hazards models were used for analyses. Results Of 1860 eligible patients, 1142 had a DEXA scan before the landmark. The BMD was normal in 436 (38.2%) and showed osteopenia in 565 (49.5%) and osteoporosis in 141 (12.3%) patients. After a median follow-up of 5.0 years from the landmark, neither osteopenia nor osteoporosis (compared with normal BMD) were associated with DRFS in both the 6-year [osteopenia HR 0.82 (95% CI 0.45-1.49), osteoporosis HR 1.10 (95% CI 0.26-4.67)] and the 3-year arm [osteopenia HR 0.75 (95% CI 0.40-1.42), osteoporosis HR 1.86 (95% CI 0.43-8.01)]. Moreover, bisphosphonate use did not impact DRFS. Conclusion No association was observed between a reduced BMD and DRFS. Neither did we observe an impact of bisphosphonates on DRFS. Show less
Purpose To describe practice patterns and patient outcomes with respect to the use of postoperative systemic therapy (ST) after resection of a solitary breast cancer brain metastasis (BCBM).... Show morePurpose To describe practice patterns and patient outcomes with respect to the use of postoperative systemic therapy (ST) after resection of a solitary breast cancer brain metastasis (BCBM). Methods A multi-institutional retrospective review of consecutive patients undergoing resection of a single BCBM without extracranial metastases was performed to describe subtype-specific postoperative outcomes and assess the impact of types of ST on site of recurrence, progression-free survival (PFS), and overall survival (OS). Results Forty-four patients were identified. Stratified estimated survival was 15, 24, and 23 months for patients with triple negative, estrogen receptor positive (ER+), and HER2+ BCBMs, respectively. Patients receiving postoperative ST had a longer median PFS (8 versus 4 months, adjusted p-value 0.01) and OS (32 versus 15 months, adjusted p-value 0.21). Nine patients (20%) had extracranial progression, 23 (52%) had intracranial progression, three (8%) had both, and nine (20%) did not experience progression at last follow-up. Multivariate analysis showed that postoperative hormonal therapy was associated with longer OS (HR 0.26; 95% CI 0.08-0.89; p = 0.03) but not PFS (HR 0.35, 95% CI 0.08-1.47, p = 0.15) in ER+ patients. Postoperative HER2-targeted therapy was not associated with longer OS or PFS in HER2+ patients. Conclusions Disease progression occurred intracranially more often than extracranially following resection of a solitary BCBM. In ER+ patients, postoperative hormonal therapy was associated with longer OS. Postoperative HER2-targeted therapy did not show survival benefit in HER2+ patients. These results should be validated in larger cohorts. Show less
Background The effect of risk-reducing salpingo-oophorectomy (RRSO) on breast cancer risk for BRCA1 and BRCA2 mutation carriers is uncertain. Retrospective analyses have suggested a protective... Show moreBackground The effect of risk-reducing salpingo-oophorectomy (RRSO) on breast cancer risk for BRCA1 and BRCA2 mutation carriers is uncertain. Retrospective analyses have suggested a protective effect but may be substantially biased. Prospective studies have had limited power, particularly for BRCA2 mutation carriers. Further, previous studies have not considered the effect of RRSO in the context of natural menopause. Methods A multi-centre prospective cohort of 2272 BRCA1 and 1605 BRCA2 mutation carriers was followed for a mean of 5.4 and 4.9 years, respectively; 426 women developed incident breast cancer. RRSO was modelled as a time-dependent covariate in Cox regression, and its effect assessed in premenopausal and postmenopausal women. Results There was no association between RRSO and breast cancer for BRCA1 (HR = 1.23; 95% CI 0.94-1.61) or BRCA2 (HR = 0.88; 95% CI 0.62-1.24) mutation carriers. For BRCA2 mutation carriers, HRs were 0.68 (95% CI 0.40-1.15) and 1.07 (95% CI 0.69-1.64) for RRSO carried out before or after age 45 years, respectively. The HR for BRCA2 mutation carriers decreased with increasing time since RRSO (HR = 0.51; 95% CI 0.26-0.99 for 5 years or longer after RRSO). Estimates for premenopausal women were similar. Conclusion We found no evidence that RRSO reduces breast cancer risk for BRCA1 mutation carriers. A potentially beneficial effect for BRCA2 mutation carriers was observed, particularly after 5 years following RRSO. These results may inform counselling and management of carriers with respect to RRSO. Show less
Purpose The tumour microenvironment in older patients is subject to changes. The tumour-stroma ratio (TSR) was evaluated in order to estimate the amount of intra-tumoural stroma and to evaluate the... Show morePurpose The tumour microenvironment in older patients is subject to changes. The tumour-stroma ratio (TSR) was evaluated in order to estimate the amount of intra-tumoural stroma and to evaluate the prognostic value of the TSR in older patients with breast cancer (>= 70 years). Methods Two retrospective cohorts, the FOCUS study (N = 619) and the Nottingham Breast Cancer series (N = 1793), were used for assessment of the TSR on haematoxylin and eosin stained tissue slides. Results The intra-tumoural stroma increases with age in the FOCUS study and the Nottingham Breast Cancer series (B 0.031, 95% CI 0.006-0.057, p = 0.016 and B 0.034, 95% CI 0.015-0.054, p < 0.001, respectively). Fifty-one per cent of the patients from the Nottingham Breast Cancer series < 40 years had a stroma-high tumour compared to 73% of the patients of >= 90 years from the FOCUS study. The TSR did not validate as an independent prognostic parameter in patients >= 70 years. Conclusions The intra-tumoural stroma increases with age. This might be the result of an activated tumour microenvironment. The TSR did not validate as an independent prognostic parameter in patients >= 70 years in contrast to young women with breast cancer as published previously. Show less
Liu, S.; González, Prieto R.; Zhang, M.; Geurink, P.P.; Kooij, R.; Iyengar, P.V.; ... ; Dijke, P. ten 2019
Therapies directed to specific molecular targets are still unmet for triple-negative breast cancer (TNBC) patients. Deubiquitinases (DUBs) are emerging drug targets. The identification of a highly... Show moreTherapies directed to specific molecular targets are still unmet for triple-negative breast cancer (TNBC) patients. Deubiquitinases (DUBs) are emerging drug targets. The identification of a highly active DUBs in TNBC may lead to novel therapies.\n biochemical methods. A specific inhibitor was synthesised and its biochemical and biological functions were assessed in a range of assays. Finally, we used patient sera samples to investigate clinical correlations.\nTwo DUB activity profiling approaches identified UCHL1 as being highly active in TNBC cell lines and aggressive tumors. Functionally, UCHL1 promoted metastasis in zebrafish and murine breast cancer xenograft models. Mechanistically, UCHL1 facilitates TGFβ signaling-induced metastasis by protecting TGFβ type I receptor and SMAD2 from ubiquitination. We found that these responses are potently suppressed by the specific UCHL1 inhibitor, 6RK73. Furthermore, UCHL1 levels were significantly increased in TNBC patient sera, and highly enriched in sera exosomes as well as TNBC cell conditioned media. UCHL1 enriched exosomes stimulated breast cancer migration and extravasation, suggesting that UCHL1 may act in a paracrine manner to promote tumor progression.\nOur DUB activity profiling identified UCHL1 as a candidate oncoprotein that promotes TGFβ-induced breast cancer metastasis and may provide a potential target for TNBC treatment. Show less
In this thesis, we aimed to better understand the underlying mechanisms involved in TNBC progression and metastasis formation and discover new targets to reduce breast cancer related deaths. We... Show moreIn this thesis, we aimed to better understand the underlying mechanisms involved in TNBC progression and metastasis formation and discover new targets to reduce breast cancer related deaths. We performed an imaging-based RNAi phenotypic cell migration screen in two highly motile TNBC cancer cell lines to provide a repository of signaling determinants that functionally drive TNBC cell motility. Interestingly, two modulators essential for cancer cell migration were known to be involved in RNA splicing, making us decide to focus on the role of RNA splicing in breast cancer progression. We next summarized the current knowledge about splicing factors in breast cancer development and progression and identified co-regulated splicing factors that were associated with aggressive breast cancer phenotypes and metastasis formation that was not only restricted to breast cancer, increasing the global understanding of the role of the spliceosome in cancer development and progression. Moreover, the role of splicing factors in two major processes in cancer progression, cell migration and proliferation, was examined. Finally, using RNA sequencing, we systematically compared the transcriptomes of 14 breast cancer cell lines cultured both in 2D and 3D conditions to unravel the reprogramming that is associated with the invasive phenotype of basal B TNBC. Show less
Purpose In the Netherlands, radiotherapy after breast-conserving surgery (BCS) is omitted in up to 30% of patients aged >= 75 years. Although omission of radiotherapy is considered an option for... Show morePurpose In the Netherlands, radiotherapy after breast-conserving surgery (BCS) is omitted in up to 30% of patients aged >= 75 years. Although omission of radiotherapy is considered an option for older women treated with endocrine treatment, the majority of these patients do not receive systemic treatment following Dutch treatment guidelines. Therefore, the aim of this study was to evaluate the effect of omission of radiotherapy on locoregional recurrence risk in this patient population.Methods Patients aged >= 75 years undergone BCS for T1-2N0 breast cancer diagnosed between 2003 and 2009 were selected from the Netherlands Cancer Registry. To minimize confounding by indication, hospital variation was used to assess the impact of radiotherapy-use on locoregional recurrence risk using cox proportional hazards regression. Hazards ratios with 95% confidence interval (CI) were estimated.Results Overall, 2390 patients were included. Of the patients with hormone receptor-positive breast cancer, 39.3% received endocrine treatment. Five-year incidences of locoregional recurrence were 1.9%, 2.8%, and 3.0% in patients treated at hospitals with higher (average radiotherapy-use 96.0%), moderate (88.0%), and lower radiotherapy-use (72.2%) respectively, and nine-year incidences were 2.2%, 3.1%, and 3.2% respectively. Adjusted hazard ratios were 1.46 (95% CI 0.77-2.78) and 1.50 (95% CI 0.79-2.85) for patients treated at hospitals with moderate and lower radiotherapy-use, compared to patient treated at hospitals with higher radiotherapy-use.Conclusions Despite endocrine treatment in only 39.3%, locoregional recurrence risk was low, even in patients treated at hospitals with lower radiotherapy-use. This provides reasonable grounds to consider omission of radiotherapy in patients aged >= 75 years with T1-2N0 breast cancer. Show less
Glas, N. de; Bastiaannet, E.; Boer, A. de; Siesling, S.; Liefers, G.J.; Portielje, J. 2019
PurposeThe number of older patients with breast cancer is rapidly increasing. A previous study showed that between 1990 and 2005, the survival of older patients with breast cancer did not improve... Show morePurposeThe number of older patients with breast cancer is rapidly increasing. A previous study showed that between 1990 and 2005, the survival of older patients with breast cancer did not improve in contrast to younger patients. In recent years, scientific evidence in the older age group has increased and specific guidelines for older women with breast cancer have been developed. The aim of this study was to assess changes in survival outcomes of older patients with breast cancer.Patients and methodsAll patients with breast cancer between 2000 and 2017 were included from the Netherlands cancer registry. We assessed changes in treatments using logistic regression. We calculated changes in relative survival as proxy for breast cancer mortality, stratified by age and stage.ResultsWe included 239,992 patients. Relative survival improved for patients<65 for all stages. In patients aged 65-75 years, relative survival did not improve in stage I-II but did improve in stage III breast cancer (RER 0.98, 95% CI 0.96-1.00, p=0.046). Concurrently, prescription of systemic treatments increased. In patients>75, relative survival did not improve in patients with stage I/II or stage III disease, nor did treatment strategies change.ConclusionsThis study shows that relative survival of patients aged 65-75 years with advanced breast cancer has improved, and concurrently, prescription of systemic treatment increased. To improve survival of patients >75 as well, future studies should focus on individualizing treatments based on concomitant comorbidity, geriatric parameters and the risk of competing mortality and toxicity of treatments. Show less
My PhD studies focused on understanding the role of macrophages, a type of immune cells which are abundantly present in several tumor types, in breast cancer progression and therapy response.In the... Show moreMy PhD studies focused on understanding the role of macrophages, a type of immune cells which are abundantly present in several tumor types, in breast cancer progression and therapy response.In the first part of my thesis, I describe how macrophages can acquire different functional characteristics in different types of breast cancer. Next, I focused on understanding the interplay between macrophages and cancer therapies. In particular, I revealed that macrophages counteract the efficacy of conventional chemotherapy drugs. I showed that eliminating macrophages with an antibody that targets CSF-1 receptor (CSF-1R) enhances the anti-cancer efficacy of platinum-based chemotherapeutic agents in breast cancer. I mechanistically discovered that CSF-1R inhibition stimulates intratumoral type I interferon signaling which is essential for the therapeutic synergy between cisplatin and CSF-1R blockade. I also uncovered that further elimination of immunosuppressive neutrophils, another type of immune cells, was required to engage an efficacious anti-tumor immunity. Show less
Koedoot, E.; Wolters, L.; Water, B. van de; Dévédec, S.E.L. 2019
By regulating transcript isoform expression levels, alternative splicing provides an additional layer of protein control. Recent studies show evidence that cancer cells use different splicing... Show moreBy regulating transcript isoform expression levels, alternative splicing provides an additional layer of protein control. Recent studies show evidence that cancer cells use different splicing events to fulfill their requirements in order to develop, progress and metastasize. However, there has been less attention for the role of the complex catalyzing the complicated multistep splicing reaction: the spliceosome. The spliceosome consists of multiple sub-complexes in total comprising 244 proteins or splice factors and 5 associated RNA molecules. Here we discuss the role of splice factors in the oncogenic processes tumors cells need to fulfill their oncogenic properties (the so-called the hallmarks of cancer). Despite the fact that splice factors have been investigated only recently, they seem to play a prominent role in already five hallmarks of cancer: angiogenesis, resisting cell death, sustaining proliferation, deregulating cellular energetics and invasion and metastasis formation by affecting major signaling pathways such as epithelial-to-mesenchymal transition, the Warburg effect, DNA damage response and hormone receptor dependent proliferation. Moreover, we could relate expression of representative genes of four other hallmarks (enabling replicative mortality, genomic instability, avoiding immune destruction and evading growth suppression) to splice factor levels in human breast cancer tumors, suggesting that also these hallmarks could be regulated by splice factors. Since many splice factors are involved in multiple hallmarks of cancer, inhibiting splice factors might provide a new layer of oncogenic control and a powerful method to combat breast cancer progression. Show less
Acker, T. van; Buckle, T.; Malderen, S.J.M. van; Willigen, D.M. van; Unen, V. van; Leeuwen, F.W.B. van; Vanhaecke, F. 2019
Background Studies have demonstrated worse breast cancer-specific mortality with older age, despite an increasing risk of dying from other causes due to comorbidity (competing mortality). However,... Show moreBackground Studies have demonstrated worse breast cancer-specific mortality with older age, despite an increasing risk of dying from other causes due to comorbidity (competing mortality). However, findings on the association between older age and recurrence risk are inconsistent. The aim of this study was to assess incidences of locoregional and distant recurrence by age, taking competing mortality into account. Materials and Methods Patients surgically treated for nonmetastasized breast cancer between 2003 and 2009 were selected from The Netherlands Cancer Registry. Cumulative incidences of recurrence were calculated considering death without distant recurrence as competing event. Fine and Gray analyses were performed to characterize the impact of age (70-74 [reference group], 75-79, and >= 80 years) on recurrence risk. Results A total of 18,419 patients were included. Nine-year cumulative incidences of locoregional recurrence were 2.5%, 3.1%, and 2.9% in patients aged 70-74, 75-79, and >= 80 years, and 9-year cumulative incidences of distant recurrence were 10.9%, 15.9%, and 12.7%, respectively. After adjustment for tumor and treatment characteristics, age was not associated with locoregional recurrence risk. For distant recurrence, patients aged 75-79 years remained at higher risk after adjustment for tumor and treatment characteristics (75-79 years subdistribution hazard ratio [sHR], 1.25; 95% confidence interval [CI], 1.11-1.41; >= 80 years sHR, 1.03; 95% CI, 0.91-1.17). Conclusion Patients aged 75-79 years had a higher risk of distant recurrence than patients aged 70-74 years, despite the higher competing mortality. Individualizing treatment by using prediction tools that include competing mortality could improve outcome for older patients with breast cancer. Implications for Practice In this population-based study of 18,419 surgically treated patients aged 70 years or older, patients aged 75-79 years were at higher risk of distant recurrence than were patients aged 70-74 years. This finding suggests that patients in this age category are undertreated. In contrast, it was also demonstrated that the risk of dying without a recurrence strongly increases with age, and patients with a high competing mortality risk are easily overtreated. To identify older patients who may benefit from more treatment, clinicians should therefore take competing mortality risk into account. Prediction tools could facilitate this and thereby improve treatment strategy. Show less
