The path to cancer diagnosis for the elderly.

Older cancer patients are more often than younger diagnosed via an unplanned hospital admission which may negatively influence the prognosis. An increasing number of cancers is expected due to ageing of populations, and these phenomena are likely to result in an increase in older cancer patients with multiple complications, extended hospital stays, and reduced quality of life and survival. In this review, we present recent data about routes to cancer diagnosis for older vs younger patients to emphasize that diagnostic pathways need improvements to avoid an increase in unplanned hospital admissions due to cancer.

Psychiatric disorders and the cancer diagnostic process in general practice: a combined questionnaire and register study exploring the patients' experiences in Denmark.

OBJECTIVE: Patients with psychiatric disorders are at risk of experiencing suboptimal cancer diagnostics and treatment. This study investigates how this patient group perceives the cancer diagnostic process in general practice. DESIGN: Cross-sectional study using questionnaire and register data. SETTING: General practice in Denmark. SUBJECTS: Patients diagnosed with cancer in late 2016 completed a questionnaire about their experiences with their general practitioner (GP) in the cancer diagnostic process (n = 3411). Information on pre-existing psychiatric disorders was obtained from register data on psychiatric hospital contacts and primary care treated psychiatric disorders through psychotropic medications. Logistic regression was used to analyse the association between psychiatric disorders and the patients' experiences. MAIN OUTCOME MEASURES: Patients' experiences, including cancer worry, feeling being taken seriously, and the perceived time between booking an appointment and the first GP consultation.[Box: see text]. RESULTS: A total of 13% of patients had an indication of a psychiatric disorder. This group more often perceived the time interval as too short between the first booking of a consultation and the first GP consultation. Patients with primary care treated psychiatric disorders were more likely to worry about cancer at the first presentation and to share this concern with their GP compared with patients without psychiatric disorders. We observed no statistically significant association between patients with psychiatric disorders and perceiving the waiting time to referral from general practice, being taken seriously, trust in the GP's abilities, and the patients' knowledge of the process following the GP referral. CONCLUSION: The patients' experiences with the cancer diagnostic process in general practice did not vary largely between patients with and without psychiatric disorders. Worrying about cancer may be a particular concern for patients with primary care treated psychiatric disorders.

It is unknown how patients with psychiatric disorders perceive the cancer diagnostic process in general practice.This study found an association between having a psychiatric disorder and more often perceiving the time interval as too short between the first booking of a consultation and the first GP consultation.An association was found between having a primary care treated psychiatric disorder and being worried about cancer and more often sharing these concerns with the GP.Experiences with the cancer diagnostic process in general practice did not differ between patients with a hospital treated psychiatric disorder and patients with no indication of psychiatric disorders.

Healthcare use and clinical investigations before a diagnosis of ovarian cancer: a register-based study in Denmark.

BACKGROUND: Ovarian cancer (OC) is associated with a poor prognosis, which calls for earlier diagnosis. This study aimed to analyse the health care use in primary care and at hospitals among women with OC compared to non-cancerous women to identify a window of opportunity for earlier diagnosis. METHODS: This nationwide register-based observational cohort study included all Danish women aged ≥ 40 years who were diagnosed with a first-time OC or borderline ovarian tumour in 2012-2018 and with no previous cancer diagnosis (n = 4,255). For each case, ten non-cancerous women were identified (n = 42,550). We estimated monthly incidence rate ratios using a negative binomial regression model to assess the use of health care services. We calculated risk ratios of having multiple contacts to general practice before a diagnosis using a binary regression model. RESULTS: Cases had statistically significantly higher contact rates to general practice from five months prior to the diagnosis compared to references. From six to eight months prior to diagnosis, an increased use of transvaginal ultrasound and gynaecologist was seen for cases compared to references. CONCLUSIONS: Increased healthcare use was seen relatively closely to the time of diagnosis for women with OC. This indicates a narrow window of opportunity for a timelier diagnosis. Still, the use of specialised assessment increased at six to eight months before the diagnosis. When women present unspecific symptoms, awareness of potential ovarian malignancies and safety-netting by the general practitioner may be pivotal. TRIAL REGISTRATION: Not relevant.

Healthcare fragmentation, multimorbidity, potentially inappropriate medication, and mortality: a Danish nationwide cohort study.

BACKGROUND: Patients with multimorbidity are frequent users of healthcare, but fragmented care may lead to suboptimal treatment. Yet, this has never been examined across healthcare sectors on a national scale. We aimed to quantify care fragmentation using various measures and to analyze the associations with patient outcomes. METHODS: We conducted a register-based nationwide cohort study with 4.7 million Danish adult citizens. All healthcare contacts to primary care and hospitals during 2018 were recorded. Clinical fragmentation indicators included number of healthcare contacts, involved providers, provider transitions, and hospital trajectories. Formal fragmentation indices assessed care concentration, dispersion, and contact sequence. The patient outcomes were potentially inappropriate medication and all-cause mortality adjusted for demographics, socioeconomic factors, and morbidity level. RESULTS: The number of involved healthcare providers, provider transitions, and hospital trajectories rose with increasing morbidity levels. Patients with 3 versus 6 conditions had a mean of 4.0 versus 6.9 involved providers and 6.6 versus 13.7 provider transitions. The proportion of contacts to the patient's own general practice remained stable across morbidity levels. High levels of care fragmentation were associated with higher rates of potentially inappropriate medication and increased mortality on all fragmentation measures after adjusting for demographic characteristics, socioeconomic factors, and morbidity. The strongest associations with potentially inappropriate medication and mortality were found for ≥ 20 contacts versus none (incidence rate ratio 2.83, 95% CI 2.77-2.90) and ≥ 20 hospital trajectories versus none (hazard ratio 10.8, 95% CI 9.48-12.4), respectively. Having less than 25% of contacts with your usual provider was associated with an incidence rate ratio of potentially inappropriate medication of 1.49 (95% CI 1.40-1.58) and a mortality hazard ratio of 2.59 (95% CI 2.36-2.84) compared with full continuity. For the associations between fragmentation measures and patient outcomes, there were no clear interactions with number of conditions. CONCLUSIONS: Several clinical indicators of care fragmentation were associated with morbidity level. Care fragmentation was associated with higher rates of potentially inappropriate medication and increased mortality even when adjusting for the most important confounders. Frequent contact to the usual provider, fewer transitions, and better coordination were associated with better patient outcomes regardless of morbidity level.

A Validated Register-Based Algorithm to Identify Patients Diagnosed with Recurrence of Surgically Treated Stage I Lung Cancer in Denmark.

Introduction: Recurrence of cancer is not routinely registered in Danish national health registers. This study aimed to develop and validate a register-based algorithm to identify patients diagnosed with recurrent lung cancer and to estimate the accuracy of the identified diagnosis date. Material and Methods: Patients with early-stage lung cancer treated with surgery were included in the study. Recurrence indicators were diagnosis and procedure codes recorded in the Danish National Patient Register and pathology results recorded in the Danish National Pathology Register. Information from CT scans and medical records served as the gold standard to assess the accuracy of the algorithm. Results: The final population consisted of 217 patients; 72 (33%) had recurrence according to the gold standard. The median follow-up time since primary lung cancer diagnosis was 29 months (interquartile interval: 18-46). The algorithm for identifying a recurrence reached a sensitivity of 83.3% (95% CI: 72.7-91.1), a specificity of 93.8% (95% CI: 88.5-97.1), and a positive predictive value of 87.0% (95% CI: 76.7-93.9). The algorithm identified 70% of the recurrences within 60 days of the recurrence date registered by the gold standard method. The positive predictive value of the algorithm decreased to 70% when the algorithm was simulated in a population with a recurrence rate of 15%. Conclusion: The proposed algorithm demonstrated good performance in a population with 33% recurrences over a median of 29 months. It can be used to identify patients diagnosed with recurrent lung cancer, and it may be a valuable tool for future research in this field. However, a lower positive predictive value is seen when applying the algorithm in populations with low recurrence rates.

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.

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.

Characteristics of ovarian cancer patients with first presentation in general practice.

INTRODUCTION: Women with ovarian cancer (OC) have a poor prognosis. An improved prognosis was observed when the pathway to diagnosis begins in general practice. We aimed to investigate patient characteristics among women diagnosed with OC whose diagnostic pathway begins in general practice. METHODS: This was a population-based retrospective cohort study among Danish patients with a first-time OC diagnosis, using questionnaire data and national registers. RESULTS: The GP was involved in the diagnosis in 91.1% of the 313 included women with OC. Women aged 60-74 years had statistically significantly higher odds of having GP involvement than women younger than 60 years (odds ratio (OR) = 2.97 (95% confidence interval (CI): 1.09-8.08)). Women with high comorbidity had statistically significantly lower odds of having GP involvement than women with no comorbidity (OR = 0.25 (95% CI: 0.09-0.66). CONCLUSIONS: This study found higher odds of GP involvement in the diagnosis of OC in women aged 60-74 years and lower odds of GP involvement in women with high comorbidity. The remaining patient characteristics had no significant influence on the first place of presentation for OC patients. Knowledge hereof may potentially inform future initiatives as health campaigns or postgraduate GP training thereby increasing the awareness among women and GPs alike of OC symptoms. However, the study was restricted to a limited number of patients, and future research is warranted to underpin our findings. FUNDING: none. TRIAL REGISTRATION: not relevant.

Patients' health literacy is associated with timely diagnosis of cancer-A cross-sectional study in Denmark.

OBJECTIVE: Timely diagnosis of cancer is important for prognosis. Patients' health literacy (HL) may impact differences of diagnostic delays. Thus, we aim to explore the association between HL and diagnostic intervals in cancer. METHODS: Questionnaire data were obtained from patients with cancer diagnosed in 2016 and their general practitioner (n = 3890). The primary care interval (PCI) and the diagnostic interval (DI) were calculated using dates from national registries and questionnaires. A long PCI and DI were defined as ≥75th percentile. HL was assessed using scales from the Health Literacy Questionnaire: engaging with healthcare providers (scale 6:Engagement, n = 3008), navigating in healthcare (scale 7:Navigation, n = 2827) and understanding health information (scale 9:Knowledge, n = 3002). Low HL was defined as a score ≤3. RESULTS: Low HL was reported by 12.2% (Engagement), 27.0% (Navigation) and 9.3% (Knowledge) of the patients and associated with a long PCI after adjustment of socio-economic factors: Engagement (prevalence rate ratio [PRR] 1.27 [95% CI 1.01-1.60]), Navigation (PRR 1.41 [95% CI 1.10-1.80]) and Knowledge (PRR 1.32 [95% CI 1.03-1.68]). No association was found between HL and DI. CONCLUSION: HL may interfere with the diagnostic processes in general practice. Efforts to manage low HL include GPs' awareness of patients' ability to explain and respond to bodily changes and use of corresponding safety-netting strategies.

Alignment between the patient's cancer worry and the GP's cancer suspicion and the association with the interval between first symptom presentation and referral: a cross-sectional study in Denmark.

BACKGROUND: General practitioners (GPs) have a key role in the diagnosis of cancer. It is crucial to identify factors influencing the decision to refer for suspected cancer. The aim of this study was to investigate the alignment between the patient's cancer worry and the GP's suspicion of cancer in the first clinical encounter and the association with the time interval from the first symptom presentation until the first referral to specialist care, i.e. the primary care interval (PCI). METHOD: The study was performed as a cross-sectional study using survey data on patients diagnosed with incident cancer in 2010 or 2016 and their GPs in Denmark. We defined four alignment groups: 1) patient worry and GP suspicion, 2)  GP suspicion only, 3) patient worry only, and 4) none of the two. A long PCI was defined as an interval longer than the 75th percentile. RESULTS: Among the 3333 included patients, both patient worry and GP suspicion was seen in 39.5%, only GP suspicion was seen in 28.2%, only patient worry was seen in 13.6%, and neither patient worry nor GP suspicion was seen in 18.2%. The highest likelihood of long PCI was observed in group 4 (group 4 vs. group 1: PPR 3.99 (95% CI 3.34-4.75)), mostly pronounced for easy-to-diagnose cancer types. CONCLUSION: Misalignment between the patient's worry and the GP's suspicion was common at the first cancer-related encounter. Importance should be given to the patient interview, due to a potential delayed GP referral among patients diagnosed with "easy-to-diagnose" cancer types presenting with unspecific symptoms.

A Validated Register-Based Algorithm to Identify Patients Diagnosed with Recurrence of Malignant Melanoma in Denmark.

PURPOSE: Information on cancer recurrence is rarely available outside clinical trials. Wide exclusion criteria used in clinical trials tend to limit the generalizability of findings to the entire population of people living beyond a cancer disease. Therefore, population-level evidence is needed. The aim of this study was to develop and validate a register-based algorithm to identify patients diagnosed with recurrence after curative treatment of malignant melanoma. PATIENTS AND METHODS: Indicators of recurrence were diagnosis and procedure codes recorded in the Danish National Patient Register and pathology results recorded in the Danish National Pathology Register. Medical records on recurrence status and recurrence date in the Danish Melanoma Database served as the gold standard to assess the accuracy of the algorithm. RESULTS: The study included 1747 patients diagnosed with malignant melanoma; 95 (5.4%) were diagnosed with recurrence of malignant melanoma according to the gold standard. The algorithm reached a sensitivity of 93.7% (95% confidence interval (CI) 86.8-97.6), a specificity of 99.2% (95% CI: 98.6-99.5), a positive predictive value of 86.4% (95% CI: 78.2-92.4), and negative predictive value of 99.6% (95% CI: 99.2-99.9). Lin's concordance correlation coefficient was 0.992 (95% CI: 0.989-0.996) for the agreement between the recurrence dates generated by the algorithm and by the gold standard. CONCLUSION: The algorithm can be used to identify patients diagnosed with recurrence of malignant melanoma and to establish the timing of recurrence. This can generate population-level evidence on disease-free survival and diagnostic pathways for recurrence of malignant melanoma.

Patient's worry about cancer and the general practitioner's suspicion of cancer or serious illness: A population-based study in Denmark.

OBJECTIVE: A general practitioner's (GP's) suspicion of cancer is important to ensure early diagnosis of cancer. This study aimed to investigate the association between patients' cancer worry and GP's suspicion of cancer or serious illness. METHODS: This population-based study was based on Danish register and questionnaire data from 4,175 incident cancer patients diagnosed in 2010 or 2016 and their GPs. The association between the patient's worry about cancer and their GP's suspicion of cancer or serious illness was estimated by generalised linear models with log link for the Poisson family and presented in prevalence rate ratios (PRR). RESULTS: For 6 in 10 of the cases, the first consultation was categorised by absence of both or either patient worry or GP suspicion. When patients worried about cancer, the GPs were more likely to suspect cancer or serious illness in patients (PRR=1.26, (95%CI: 1.20-1.34)). For all levels of patient worry and most pronounced among very worried patients, GPs less often suspected cancer or serious illness in patients who presented with an ´intermediate´ or ´hard´ to diagnose cancer. CONCLUSION: GPs were more likely to suspect cancer or serious illness in patients who worried about cancer at the first presentation.

Patient's travel distance to specialised cancer diagnostics and the association with the general practitioner's diagnostic strategy and satisfaction with the access to diagnostic procedures: an observational study in Denmark.

BACKGROUND: Research indicate that when general practitioners (GPs) refer their patients for specialist care, the patient often has long distance. This study had a twofold aim: in accordance to the GP's suspicion of cancer, we investigated the association between: 1) cancer patient's travel distance to the first specialised diagnostic facility and the GP's diagnostic strategy and 2) cancer patient's travel distance to the first specialised diagnostic facility and satisfaction with the waiting time and the availability of diagnostic investigations. METHOD: This combined questionnaire- and registry-based study included incident cancer patients diagnosed in the last 6 months of 2016 where the GP had been involved in the diagnostic process of the patients prior to their diagnosis of cancer (n = 3455). The patient's travel distance to the first specialised diagnostic facility was calculated by ArcGIS Network Analyst. The diagnostic strategy, cancer suspicion and the GP's satisfaction with the waiting times and the available investigations were assessed from GP questionnaires. RESULTS: When the GP did not suspect cancer or serious illness, an insignificant tendency was seen that longer travel distance to the first specialised diagnostic facility increased the likelihood of the GP using 'wait-and-see' approach and 'medical treatment' as diagnostic strategies. The GPs of patients with travel distance longer than 49 km to the first specialised diagnostic facility were more likely to report dissatisfaction with the waiting time for requested diagnostic investigations (PR: 1.98, 95% CI: 1.20-3.28). CONCLUSION: A insignificant tendency to use 'wait-and-see' and 'medical treatment' were seen among GPs of patients with long travel distance to the first diagnostic facility when the GP did not suspect cancer or serious illness. Long distance was associated with higher probability of GP dissatisfaction with the waiting time for diagnostic investigations.

Healthcare utilisation in general practice and hospitals in the year preceding a diagnosis of cancer recurrence or second primary cancer: a population-based register study.

BACKGROUND: The organisation of cancer follow-up is under scrutiny in many countries, and general practice is suggested to become more involved. A central focus is timely detection of recurring previous cancer and new second primary cancer. More knowledge on the patient pathway before cancer recurrence and second primary cancer is warranted to ensure the best possible organisation of follow-up. We aimed to describe the healthcare utilisation in the year preceding a diagnosis of cancer recurrence or second primary cancer. METHODS: This nationwide register study comprises patients diagnosed with bladder, breast, colorectal, endometrial, lung, malignant melanoma and ovarian cancer in Denmark in 2008-2016. The frequency of healthcare contacts during the 12 months preceding a cancer recurrence or second primary cancer was estimated and compared to the frequency of cancer survivors in cancer remission. The main analyses were stratified on sex and healthcare setting. Furthermore, two sub-analyses were stratified on 1) sex, healthcare setting and age group and on 2) sex, healthcare setting and comorbidity status. RESULTS: The study population consisted of 7832 patients with recurrence and 2703 patients with second primary cancer. On average, the patients were in contact with general practice one time per month in the 12th month preceding a new cancer diagnosis (recurrence or second primary cancer). Increasing contact rates were seen from 7 months before diagnosis in general practice and from 12 months before diagnosis in hospitals. This pattern was more pronounced in patients with cancer recurrence, younger patients and patients with no comorbidity. For instance, the contact rate ratios for hospital contacts in non-comorbid women with recurrence demonstrated 30% more contacts in the 12th month before recurrence and 127% more contacts in the 2nd month before recurrence. CONCLUSIONS: The results show that cancer survivors are already seen in general practice on a regular basis. The increasing contact rates before a diagnosis of cancer recurrence or second primary cancer indicate that a window of opportunity exists for more timely diagnosis; this is seen in both general practice and in hospitals. Thus, cancer survivors may benefit from improvements in the organisation of cancer follow-up.

Travel distance to cancer-diagnostic facilities and tumour stage.

Specialisation and centralisation in healthcare systems increase patients' travel distance to cancer-diagnostic facilities but the impact of distance on tumour stage remains unclear. This study aimed to study the travel distance to cancer patient's GP and to the hospital of diagnosis and the association with tumour stage for 12 cancer types. A cohort study was conducted including cancer patients in Denmark diagnosed between 2005 and 2016 with rectum, malignant melanoma, breast, testis, oesophageal, colon, cervix, prostate, stomach, pancreatic, lung and ovary cancer (n = 256,663). Distance to each patient's GP and to the hospital of diagnosis were calculated using ArcGIS, Network Analyst. The results showed that for most easy-to-diagnose cancer types (rectum cancer, malignant melanoma, testis cancer) and cervix cancer, increasing travel distance to the hospital of diagnosis increased the odds of advanced disease at diagnosis. Contrary, increasing travel distance to the hospital was associated with decreased odds of being diagnosed with advanced disease stage among hard-to-diagnose cancer types (stomach, pancreatic, lung and ovarian cancer), and prostate cancer. Distance to the GP was overall not associated with tumour stage. The underlying mechanisms for these findings are multifaceted and might reflect differences in presentation, symptomologies and investigations used for diagnosis across cancer types.

Time from incident primary cancer until recurrence or second primary cancer: Risk factors and impact in general practice.

OBJECTIVE: Specialised follow-up care after cancer treatment is changing towards increased involvement of general practice. To ensure timely detection of new cancer events, knowledge is warranted on the timing of cancer recurrence (CR) and second primary cancer (SPC), including risk factors for CR. METHODS: This population-based register study included 67,092 patients diagnosed with malignant melanoma, bladder, lung, ovarian, endometrial, colorectal and breast cancer in Denmark in 2008-2016. The time from primary cancer to CR or SPC and risk factors for prolonged time to CR were analysed and stratified on sex and primary cancer type. RESULTS: Cancer recurrence proportions ranged from 6% to 35%. The risk of CR increased profoundly within the first 3 years and then levelled off, except for breast cancer. A total of 3%-6% of patients had SPC, with monotonously increasing cumulative incidence proportions. Besides primary tumour characteristics, lower educational level, living alone and comorbidity were associated with earlier CR. For example, in female malignant melanoma, HRs and 95% confidence intervals were 0.47 (0.37-0.61) for high educational level, 1.40 (1.16-1.68) for living alone and 2.38 (1.53-3.70) for high comorbidity. CONCLUSION: The results may inform stratified risk assessment in decision of frequency, location and duration of post-cancer follow-up care.

A validated algorithm to identify recurrence of bladder cancer: a register-based study in Denmark.

PURPOSE: Recurrence of cancer is not routinely registered in the national registers in Denmark. The aim of this study was to develop and validate a register-based algorithm to identify patients diagnosed with recurrence of invasive bladder cancer (BC). MATERIALS AND METHODS: We performed a cohort study based on data from Danish national health registers. Diagnosis codes and procedural codes in the Danish National Patient Register and Systematized Nomenclature of Medicine codes in the Danish National Pathology Register were used as indicators of cancer recurrence. Status and date of recurrence as registered in the Danish Bladder Cancer Database (DaBlaCa-data) were used as the gold standard of BC recurrence to ascertain the accuracy of the algorithm. RESULTS: The algorithm reached a sensitivity of 85% (95% CI: 78-91), a specificity of 90% (95% CI: 79-96), and a positive predictive value of 95% (95% CI: 89-98). The algorithm demonstrated superior performance in patients undergoing cystectomy compared to patients undergoing radiotherapy as primary BC treatment. The concordance correlation coefficient for the agreement between the recurrence dates generated by the algorithm and the gold standard was 0.96 (95% CI: 0.95-0.98), and the estimated date was set within 90 days of the gold standard date for 90% of patients. CONCLUSION: The proposed algorithm to identify patients diagnosed with BC recurrence from Danish national registries showed excellent performance in terms of ascertaining occurrence and the timing of BC recurrence.

Non-participation in breast cancer screening among previous cancer patients.

PURPOSE: Breast cancer can be detected at early stages through organised screening. This study explored reasons for non-participation in breast cancer screening among previous cancer patients, who have high risk of developing a new primary cancer. METHOD: We conducted a population-based historical cohort study, including all women invited to the first organised screening round in 2008-2009 in the Central Denmark Region (n = 149,234). All data were based on national registers. RESULTS: Among women with previous cancer (n = 6638), 25.3% did not participate in breast cancer screening compared to 20.9% of women with no registrations of previous cancer, thus previous cancer patients were 21% less likely not to participate in breast cancer screening (PRR 1.21, 95% CI 1.16-1.27). Further analysis showed that this association was due to women receiving current cancer treatment or being in palliative care in the time leading up to screening. Women with previous malignant melanoma or colorectal cancer were more likely to participate in breast cancer screening, whereas women with previous gynaecological or "other" cancer types were less likely to participate. CONCLUSION: Screening for breast cancer may help diagnose breast cancer at an early stage. Women with previous cancer who are not undergoing current treatment or in palliative care have the same propensity to participate as other women invited to breast cancer screening. Women with previous gynaecological cancer were less likely to participate in breast cancer screening than women with other cancer types. These results may only be generalised to similar health care systems.