Infections in patients with mantle cell lymphoma.

Advancements in treatments have significantly improved the prognosis for mantle cell lymphoma (MCL), and there is a growing population of survivors with an increased susceptibility to infections. We assessed the incidence of infections by clinical characteristics and treatment both before and after MCL diagnosis in Sweden. Patients with a diagnosis of MCL ≥ 18 years between 2007 and 2019 were included, along with up to 10 matched comparators. Infectious disease diagnosis and anti-infective drug dispensation were identified by the National Patient and the Prescribed Drug Registers, respectively. Patients and comparators were followed from the diagnosis/matching date until death, emigration, or June 30, 2020. Overall, 1559 patients and 15,571 comparators were followed for a median duration of 2.9 and 5 years, respectively. The infection rate among patients was twofold higher, RRadj = 2.14 (2.01-2.27), contrasted to the comparator group. There was a notable rise in infection rates already 4 years before MCL diagnosis, which reached a fourfold increase in the first year after diagnosis and persisted significantly increased for an additional 8 years. Among patients, 69% (n = 1080) experienced at least one infection during the first year of follow-up. Influenza, pneumonia, other bacterial infections, urinary tract infections, and acute upper respiratory infections were the most frequent. Notably, MCL remained to be the primary leading cause of death among patients (57%, n = 467/817). Infections as the main cause of death were rare (2.6%, n = 21). Our study highlights the importance of thoroughly assessing infectious morbidity when appraising new treatments. Further investigations are warranted to explore strategies for reducing infectious disease burden.

Trends in lung cancer survival in the Nordic countries 1990-2016: The NORDCAN survival studies.

OBJECTIVES: The aim of this study was to evaluate if the previously reported improvements in lung cancer survival were consistent across age at diagnosis and by lung cancer subtypes. MATERIALS AND METHODS: Data on lung cancers diagnosed between 1990 and 2016 in Denmark, Finland, Iceland, Norway and Sweden were obtained from the NORDCAN database. Flexible parametric models were used to estimate age-standardized and age-specific relative survival by sex, as well as reference-adjusted crude probabilities of death and life-years lost. Age-standardised survival was also estimated by the three major subtypes; adenocarcincoma, squamous cell and small-cell carcinoma. RESULTS: Both 1- and 5-year relative survival improved continuously in all countries. The pattern of improvement was similar across age groups and by subtype. The largest improvements in survival were seen in Denmark, while improvements were comparatively smaller in Finland. In the most recent period, age-standardised estimates of 5-year relative survival ranged from 13% to 26% and the 5-year crude probability of death due to lung cancer ranged from 73% to 85%. Across all Nordic countries, survival decreased with age, and was lower in men and for small-cell carcinoma. CONCLUSION: Lung cancer survival has improved substantially since 1990, in both women and men and across age. The improvements were seen in all major subtypes. However, lung cancer survival remains poor, with three out of four patients dying from their lung cancer within five years of diagnosis.

Have the recent advancements in cancer therapy and survival benefitted patients of all age groups across the Nordic countries? NORDCAN survival analyses 2002-2021.

BACKGROUND: Since the early 2000s, overall and site-specific cancer survival have improved substantially in the Nordic countries. We evaluated whether the improvements have been similar across countries, major cancer types, and age groups. MATERIAL AND METHODS: Using population-based data from the five Nordic cancer registries recorded in the NORDCAN database, we included a cohort of 1,525,854 men and 1,378,470 women diagnosed with cancer (except non-melanoma skin cancer) during 2002-2021, and followed for death until 2021. We estimated 5-year relative survival (RS) in 5-year calendar periods, and percentage points (pp) differences in 5-year RS from 2002-2006 until 2017-2021. Separate analyses were performed for eight cancer sites (i.e. colorectum, pancreas, lung, breast, cervix uteri, kidney, prostate, and melanoma of skin). RESULTS: Five-year RS improved across nearly all cancer sites in all countries (except Iceland), with absolute differences across age groups ranging from 1 to 21 pp (all cancer sites), 2 to 20 pp (colorectum), -1 to 36 pp (pancreas), 2 to 28 pp (lung), 0 to 9 pp (breast), -11 to 26 pp (cervix uteri), 2 to 44 pp (kidney), -2 to 23 pp (prostate) and -3 to 30 pp (skin melanoma). The oldest patients (80-89 years) exhibited lower survival across all countries and sites, although with varying improvements over time. INTERPRETATION: Nordic cancer patients have generally experienced substantial improvements in cancer survival during the last two decades, including major cancer sites and age groups. Although survival has improved over time, older patients remain at a lower cancer survival compared to younger patients.

Non-preventable cases of breast, prostate, lung, and colorectal cancer in 2050 in an elimination scenario of modifiable risk factors.

Most Western countries have increasing number of new cancer cases per year. Cancer incidence is primarily influenced by basically avoidable risk factors and an aging population. Through hypothetical elimination scenarios of multiple major risk factors for cancer, we estimated the number of new cancer cases that are non-preventable in 2050. We compare numbers of new postmenopausal breast, prostate, lung, and colorectal cancer cases in 2021 to projected numbers of new cases in 2050 under prevention scenarios regarding smoking, overweight and obesity, and alcohol consumption: no intervention, 50%, and 100% instant reduction. Cancer incidence data were derived from NORDCAN, and risk factor prevalence data from the Danish National Health Survey. Cancer projections were calculated with the Prevent program. Hypothetical 100% instant elimination of major risk factors for cancer in Denmark in 2022 will result in unchanged numbers of new breast and colorectal cancers in 2050. The number of new prostate cancers will increase by 25% compared to 2021. Unchanged risk factor levels will result in noticeable increase in cancer burden. Increase in life expectancy and age will entail an increase in cancer incidence, despite maximum effect of preventive actions in the population. Our results are important when planning future health care.

Childbirth rates in women with myeloproliferative neoplasms.

Myeloproliferative neoplasms (MPN) are associated with inferior pregnancy outcome, however, little is known about fertility and childbearing potential in women with MPN. In this study we aimed to describe reproductive patterns, as well as to quantify risk of miscarriage and stillbirth. Women aged 15-44 years with an MPN diagnosis 1973-2018, were identified in Swedish health care registers, and age-matched 1:4 to population controls. We identified 1141 women with MPN and 4564 controls. Women with MPN had a lower rate of childbirth (hazard ratio [HR] with 95% confidence interval was 0.78 (0.68-0.90)). Subgroup analysis showed that the rate was not significantly reduced in essential thrombocythemia, HR 1.02 (0.86-1.22) while the HR was 0.50 (0.33-0.76) in PV and 0.45 (0.28-0.74) in PMF. The risk of miscarriage was not significantly increased before MPN diagnosis, the HR during follow-up after diagnosis was 1.25 (0.89-1.76). Women with MPN were more likely to have had a previous stillbirth. Women with MPN had fewer children at diagnosis, and fewer children in total. In conclusion, the childbirth rate was lower among women with MPN than controls, but not among women with essential thrombocythemia.

Survival trends for patients diagnosed with cutaneous malignant melanoma in the Nordic countries 1990-2016: The NORDCAN survival studies.

BACKGROUND: The survival in patients diagnosed with cutaneous malignant melanoma (CMM) has improved in the Nordic countries in the last decades. It is of interest to know if these improvements are observed in all ages and for both women and men. METHODS: Patients diagnosed with CMM in the Nordic countries in 1990-2016 were identified in the NORDCAN database. Flexible parametric relative survival models were fitted, except for Iceland where a non-parametric Pohar-Perme approach was used. A range of survival metrics were estimated by sex, both age-standardised and age-specific. RESULTS: The 5-year relative survival improved in all countries, in both women and men and across age. While the improvement was more pronounced in men, women still had a higher survival at the end of the study period. The survival was generally high, with age-standardised estimates of 5-year relative survival towards the end of the study period ranging from 85% in Icelandic men to 95% in Danish women. The age-standardised and reference-adjusted 5-year crude probability of death due to CMM ranged from 5% in Danish and Swedish women to 13% in Icelandic men. CONCLUSION: Although survival following CMM was relatively high in the Nordic countries in 1990, continued improvements in survival were observed throughout the study period in both women and men and across age.

Loss in life expectancy in patients with stage II-III cutaneous melanoma in Sweden: A population-based cohort study.

BACKGROUND: Survival in cutaneous melanoma (CM) is heterogeneous. Loss in life expectancy (LLE) measures impact of CM on remaining lifespan compared to general population. OBJECTIVES: Investigating LLE in operated stage II-III CM patients. METHODS: Data from 8061 patients (aged 40-80 years) with stage II-III CM in Sweden, diagnosed between 2005 and 2018, were analyzed (Swedish Melanoma Registry). A flexible parametric survival model estimated life expectancy and LLE. RESULTS: Based on 2018 diagnoses, stage II and III CM patients lost 2209 and 1902 life years, respectively. LLE was higher in stage III: 5.2 versus 10.9 years (stage II vs III 60-year-old females). Younger patients had higher LLE: 10.7 versus 3.9 years (stage II CM in 40 vs 70-year-old males). In stage II, females had lower LLE than males; 50-year-old females and males stage II CM had LLE equal to 7.3 and 8.3 years, respectively. LLE increased with higher substages, stage IIB resembling IIIB and IIC resembling IIIC-D. LIMITATIONS: Extrapolation was used to estimate LLE. Varying stage group sizes require caution. CONCLUSIONS: Our results are both clinically relevant and easy-to-interpret measures of the impact of CM on survival, but the results also summarize the prognosis over the lifetime of a CM patient.

Despite multi-disciplinary team discussions the socioeconomic disparities persist in the oncological treatment of non-metastasized colorectal cancer.

BACKGROUND: The introduction of national guidelines should eliminate previously observed associations between socioeconomic status (SES) and colorectal cancer treatment. The aim of the study was to investigate whether inequalities remain. METHODS: CRCBaSe, a register-linkage originating from the Swedish Colorectal Cancer Registry, was used to identify information on patient and tumour characteristics, for 83,460 patients with stage I-III disease diagnosed 2008-2021. SES was measured as disposable income (quartiles) and the highest level of education. Outcomes of interest were emergency surgery, multidisciplinary team (MDT) conference discussion, and oncological treatment. Differences in treatment between SES groups were explored using multivariable logistic regression adjusted for year of diagnosis, age at diagnosis, sex, civil status, comorbidities, tumour location and stage. RESULTS: Patients in the highest income quartile had a lower risk of emergency surgery (OR 0.73 95%CI 0.68-0.80), a higher chance of being discussed at the preoperative (OR 1.39 95%CI 1.28-1.51) and postoperative MDT (OR 1.41 95%CI 1.30-1.53), receiving neoadjuvant (OR 1.15 95%CI 1.06-1.25) and adjuvant treatment (OR 2.04 95%CI 1.88-2.20). Higher education level increased the odds of MDT discussion but was not associated with oncological treatment. The proportion of patients discussed at the MDT increased, with almost all patients discussed since 2016. Despite this, treatment differences remained when patients diagnosed since 2016 were analysed separately. CONCLUSION: There were significant differences in how patients with different SES were treated for colorectal cancer. Further action is required to investigate the drivers of these differences as well as their impact on mortality and, ultimately, eliminate the inequalities.

Including uncertainty of the expected mortality rates in the prediction of loss in life expectancy.

PURPOSE: This study introduces a novel method for estimating the variance of life expectancy since diagnosis (LEC) and loss in life expectancy (LLE) for cancer patients within a relative survival framework in situations where life tables based on the entire general population are not accessible. LEC and LLE are useful summary measures of survival in population-based cancer studies, but require information on the mortality in the general population. Our method addresses the challenge of incorporating the uncertainty of expected mortality rates when using a sample from the general population. METHODS: To illustrate the approach, we estimated LEC and LLE for patients diagnosed with colon and breast cancer in Sweden. General population mortality rates were based on a random sample drawn from comparators of a matched cohort. Flexible parametric survival models were used to model the mortality among cancer patients and the mortality in the random sample from the general population. Based on the models, LEC and LLE together with their variances were estimated. The results were compared with those obtained using fixed expected mortality rates. RESULTS: By accounting for the uncertainty of expected mortality rates, the proposed method ensures more accurate estimates of variances and, therefore, confidence intervals of LEC and LLE for cancer patients. This is particularly valuable for older patients and some cancer types, where underestimation of the variance can be substantial when the entire general population data are not accessible. CONCLUSION: The method can be implemented using existing software, making it accessible for use in various cancer studies. The provided example of Stata code further facilitates its adoption.

Improving communication of cancer survival statistics-feasibility of implementing model-based algorithms in routine publications.

BACKGROUND: Routine reporting of cancer patient survival is important, both to monitor the effectiveness of health care and to inform about prognosis following a cancer diagnosis. A range of different survival measures exist, each serving different purposes and targeting different audiences. It is important that routine publications expand on current practice and provide estimates on a wider range of survival measures. We examine the feasibility of automated production of such statistics. METHODS: We used data on 23 cancer sites obtained from the Cancer Registry of Norway (CRN). We propose an automated way of estimating flexible parametric relative survival models and calculating estimates of net survival, crude probabilities, and loss in life expectancy across many cancer sites and subgroups of patients. RESULTS: For 21 of 23 cancer sites, we were able to estimate survival models without assuming proportional hazards. Reliable estimates of all desired measures were obtained for all cancer sites. DISCUSSION: It may be challenging to implement new survival measures in routine publications as it can require the application of modeling techniques. We propose a way of automating the production of such statistics and show that we can obtain reliable estimates across a range of measures and subgroups of patients.

Reranking cancer mortality using years of life lost.

Incidence and mortality are default measures to describe cancer trends. Mortality compounds incidence and survival but not age at death. We calculated years of life lost (YLL) due to 1 of the 10 solid tumors causing most deaths (lung, colorectal, prostate, pancreatic, breast, hepatobiliary, urinary, central nervous system, gastric, melanoma) using Swedish National Cancer and Cause of Death Registers. Comparing YLL with mortality in 2019, lung (43 152 YLL) and colorectal (32 340 YLL) cancer remained at the top, pancreatic cancer was upranked fourth to third (22 592 YLL) and breast cancer fifth to fourth (21 810 YLL), while prostate cancer was downranked third to fifth (17 380 YLL). Assessing YLL over 2010-2019, women lost consistently more life years because of lung and pancreatic cancer. A downward colorectal cancer mortality trend was reflected as a YLL decline only in women. YLL is simple to calculate, is intuitive to interpret, and expands the understanding of the cancer burden on society.

Exploring different research questions via complex multi-state models when using registry-based repeated prescriptions of antidepressants in women with breast cancer and a matched population comparison group.

BACKGROUND: Multi-state models are used to study several clinically meaningful research questions. Depending on the research question of interest and the information contained in the data, different multi-state structures and modelling choices can be applied. We aim to explore different research questions using a series of multi-state models of increasing complexity when studying repeated prescriptions data, while also evaluating different modelling choices. METHODS: We develop a series of research questions regarding the probability of being under antidepressant medication across time using multi-state models, among Swedish women diagnosed with breast cancer (n = 18,313) and an age-matched population comparison group of cancer-free women (n = 92,454) using a register-based database (Breast Cancer Data Base Sweden 2.0). Research questions were formulated ranging from simple to more composite ones. Depending on the research question, multi-state models were built with structures ranging from simpler ones, like single-event survival analysis and competing risks, up to complex bidirectional and recurrent multi-state structures that take into account the recurring start and stop of medication. We also investigate modelling choices, such as choosing a time-scale for the transition rates and borrowing information across transitions. RESULTS: Each structure has its own utility and answers a specific research question. However, the more complex structures (bidirectional, recurrent) enable accounting for the intermittent nature of prescribed medication data. These structures deliver estimates of the probability of being under medication and total time spent under medication over the follow-up period. Sensitivity analyses over different definitions of the medication cycle and different choices of timescale when modelling the transition intensity rates show that the estimates of total probabilities of being in a medication cycle over follow-up derived from the complex structures are quite stable. CONCLUSIONS: Each research question requires the definition of an appropriate multi-state structure, with more composite ones requiring such an increase in the complexity of the multi-state structure. When a research question is related with an outcome of interest that repeatedly changes over time, such as the medication status based on prescribed medication, the use of novel multi-state models of adequate complexity coupled with sensible modelling choices can successfully address composite, more realistic research questions.

Seasonal effects on cancer incidence and prognosis.

BACKGROUND: It is unknown if the reduction in the expected number of cancer cases diagnosed during Swedish holidays are due to diagnostic delays, how different cancers are affected, and if the season of diagnosis influences long-term cancer survival. We aimed to quantify seasonal trends in incidence and excess mortality for a wide range of malignancies, requiring more or less urgent clinical management. MATERIAL AND METHODS: This nationwide cohort study included all Swedish residents aged 20-84 in 1990-2019. Incidence and relative survival in pancreatic, colorectal, lung, urothelial, breast, and prostate cancer, together with malignant melanoma, non-Hodgkin lymphoma, and acute leukemia diagnosed during holiday and post-holiday were compared to working (reference) season. Incidence rate ratios (IRR) were estimated using Poisson regression and excess (cancer) mortality rate ratios using flexible parametric models. RESULTS: We identified 882,980 cancer cases. Incidence declined during holiday season for all malignancies and the IRR ranged from 0.58 (95% CI 0.57-0.59 in breast to 0.92 (95% CI 0.89-0.94) in pancreatic cancer. A post-holiday increase was noted for acute leukemia, pancreatic, and lung cancer. For all malignancies except lung cancer, non-Hodgkin lymphoma, and acute leukemia, the excess mortality at 2 years from diagnosis was higher among those diagnosed during the holiday season. A tendency toward elevated short-term (0.5 years) excess mortality was noted in the post-holiday group, but long-term effects only persisted in breast cancer. CONCLUSION: This study demonstrates lower holiday detection rates and higher mortality rates in various cancer types diagnosed during holiday season. Healthcare systems should offer a uniform level of cancer care independent of calendar season.

Association of metformin use and survival in patients with cutaneous melanoma and diabetes.

BACKGROUND: Metformin use has been associated with improved survival in patients with different types of cancer, but research regarding the effect of metformin on cutaneous melanoma (CM) survival is sparse and inconclusive. OBJECTIVES: To investigate the association between metformin use and survival among patients with CM and diabetes. METHODS: All adult patients with a primary invasive CM between 2007 and 2014 were identified in the Swedish Melanoma Registry and followed until death, or end of follow-up on 31 December 2017 in this population-based cohort study. Patients with both CM and type 2 diabetes mellitus were assessed further. Overall survival (OS) and melanoma-specific survival (MSS) were the primary endpoints. Cox proportional hazard models estimating crude and adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were used comparing peridiagnostic use vs. nonuse of metformin. Dose response was evaluated based on defined daily doses. RESULTS: Among a total of 23 507 patients, 1162 patients with CM and type 2 diabetes mellitus were included in the final cohort, with a median follow-up time of 4.1 years (interquartile range 2.4-6.1). Peridiagnostic metformin use was associated with a significantly decreased risk of death by any cause (HR 0.68, 95% CI 0.57-0.81). Cumulative pre- and postdiagnostic metformin use was also associated with improved OS: the HR for prediagnostic use was 0.90 (95% CI 0.86-0.95) for every 6 months of use and the HR for postdiagnostic use ranged from 0.98 (95% CI 0.97-0.98) for 0-6 months to 0.59 (0.49-0.70) for 24-30 months of use. No association was found for metformin use and MSS. CONCLUSIONS: Metformin use was associated with improved OS in patients with CM and diabetes regardless of timing (pre-, post- or peridiagnostic use) and followed a dose-response pattern. However, further research regarding the underlying mechanisms is warranted.

Age-specific survival trends and life-years lost in women with breast cancer 1990-2016: the NORDCAN survival studies.

BACKGROUND: A recent overview of cancer survival trends 1990-2016 in the Nordic countries reported continued improvements in age-standardized breast cancer survival among women. The aim was to estimate age-specific survival trends over calendar time, including life-years lost, to evaluate if improvements have benefited patients across all ages in the Nordic countries. METHODS: Data on breast cancers diagnosed 1990-2016 in Denmark, Finland, Iceland, Norway, and Sweden were obtained from the NORDCAN database. Age-standardized and age-specific relative survival (RS) was estimated using flexible parametric models, as was reference-adjusted crude probabilities of death and life-years lost. RESULTS: Age-standardized period estimates of 5-year RS in women diagnosed with breast cancer ranged from 87% to 90% and 10-year RS from 74% to 85%. Ten-year RS increased with 15-18 percentage points from 1990 to 2016, except in Sweden (+9 percentage points) which had the highest survival in 1990. The largest improvements were observed in Denmark, where a previous survival disadvantage diminished. Most recent 5-year crude probabilities of cancer death ranged from 9% (Finland, Sweden) to 12% (Denmark, Iceland), and life-years lost from 3.3 years (Finland) to 4.6 years (Denmark). Although survival improvements were consistent across different ages, women aged ≥70 years had the lowest RS in all countries. Period estimates of 5-year RS were 94-95% in age 55 years and 84-89% in age 75 years, while 10-year RS were 88-91% in age 55 years and 69-84% in age 75 years. Women aged 40 years lost on average 11.0-13.8 years, while women lost 3.8-6.0 years if aged 55 and 1.9-3.5 years if aged 75 years. CONCLUSIONS: Survival for Nordic women with breast cancer improved from 1990 to 2016 in all age groups, albeit with larger country variation among older women where survival was also lower. Women over 70 years of age have not had the same survival improvement as women of younger age.

Modelling multiple time-scales with flexible parametric survival models.

BACKGROUND: There are situations when we need to model multiple time-scales in survival analysis. A usual approach in this setting would involve fitting Cox or Poisson models to a time-split dataset. However, this leads to large datasets and can be computationally intensive when model fitting, especially if interest lies in displaying how the estimated hazard rate or survival change along multiple time-scales continuously. METHODS: We propose to use flexible parametric survival models on the log hazard scale as an alternative method when modelling data with multiple time-scales. By choosing one of the time-scales as reference, and rewriting other time-scales as a function of this reference time-scale, users can avoid time-splitting of the data. RESULT: Through case-studies we demonstrate the usefulness of this method and provide examples of graphical representations of estimated hazard rates and survival proportions. The model gives nearly identical results to using a Poisson model, without requiring time-splitting. CONCLUSION: Flexible parametric survival models are a powerful tool for modelling multiple time-scales. This method does not require splitting the data into small time-intervals, and therefore saves time, helps avoid technological limitations and reduces room for error.

Cardiovascular, bone, and metabolic health in men with castrate-resistant prostate cancer treated with androgen deprivation: a matched cohort study.

BACKGROUND: Descriptive data on late effects associated with castrate-resistant prostate cancer (CRPC) are sparse. We aimed to define the timing and incidence of cardiovascular disease (CVD), fractures, and diabetes in a patient population with CRPC. METHODS: In the population-based STHLM0 cohort 1464 men with CRPC were identified and matched with three men free from prostate cancer (PC) in the Stockholm region of Sweden. Kaplan-Meier estimates of net survival were used to describe time to CVD, fracture, and diabetes. Cox regression was used to compare incidence rates (IRRs) for the respective late effects. Cumulative incidence analyses of late effects in the presence of the competing risk of death were performed to estimate absolute risks. RESULTS: The Kaplan Meier estimates demonstrated a higher net probability for CVD, fracture, and diabetes among men diagnosed with CRPC compared to the matched comparators. The IRRs were 1.94 (95% CI: 1.79-2.12) for CVD, 2.08 (95% CI: 1.70-2.53) for fracture, and 2.00 (95% CI: 1.31-3.05) for diabetes, respectively, comparing men diagnosed with CRPC to men free from PC. The cumulative incidence of CVD at 12 months of follow-up was higher in men diagnosed with CRPC compared to healthy controls regardless of age with a difference in cumulative incidence being 0.20 for men aged <65 and 0.11 for men aged >84. CONCLUSIONS: In this cohort, the incidence of CVD was significantly higher among men with CRPC compared to healthy controls. Despite having this end-stage disease this finding proves that clinicians must recognize this late effect in men diagnosed with CRPC to improve preventive actions. These men did not have a higher absolute risk of fractures and diabetes after accounting for deaths due to any cause compared to healthy controls.

Standardised survival probabilities: a useful and informative tool for reporting regression models for survival data.

BACKGROUND: When interested in studying the effect of a treatment (or other exposure) on a time-to-event outcome, the most popular approach is to estimate survival probabilities using the Kaplan-Meier estimator. In the presence of confounding, regression models are fitted, and results are often summarised as hazard ratios. However, despite their broad use, hazard ratios are frequently misinterpreted as relative risks instead of relative rates. METHODS: We discuss measures for summarising the analysis from a regression model that overcome some of the limitations associated with hazard ratios. Such measures are the standardised survival probabilities for treated and untreated: survival probabilities if everyone in the population received treatment and if everyone did not. The difference between treatment arms can be calculated to provide a measure for the treatment effect. RESULTS: Using publicly available data on breast cancer, we demonstrated the usefulness of standardised survival probabilities for comparing the experience between treated and untreated after adjusting for confounding. We also showed that additional important research questions can be addressed by standardising among subgroups of the total population. DISCUSSION: Standardised survival probabilities are a useful way to report the treatment effect while adjusting for confounding and have an informative interpretation in terms of risk.

Pregnancy and childbirth outcomes in women with myeloproliferative neoplasms-a nationwide population-based study of 342 pregnancies in Sweden.

Pregnancy and childbirth in women with myeloproliferative neoplasms (MPN) are reported to be associated with maternal thrombosis, hemorrhage, and placental dysfunction. To assess the risks of adverse events in pregnancy in women with MPN, we performed a large population-based study using Swedish health care registers, and included all pregnancies that had reached gestational week 22 (prior to 2008, week 28) during the years 1973-2017 in women with MPN. Control pregnancies were matched 1:1 for age, calendar year, and parity. We identified 342 pregnancies in 229 women with MPN. Preterm birth was significantly increased in pregnancies in MPN, 14% compared to 4% of pregnancies in controls (p < 0.001). Correspondingly, low birth weight (<2500 g) was also significantly increased in MPN pregnancies (p = 0.042). Stillbirth was rare, with two events (0.6%) in MPN, none in controls. Maternal thrombotic complications occurred in three (1%) of the pregnancies in MPN patients, compared to none in controls. Pregnancy-related bleeding affected 14% of pregnancies in MPN and 9% in controls (p < 0.110). Cesarean section was significantly more common in pregnancies in MPN. Incidence was 12.2 per 100.000 pregnancies. In summary, preterm birth was an important complication in MPN pregnancies, while maternal complications were less common than previously reported.