Comparing Survival Extrapolation within All-Cause and Relative Survival Frameworks by Standard Parametric Models and Flexible Parametric Spline Models Using the Swedish Cancer Registry

BACKGROUND

In health technology assessment, restricted mean survival time and life expectancy are commonly evaluated. Parametric models are typically used for extrapolation. Spline models using a relative survival framework have been shown to estimate life expectancy of cancer patients more reliably; however, more research is needed to assess spline models using an all-cause survival framework and standard parametric models using a relative survival framework.

AIM

To assess survival extrapolation using standard parametric models and spline models within relative survival and all-cause survival frameworks.

METHODS

From the Swedish Cancer Registry, we identified patients diagnosed with 5 types of cancer (colon, breast, melanoma, prostate, and chronic myeloid leukemia) between 1981 and 1990 with follow-up until 2020. Patients were categorized into 15 cancer cohorts by cancer and age group (18-59, 60-69, and 70-99 y). We right-censored the follow-up at 2, 3, 5, and 10 y and fitted the parametric models within an all-cause and a relative survival framework to extrapolate to 10 y and lifetime in comparison with the observed Kaplan-Meier survival estimates. All cohorts were modeled with 6 standard parametric models (exponential, Weibull, Gompertz, log-logistic, log-normal, and generalized gamma) and 3 spline models (on hazard, odds, and normal scales).

RESULTS

For predicting 10-y survival, spline models generally performed better than standard parametric models. However, using an all-cause or a relative survival framework did not show any distinct difference. For lifetime survival, extrapolating from a relative survival framework agreed better with the observed survival, particularly using spline models.

CONCLUSIONS

For extrapolation to 10 y, we recommend spline models. For extrapolation to lifetime, we suggest extrapolating in a relative survival framework, especially using spline models.

HIGHLIGHTS

For survival extrapolation to 10 y, spline models generally performed better than standard parametric models did. However, using an all-cause or a relative survival framework showed no distinct difference under the same parametric model.Survival extrapolation to lifetime within a relative survival framework agreed well with the observed data, especially using spline models.Extrapolating parametric models within an all-cause survival framework may overestimate survival proportions at lifetime; models for the relative survival approach may underestimate instead.

Vulvar cancer incidence and net survival in Sweden 1960 to 2019: A population-based national study

INTRODUCTION

Vulvar cancer is a rare gynecological cancer affecting mostly older women. The aim of this population-based study was to investigate the incidence and net survival of vulvar cancer in Swedish women from 1960 to 2019.

MATERIAL AND METHODS

Data were retrieved from the mandatory Swedish Cancer Registry consisting of all women diagnosed with vulvar cancer between 1960 and 2019. Only women with a morphologically verified diagnosis of vulvar cancer were included. The individuals were then further matched with the Swedish Death Registry up until May 31, 2020.

RESULTS

In total, 8499 women were included with the following morphologies: squamous cell carcinoma 7250 (85.8%), malignant melanoma 539 (6.4%), adenocarcinoma 401 (4.8%) and other: 259 (3.1%). More than 50% of vulvar cancer cases occurred in women aged between 65 and 84 years of age. The 5-year age-standardized net survival increased from 53.0% (95% confidence interval [CI] 48.9-57.5) in 1960 to 72.1% (95% CI 68.8-75.5) in 2019. The proportion of adenocarcinoma among all cases increased from 2.0% to 8.7% between the 1960s and 2010s and an increase in age-standardized 5-year net survival was found for adenocarcinoma.

CONCLUSIONS

The age-standardized incidence of vulvar cancer cases in Sweden was stable between 1960 and 2019. During the study period, an increase in adenocarcinoma and a decrease in malignant melanoma cases was found. Five-year net survival increased by 20 percent units during the study period. For squamous cell carcinoma, an increased age-specific 5-year net survival was observed for all age groups, apart for women aged ≥85.

Comparing the diagnostic accuracy, reading time, and inter-rater agreement of breast MRI abbreviated and full protocols: a multi-reader study

BACKGROUND

Earlier studies have shown that abbreviated protocol magnetic resonance imaging (AB-MRI) has similar diagnostic accuracy as the full protocol (Full MRI).

PURPOSE

To compare the diagnostic accuracy, reading time, and inter-rater agreement of AB-MRI to Full MRI among women without known increased familial risk of breast cancer or prior biopsy.

MATERIAL AND METHODS

In total, 395 MRI examinations were included in this study. Three readers were blinded to all patient information. The AB-MRI and Full MRI were read separately and in a different random order for each of the readers. Scores 1-2 were considered test negative while scores 3-5 were test positive. A positive reference test was the diagnosis of malignancy; a negative reference test was the absence of a diagnosis of breast cancer within a two-year follow-up. We used a generalized estimating equations approach to compare sensitivity and specificity between the two protocols. We used t-tests to compare the average reading time and Krippendorff's alpha to compare inter-rater agreement.

RESULTS

MRI examinations of 395 women (median age=56 years) were evaluated. For AB-MRI and Full MRI, respectively, the sensitivity was 93.0% (95% CI=90.6-95.0) vs. 92.0% (95% CI=89.4-94.1), the specificity was 91.7% (95% CI=90.3-92.9) vs. 94.3% (95% CI=93.2-95.3), average reading time was 67 vs. 126 s, and the inter-rater agreement 0.79 vs. 0.83. The difference in sensitivity was not statistically significant (P=0.840), but the difference in specificity was significant (P=0.003).

CONCLUSION

AB-MRI has similar sensitivity, but somewhat lower specificity. The average reading time for the abbreviated protocol is lower, as is inter-rater agreement.

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.

Increased incidence and improved survival in endometrial cancer in Sweden 1960-2014: a population-based registry survey

BACKGROUND

An investigation of trends of incidence and net survival (NS) for endometrial cancer in Sweden.

METHODS

Morphologically verified endometrial carcinoma diagnosed 1960 to 2014 were collected from the nation-wide Swedish Cancer Registry. Endometrial cancer patients were assessed with regards to time trends for incidence and 54,825 cases remained for survival analyses. Cases diagnosed 1995 to 2014 were categorized according to detailed morphology and from 2005 to 2014 FIGO stage was also categorized.

RESULTS

There was a trend of increasing incidence of endometrial carcinoma for women above 55 years of age. NS was improved at 5- and 10-year follow-up. The 5-year net survival in 2010-2014 was 86%. The most prominent improvement in NS was found in the elderly women above 75 years of age.

CONCLUSIONS

This study observed increased incidence of endometrial cancer in Sweden from 1960 to 2014. The progress in diagnostics and treatment, seem to have improved the net survival, especially in elderly women.

Current clinical practice in the management of phyllodes tumors of the breast: an international cross-sectional study among surgeons and oncologists

PURPOSE

Phyllodes tumors of the breast are rare fibroepithelial lesions that are classified as benign, borderline or malignant. There is little consensus on best practice for the work-up, management, and follow-up of patients with phyllodes tumors of the breast, and evidence-based guidelines are lacking.

METHODS

We conducted a cross-sectional survey of surgeons and oncologists with the aim to describe current clinical practice in the management of phyllodes tumors. The survey was constructed in REDCap and distributed between July 2021 and February 2022 through international collaborators in sixteen countries across four continents.

RESULTS

A total of 419 responses were collected and analyzed. The majority of respondents were experienced and worked in a university hospital. Most agreed to recommend a tumor-free excision margin for benign tumors, increasing margins for borderline and malignant tumors. The multidisciplinary team meeting plays a major role in the treatment plan and follow-up. The vast majority did not consider axillary surgery. There were mixed opinions on adjuvant treatment, with a trend towards more liberal regiments in patients with locally advanced tumors. Most respondents preferred a five-year follow-up period for all phyllodes tumor types.

CONCLUSIONS

This study shows considerable variation in clinical practice managing phyllodes tumors. This suggests the potential for overtreatment of many patients and the need for education and further research targeting appropriate surgical margins, follow-up time and a multidisciplinary approach. There is a need to develop guidelines that recognize the heterogeneity of phyllodes tumors.

Survival in Swedish patients with systemic sclerosis: a nationwide population-based matched cohort study

OBJECTIVES

To conduct the first-ever nationwide, population-based cohort study investigating survival patterns of all patients with incident SSc in Sweden compared with matched individuals from the Swedish general population.

METHODS

We used the National Patient Register to identify patients with incident SSc diagnosed between 2004 and 2015 and the Total Population Register to identify comparators (1:5), matched on sex, birth year and residential area. We followed them until death, emigration or the end of 2016. Follow-up of the general population comparators started the same date as their matched patients were included. We estimated all-cause survival using the Kaplan-Meier method, crude mortality rates and hazard ratios (HRs) using flexible parametric models.

RESULTS

We identified 1139 incident patients with SSc and 5613 matched comparators. The median follow-up was 5.0 years in patients with SSc and 6.0 years for their comparators. During follow-up, 268 deaths occurred in patients with SSc and 554 in their comparators. The 5-year survival was 79.8% and the 10-year survival was 67.7% among patients with SSc vs 92.9% and 84.8%, respectively, for the comparators (P < 0.0001). The mortality rate in patients with SSc was 42.1 per 1000 person-years and 15.8 per 1000 person-years in their comparators, corresponding to an HR of 3.7 (95% CI 2.9, 4.7) at the end of the first year of follow-up and 2.0 (95% CI 1.4, 2.8) at the end of the follow-up period.

CONCLUSION

Despite advances in understanding the disease and in diagnostic methods over the past decades, survival is still severely impacted in Swedish patients diagnosed with SSc between 2004 and 2015.

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.

Time Trends for Incidence and Net Survival of Cervical Cancer in Sweden 1960-2014-A Nationwide Population-Based Study

BACKGROUND

The aim was to investigate time trends for incidence and long-term net survival in the morphologic subtypes and stages of cervical cancer in Sweden during the period 1960 to 2014.

METHODS

Women with invasive cervical cancer were identified through the Swedish Cancer Registry. Incidence and net survival were calculated according to morphology, age at diagnosis, and FIGO stage at diagnosis.

RESULTS

In total, 29,579 cases of invasive cervical cancer between 1960 and 2014 were included. The age-standardized incidence for squamous cell carcinoma (SCC) decreased until 2000; thereafter, the incidence rate stagnated, and a small increase was found in 2014. The incidence of adenocarcinoma continuously increased. The age-standardized 5-year net survival increased. However, decreasing net survival with increasing age was found. A higher stage at diagnosis showed a worse net survival. SCC and adenocarcinoma did not statistically differ as regards net survival in the last years of the study.

CONCLUSIONS

Age-standardized 5-year net survival improved between 1960 and 2014. A positive trend for short- and long-term net survival was seen for women ages 18 to 64 years but long-term net survival for women ≥75 years decreased. In this study, age and FIGO stage at diagnosis were found to be important prognostic factors in determining net survival. The morphologies, SCC, and adenocarcinoma did not statistically differ as regards net survival in the last years of the study.

IMPACT

This study demonstrates longitudinal data on cervical cancer in Sweden for over 50 years with sub analyses on morphology, age, and stage at diagnosis.

Reproductive history, as measured by parity, age at first birth and sex of offspring, and cancer-specific survival after a haematological malignancy

BACKGROUND

Overall, women have better cancer-specific survival than men following haematological malignancies. The effect of reproductive factors on prognosis in women remains unknown and population-based studies are needed.

MATERIAL AND METHODS

A nationwide cohort of 21,237 Swedish women with a recorded haematological malignancy at ages 18-69 years was identified in the Swedish Cancer Register 1970-2018. Pre-diagnosis childbirths for each woman were linked to the Swedish Multigeneration Register. Net survival and excess hazard ratios for parity, age at first birth, time since the latest birth, and sex of offspring were estimated using flexible parametric models adjusted for age, year, and educational level.

RESULTS

In unadjusted analyses, parity (p = 0.0012) and high age at first birth (p < 0.0001) were associated with better survival. After co-adjustments for reproductive factors and confounders, the associations were attenuated. The adjusted association with parity was mainly observed among women aged above 40 years at diagnosis (p = 0.0033). The associations with reproductive factors were non-significant across subtypes of haematological malignancy. There was a tendency of higher excess mortality for an increasing number of boys compared to girls, although only significant for women with three or more children (p = 0.0126).

CONCLUSION

Reproductive factors were in part associated with survival following diagnosis of a haematological malignancy. However, the effect sizes were small with inconsistent association patterns, and thus reproductive factors may only partly contribute to the survival advantage of women over men.

Cancer outcomes research - a European challenge Part II: Opportunities and priorities

In Part I of our review of cancer outcome research, we analysed pros and cons of various measures relevant to quantifying the burden of cancer. Based on our recommendations in Part I, we now discuss in Part II opportunities and priorities in four areas of outcome research: primary prevention; early detection screening; treatment; and quality‐of‐life assessment. We recommend the establishment of an infrastructure that facilitates high‐quality research in these areas: (a) progress in primary prevention can be assessed most directly by monitoring cancer incidence although the interpretation of temporal trends is notoriously confounded by numerous factors that complicate causal inference. (b) preventive screening, with the aim to prevent advanced disease, appears to work well in in some tumours but not in others. It will require randomized control trials (RCTs) to quantify benefits and harms although conclusive studies are increasingly difficult to undertake. We therefore propose learning screening programmes (randomization at the time of rolling out population‐based programmes) as the most feasible approach. (c) New therapeutic interventions tailored to the individual patient often require assessment in RCTs with rather complex and dynamic structure, making their design and analyses increasingly challenging but also more suited to be executed as academic, PI‐initiated trials. (d) We next discuss assessment of quality‐of‐life aspects. Quality of life is a neglected component in outcome research with an urgent need for development, validation and standardization. We finally recommend four initiatives that would pave the way for a valid and informative assessment of the goals for improved cancer control in Europe as defined by the European Academy of Cancer Sciences.

Survival, causes of death, and the prognostic role of comorbidities in chronic lymphocytic leukemia in the pre-ibrutinib era: A population-based study

OBJECTIVE

To evaluate temporal trends in survival and causes of death in patients with chronic lymphocytic leukemia (CLL) in a nationwide study.

METHODS

The cohort consisted of 13,009 Swedish CLL patients diagnosed 1982-2013. Relative survival (RS) and excess mortality rate ratios (EMRR) with 95% confidence intervals (95% CIs) were estimated using flexible parametric survival models. Cause-specific hazard ratios (HRs) were estimated for the linear effect of 10-year increase in year of diagnosis.

RESULTS

The excess mortality decreased comparing 2003-2013 to 1982-1992 (EMRR = 0.53, 95% CI 0.48-0.58). The 5-year RS increased between 1982 and 2012 for patients >51 years at diagnosis and improved for patients ≤51 years after 2002. The rate of CLL-specific deaths decreased over time (HR = 0.78, 95% CI 0.75-0.81). Compared to patients with no comorbidity, patients with 1 and 2+ Charlson Comorbidity Index points had HR = 1.35 (95% CI 1.25-1.45) and HR = 1.47 (95% CI 1.37-1.57) for CLL-related mortality, respectively.

CONCLUSION

Survival in CLL patients improved in the era of chemoimmunotherapy, and this was largely explained by reduced CLL-related mortality. The increased rate of CLL-related mortality in patients with comorbidities emphasizes the importance of the newer and better tolerated targeted therapy.

Comparison of Relative Survival and Cause-Specific Survival in Men With Prostate Cancer According to Age and Risk Category: A Nationwide, Population-Based Study

Net survival, estimated in a relative survival (RS) or cause-specific survival (CSS) framework, is a key measure of the effectiveness of cancer management. We compared RS and CSS in men with prostate cancer (PCa) according to age and risk category, using Prostate Cancer data Base Sweden, including 168,793 men younger than age 90 years, diagnosed 1998–2016 with PCa. RS and CSS were compared according to age and risk category based on TNM (tumor, nodes, and metastases) stage, Gleason score, and prostate-specific antigen level. Each framework requires assumptions that are unlikely to be appropriate for PCa. Ten-year RS was substantially higher than CSS in men aged 80–89 with low-risk PCa: 125% (95% confidence interval: 113, 138) versus 85% (95% confidence interval: 82, 88). In contrast, RS and CSS were similar for men under age 70 and for all men with regional or distant metastases. Both RS and CSS produce biased estimates of net survival for men with low- and intermediate-risk PCa, in particular for men over 80. Due to biases, net survival is overestimated in analysis of RS but underestimated in analysis of CSS. These results highlight the importance of evaluating the underlying assumptions for each method, because the “true” net survival is expected to lie between the limits of RS and CSS.

Cancer outcomes research-a European challenge: measures of the cancer burden

In a mission that aims to improve cancer control throughout Europe, the European Academy of Cancer Sciences has defined two key indicators of progress: within one to two decades, overall cancer-specific 10-year survival should reach 75%, and in each country, overall cancer mortality rates should be convincingly declining. To lay the ground for assessment of progress and to promote cancer outcomes research in general, we have reviewed the most common population-based measures of the cancer burden. We emphasize the complexities and complementary approaches to measure cancer survival and the novel opportunities for improved assessment of quality of life. We propose that: incidence and mortality rates are standardized to the European population; net survival is used as the measure of prognosis but with proper adjustments for confounding when temporal trends in overall cancer survival are assessed; and cancer-specific quality of life is measured by a combination of existing questionnaires and utilizes emerging communication technologies. We conclude that all measures are important and that a meaningful interpretation also requires a deep understanding of the larger clinical and public health context.

Incidence and survival of epithelial ovarian, fallopian tube, peritoneal, and undesignated abdominal/pelvic cancers in Sweden 1960-2014: A population-based cohort study

Background

Despite improved surgical and oncological treatment, ovarian cancer continues to be the most lethal of the gynecologic malignancies. We aimed to analyze survival trends in epithelial ovarian cancer with regard to age, tumor site, and morphology in Sweden 1960 to 2014.

Methods

A nationwide population-based study was conducted using data from the Swedish Cancer Registry on 46,350 women aged 18 or older with a diagnosis of epithelial ovarian, fallopian tube, peritoneal, or undesignated abdominal/pelvic cancer 1960 to 2014. Analyses of age-standardized incidence and relative survival (RS) were performed and time trends modelled according to age, tumor site, and morphology.

Results

Overall incidence of ovarian, tubal, peritoneal, and undesignated abdominal/pelvic cancers declined since 1980. Median age at diagnosis increased. Serous carcinoma increased in incidence. RS at 1, 2 and 5 years from diagnosis improved since 1960, although not for the youngest and the oldest patients. Ten-year RS did not improve. The best RS was found for fallopian tube cancer and the worst RS for undesignated abdominal/pelvic cancer. Among the morphologic subgroups, endometrioid carcinoma had the best RS.

Conclusions

Survival in epithelial ovarian, tubal, peritoneal, and undesignated abdominal/pelvic cancers in Sweden has improved over the last six decades. Advances in epithelial ovarian cancer treatment have extended life for the first 5 years from diagnosis but 10-year survival remains poor.

Temporal improvements noted in life expectancy of patients with colorectal cancer; a Dutch population-based study

OBJECTIVE

Specific survival estimates are needed for the increasing number of colorectal cancer (CRC) survivors. The aim of this population-based study was to determine conditional loss in expectation of life (LEL) due to CRC.

STUDY DESIGN AND SETTING

All surgically treated patients with CRC registered in the Netherlands Cancer Registry with stage I-III between 1990-2016, were included (N = 203,216). Estimates of conditional LEL were predicted using flexible parametric models and the total life years lost due to cancer were estimated.

RESULTS

LEL decreased with older age and patients with rectal cancer or higher disease stage had highest LEL. In 2010, LEL for sixty-year old male and female patients was 2 vs. 2, 4 vs. 4, and 7 vs. 8 years for colon cancer, and 2 vs. 2, 4 vs. 5 and 7 vs. 8 years for rectal cancer, respectively. Conditional LEL in patients with CRC decreased during follow-up. Patients with combined stage I-III colon and rectal cancer in 2010 lost an estimated 18,628 and 11,336 life years.

CONCLUSION

This study quantified the impact of CRC on patient's life expectancy, both on individual and population level and demonstrated temporal improvements in CRC survival. These results provide meaningful information that can be used during follow-up.

A multistate model incorporating estimation of excess hazards and multiple time scales

As cancer patient survival improves, late effects from treatment are becoming the next clinical challenge. Chemotherapy and radiotherapy, for example, potentially increase the risk of both morbidity and mortality from second malignancies and cardiovascular disease. To provide clinically relevant population-level measures of late effects, it is of importance to (1) simultaneously estimate the risks of both morbidity and mortality, (2) partition these risks into the component expected in the absence of cancer and the component due to the cancer and its treatment, and (3) incorporate the multiple time scales of attained age, calendar time, and time since diagnosis. Multistate models provide a framework for simultaneously studying morbidity and mortality, but do not solve the problem of partitioning the risks. However, this partitioning can be achieved by applying a relative survival framework, allowing us to directly quantify the excess risk. This article proposes a combination of these two frameworks, providing one approach to address (1) to (3). Using recently developed methods in multistate modeling, we incorporate estimation of excess hazards into a multistate model. Both intermediate and absorbing state risks can be partitioned and different transitions are allowed to have different and/or multiple time scales. We illustrate our approach using data on Hodgkin lymphoma patients and excess risk of diseases of the circulatory system, and provide user-friendly Stata software with accompanying example code.

Frequent platelet donation is associated with lymphopenia and risk of infections: A nationwide cohort study

BACKGROUND

Recently, plateletpheresis donations using a widely used leukoreduction system (LRS) chamber have been associated with T-cell lymphopenia. However, clinical health consequences of plateletpheresis-associated lymphopenia are still unknown.

STUDY DESIGN AND METHODS

A nationwide cohort study using the SCANDAT3-S database was conducted with all platelet- and plasmapheresis donors in Sweden between 1996 and 2017. A Cox proportional hazards model, using donations as time-dependent exposures, was used to assess the risk of infections associated with plateletpheresis donations using an LRS chamber.

RESULTS

A total of 74 408 apheresis donors were included. Among donors with the same donation frequency, plateletpheresis donors using an LRS chamber were at an increased risk of immunosuppression-related infections and common bacterial infections in a dose-dependent manner. While very frequent donors and infections were rare in absolute terms resulting in wide confidence intervals (CIs), the increased risk was significant starting at one-third or less of the allowed donation frequency in a 10-year exposure window, with hazard ratios reaching 10 or more. No plateletpheresis donors that used an LRS chamber experienced a Pneumocystis jirovecii, aspergillus, disseminated mycobacterial, or cryptococcal infection. In a subcohort (n = 42), donations with LRS were associated with low CD4+ T-cell counts (Pearson's R = -0.41; 95% CI, - 0.63 to -0.12).

CONCLUSION

Frequent plateletpheresis donation using an LRS chamber was associated with CD4+ T-cell lymphopenia and an increased risk of infections. These findings suggest a need to monitor T-lymphocyte counts in frequent platelet donors and to conduct future investigations of long-term donor health and for regulators to consider steps to mitigate lymphodepletion in donors.

Cancer survival statistics for patients and healthcare professionals - a tutorial of real-world data analysis

Monitoring survival of cancer patients using data collected by population-based cancer registries is an important component of cancer control. In this setting, patient survival is often summarized using net survival, that is survival from cancer if there were no other possible causes of death. Although net survival is the gold standard for comparing survival between groups or over time, it is less relevant for understanding the anticipated real-world prognosis of patients. In this review, we explain statistical concepts targeted towards patients, clinicians and healthcare professionals that summarize cancer patient survival under the assumption that other causes of death exist. Specifically, we explain the appropriate use, interpretation and assumptions behind statistical methods for competing risks, loss in life expectancy due to cancer and conditional survival. These concepts are relevant when producing statistics for risk communication between physicians and patients, planning for use of healthcare resources, or other applications when consideration of both cancer outcomes and the competing risks of death is required. To reinforce the concepts, we use Swedish population-based data of patients diagnosed with cancer of the breast, prostate, colon and chronic myeloid leukaemia. We conclude that when choosing between summary measures of survival it is critical to characterize the purpose of the study and to determine the nature of the hypothesis under investigation. The choice of terminology and style of reporting should be carefully adapted to the target audience and may range from summaries for specialist readers of scientific publications to interactive online tools aimed towards lay persons.

The association between breast cancer risk factors and background parenchymal enhancement at dynamic contrast-enhanced breast MRI

Background

Background parenchymal enhancement (BPE) of normal tissue at breast magnetic resonance imaging is suggested to be an independent risk factor for breast cancer. Its association with established risk factors for breast cancer is not fully investigated.

Purpose

To study the association between BPE and risk factors for breast cancer in a healthy, non-high-risk screening population.

Material and Methods

We measured BPE and mammographic density and used data from self-reported questionnaires in 214 healthy women aged 43–74 years. We estimated odds ratios for the univariable association between BPE and risk factors. We then fitted an adjusted model using logistic regression to evaluate associations between BPE (high vs. low) and risk factors, including mammographic breast density.

Results

The majority of women had low BPE (84%). In a multivariable model, we found statistically significant associations between BPE and age (P = 0.002) and BMI (P = 0.03). We did find a significant association between systemic progesterone medication and BPE, but due to small numbers, the results should be interpreted with caution. The adjusted odds ratio for high BPE was 3.1 among women with density D (compared to B) and 2.1 for density C (compared to B). However, the association between high BPE and density was not statistically significant. We did not find statistically significant associations with any other risk factors.

Conclusion

Our study confirmed the known association of BPE with age and BMI. Although our results show a higher likelihood for high BPE with increasing levels of mammographic density, the association was not statistically significant.

Conditional Survival and Cure of Patients With Colon or Rectal Cancer: A Population-Based Study

BACKGROUND

The increasing number of colorectal cancer (CRC) survivors need survival estimates that account for the time already survived. The aim of this population-based study was to determine conditional survival, cure proportions, and time-to-cure (TTC) of patients with colon or rectal cancer.

MATERIALS AND METHODS

All patients with pathologic stage I-III CRC treated with endoscopy or surgery, diagnosed and registered in the Netherlands Cancer Registry between 1995 and 2016, and aged 18 to 99 years were included. Conditional survival was calculated for those diagnosed before and after 2007. Cure proportions were calculated using flexible parametric models.

RESULTS

A total of 175,384 patients with pathologic stage I (25%), II (38%), or III disease (37%) were included. Conditional 5-year survival of patients with stage I, II, and III colon cancer having survived 5 years was 98%, 94%, and 92%, respectively. For patients with stage I-III rectal cancer, this was 96%, 89%, and 85%, respectively. Statistical cure in patients with colon cancer was reached directly after diagnosis (stage I) to 6 years (stage III) after diagnosis depending on age, sex, and disease stage. Patients with rectal cancer reached cure 0.5 years after diagnosis (stage I) to 9 years after diagnosis (stage III). In 1995, approximately 42% to 46% of patients with stage III colon or rectal cancer, respectively, were considered cured, whereas in 2016 this percentage increased to 73% to 78%, respectively.

CONCLUSIONS

The number of patients with CRC reaching cure has increased substantially over the years. This study's results provide valuable insights into trends of CRC patient survival and are important for patients, clinicians, and policymakers.

Incidence of myeloproliferative neoplasms - trends by subgroup and age in a population-based study in Sweden

BACKGROUND

The reported incidence of Philadelphia-negative myeloproliferative neoplasms (MPNs) differs substantially between previous reports, likely due to true regional differences in incidence and/or variations in the quality and coverage of the cancer registers.

OBJECTIVE

We therefore assessed MPN incidence in Sweden during recent years using prospectively collected information captured in Swedish health registers.

METHODS

Patients with MPNs were identified through the Swedish Cancer Register and Swedish Blood Cancer Register between 2000 and 2014. Information on the Swedish population was obtained from the Human Mortality Database. Crude and age-standardized incidence rates of MPNs with 95% confidence intervals (CIs) were calculated.

RESULTS

A total of 6281 MPN cases were reported to the Swedish Cancer Register and Swedish Blood Cancer Register during 2000-2014. The age-standardized, to the Swedish population in 2000, incidence for all MPNs was 4.45 (95% confidence interval [CI] 4.34-4.56)/100 000 person-years. The age-standardized incidence for polycythemia vera was 1.48 (1.42-1.54), for essential thrombocythemia 1.60 (1.53-1.66) and for primary myelofibrosis 0.52 (0.48-0.56)/100 000 person-years, respectively. The incidence rate of MPNs was substantially higher in the older compared to the younger age groups. The incidence increased during the study period, likely to do better reporting and increasing age of the general population.

CONCLUSION

The reported MPN incidences in our study, which were in the higher interval of previously published studies, are likely more accurate compared to previous reports due to the population-based setting and high level of coverage in the Swedish Cancer and Blood Cancer Registers.

Bladder cancer survival: Women only fare worse in the first two years after diagnosis

OBJECTIVES

It has consistently been shown that women who are diagnosed with bladder cancer have lower survival than men, but the exact mechanism remains unknown. Most studies assumed that the sex-specific mortality ratio is constant over time, possibly resulting in inaccurate estimates in various periods of follow-up. This study aimed to investigate the sex-specific excess mortality in bladder cancer patients and its variation over follow-up time.

METHODS

Observational cohort study. Using data from the population-based Netherlands Cancer Registry, we studied 24,169 patients diagnosed between 2003 and 2014 with histologically confirmed ≥T1 bladder cancer with follow-up until January 2018. We used flexible parametric relative survival models to estimate excess mortality as a function of time for each sex and to explore the effect of covariates on these functions.

RESULTS

Female patients (24%) had worse clinical tumor, node, and metastasis-stage at diagnosis and more often a nonurothelial tumor histology. The excess mortality ratio of sex was not constant over time; in the first two years after diagnosis excess mortality rates for women were higher than for men, but lower thereafter; this applied to both nonmuscle-invasive and muscle-invasive bladder cancer subgroups. Baseline differences in age, tumor, node, and metastasis-stage and histology accounted for only part of the excess mortality gap.

CONCLUSIONS

The assumption of proportional hazards over time leads to underestimation of the excess mortality ratio for women in the first two years and overestimation thereafter, when excess mortality is comparable for women and men. Clinicians should incorporate the initial sex-specific poorer outcome in their considerations regarding prognosis and treatment options for female patients, e.g., more invasive treatment and neo-adjuvant treatment. These findings also point towards a mechanism of micrometastatic disease, warranting assessment of sex-specific efficacy in randomized controlled trials on treatments in this patient population.

Does three-dimensional functional infrared imaging improve breast cancer detection based on digital mammography in women with dense breasts?

Purpose

We aimed to estimate the incremental cancer detection rate achieved by adding three-dimensional functional infrared imaging (3DIRI) to digital mammography in women with dense breasts.

Materials and methods

In this prospective study conducted between December 2014 and April 2016, 1727 women (median age 56) with percentage volumetric breast density > 6% were recruited at routine screening mammography to undergo additional 3DIRI. The 3DIRI findings were classified as negative or positive. Women with a negative mammography but positive 3DIRI were referred to dynamic contrast-enhanced MRI, whereas all other women underwent routine follow-up based on the mammography finding. Diagnosis of breast cancer was verified by histopathologic examination. The number of women diagnosed with a malignancy formed the basis of our statistical analysis.

Results

Mammography detected 7 cancers in 7 women. Of 1692 women with negative mammography, 222 women (13%) had a positive 3DIRI of which 219 underwent MRI. An additional 6 cancers were identified in 5 women, increasing the diagnostic yield from 7 of 1727 (0.41%) to 12 of 1727 (0.69%). The incremental cancer detection rate associated with using 3DIRI to select women for MRI was 5 of 222 (22.5 additional cancers per 1000).

Conclusion

The use of 3DIRI to select women for an additional MRI can result in the detection of additional cancers in women with dense breasts, but at the expense of additional false positives and considerably lower positive predictive value of the combined examinations. Additional studies are necessary to evaluate the role of 3DIRI as an adjunct to mammography.

Key Points

• Use of three-dimensional functional infrared imaging to select women for an MRI in addition to screening mammography has the potential to improve breast cancer detection in women with dense breasts.

Electronic supplementary material

The online version of this article (10.1007/s00330-019-06248-y) contains supplementary material, which is available to authorized users.

InterPreT cancer survival: A dynamic web interactive prediction cancer survival tool for health-care professionals and cancer epidemiologists

BACKGROUND

There are a variety of ways for quantifying cancer survival with each measure having advantages and disadvantages. Distinguishing these measures and how they should be interpreted has led to confusion among scientists, the media, health care professionals and patients. This motivates the development of tools to facilitate communication and interpretation of these statistics.

METHODS

"InterPreT Cancer Survival" is a newly developed, publicly available, online interactive cancer survival tool targeted towards health-care professionals and epidemiologists (http://interpret.le.ac.uk). It focuses on the correct interpretation of commonly reported cancer survival measures facilitated through the use of dynamic interactive graphics. Statistics presented are based on parameter estimates obtained from flexible parametric relative survival models using large population-based English registry data containing information on survival across 6 cancer sites; Breast, Colon, Rectum, Stomach, Melanoma and Lung.

RESULTS

Through interactivity, the tool improves understanding of various measures and how survival or mortality may vary by age and sex. Routine measures of cancer survival are reported, however, individualised estimates using crude probabilities are advocated, which is more appropriate for patients or health care professionals. The results are presented in various interactive formats facilitating understanding of individual risk and differences between various measures.

CONCLUSIONS

"InterPreT Cancer Survival" is presented as an educational tool which engages the user through interactive features to improve the understanding of commonly reported cancer survival statistics. The tool has received positive feedback from a Cancer Research UK patient sounding board and there are further plans to incorporate more disease characteristics, e.g. stage.

Contemporarily Treated Patients With Hodgkin Lymphoma Have Childbearing Potential in Line With Matched Comparators

Purpose With excellent cure rates for young patients with Hodgkin lymphoma (HL), there is an increasing number of female survivors of HL interested in becoming pregnant. Here, we report childbearing among contemporarily treated HL survivors in comparison with the general population. Material and Methods Using Swedish registers, 449 women (ages 18 to 40 years) diagnosed with HL between 1992 and 2009 and in remission 9 months after diagnosis were identified. Patients were age- and calendar-year-matched to 2,210 population comparators. Rates of first postdiagnosis childbirth were calculated. Hazard ratios (HRs) with 95% CIs were estimated for different follow-up periods using Cox regression. Cumulative probabilities of first childbirth were calculated in the presence of the competing risk of death or relapse. Results Twenty-two percent of relapse-free patients with HL had a child during follow-up, and first childbirth rates increased over time, from 40.2 per 1,000 person-years (1992 to 1997) to 69.7 per 1,000 person-years (2004 to 2009). For comparators, childbirth rates remained stable (70.1 per 1,000 person-years). Patients diagnosed between 2004 and 2009 had a cumulative probability of childbirth similar to comparators. Three years or more after diagnosis, no differences in childbirth rates were observed between patients and comparators, regardless of stage or treatment. Patients who received six to eight courses of bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone had a lower childbirth rate than comparators during the first 3 years (HR, 0.23; 95% CI, 0.06 to 0.94), as did patients who received six to eight courses of chemotherapy and radiotherapy (HR, 0.21; 95% CI, 0.07 to 0.65). Conclusion Childbearing potential among female survivors of HL has improved over time, and childbirth rates 3 years after diagnosis in contemporarily treated patients are, in the absence of relapse, similar to those in the general population, regardless of stage and treatment.

Greater attention should be paid to developing therapies for elderly patients with Hodgkin lymphoma-A population-based study from Sweden

OBJECTIVE

Forty percent of Hodgkin lymphoma (HL) patients are older than 50 years at diagnosis, a fact which is not commonly recognized. Older patients do significantly worse than younger patients and are rarely included in clinical trials.

METHODS

Using data from Swedish Cancer and Lymphoma Registries, we estimated relative survival ratios (RSRs) for 7997 HL patients (diagnosed 1973-2013; 45% ≥50 years).

RESULTS

The 1-year RSRs (95% confidence interval; CI) for males aged 45-59, 60-69, 70-80, and 81 years and over, diagnosed in 2013, were 0.95 (0.91-0.97), 0.88 (0.81-0.92), 0.74 (0.63-0.81), and 0.52 (0.35-0.67), respectively. The corresponding 1-year RSRs for females were 0.97 (0.94-0.98), 0.91 (0.85-0.95), 0.82 (0.73-0.88), and 0.66 (0.50-0.77). No improvements in 1-year of 5-year relative survival from 2000 to 2013 were observed for patients aged 45-59 or 60-69 but there were modest improvements for patients aged 70 years and older. Importantly, we saw no changes in the distribution of disease or patient characteristics between 2000 and 2013.

CONCLUSIONS

Elderly patients constitute a large group with clearly unmet medical needs. Our findings motivate a more active approach to including elderly patients in clinical trials. Our study provides a baseline for outcome comparison after the broader introduction of targeted drugs.

Adjusting Expected Mortality Rates Using Information From a Control Population: An Example Using Socioeconomic Status

Expected or reference mortality rates are commonly used in the calculation of measures such as relative survival in population-based cancer survival studies and standardized mortality ratios. These expected rates are usually presented according to age, sex, and calendar year. In certain situations, stratification of expected rates by other factors is required to avoid potential bias if interest lies in quantifying measures according to such factors as, for example, socioeconomic status. If data are not available on a population level, information from a control population could be used to adjust expected rates. We have presented two approaches for adjusting expected mortality rates using information from a control population: a Poisson generalized linear model and a flexible parametric survival model. We used a control group from BCBaSe-a register-based, matched breast cancer cohort in Sweden with diagnoses between 1992 and 2012-to illustrate the two methods using socioeconomic status as a risk factor of interest. Results showed that Poisson and flexible parametric survival approaches estimate similar adjusted mortality rates according to socioeconomic status. Additional uncertainty involved in the methods to estimate stratified, expected mortality rates described in this study can be accounted for using a parametric bootstrap, but this might make little difference if using a large control population.

Risk for Arterial and Venous Thrombosis in Patients With Myeloproliferative Neoplasms: A Population-Based Cohort Study

BACKGROUND

Patients with myeloproliferative neoplasms (MPNs) are reported to be at increased risk for thrombotic events. However, no population-based study has estimated this excess risk compared with matched control participants.

OBJECTIVE

To assess risk for arterial and venous thrombosis in patients with MPNs compared with matched control participants.

DESIGN

Matched cohort study.

SETTING

Population-based setting in Sweden from 1987 to 2009, with follow-up to 2010.

PATIENTS

9429 patients with MPNs and 35 820 matched control participants.

MEASUREMENTS

The primary outcomes were rates of arterial and venous thrombosis. Flexible parametric models were used to calculate hazard ratios (HRs) and cumulative incidence with 95% CIs.

RESULTS

The HRs for arterial thrombosis among patients with MPNs compared with control participants at 3 months, 1 year, and 5 years were 3.0 (95% CI, 2.7 to 3.4), 2.0 (CI, 1.8 to 2.2), and 1.5 (CI, 1.4 to 1.6), respectively. The corresponding HRs for venous thrombosis were 9.7 (CI, 7.8 to 12.0), 4.7 (CI, 4.0 to 5.4), and 3.2 (CI, 2.9 to 3.6). The rate was significantly elevated across all age groups and was similar among MPN subtypes. The 5-year cumulative incidence of thrombosis in patients with MPNs showed an initial rapid increase followed by gentler increases during follow-up. The HR for venous thrombosis decreased during more recent calendar periods.

LIMITATION

No information on individual laboratory results or treatment.

CONCLUSION

Patients with MPNs across all age groups have a significantly increased rate of arterial and venous thrombosis compared with matched control participants, with the highest rates at and shortly after diagnosis. Decreases in the rate of venous thrombosis over time likely reflect advances in clinical management.

PRIMARY FUNDING SOURCE

The Cancer Research Foundations of Radiumhemmet, Blodcancerfonden, the Swedish Research Council, the regional agreement on medical training and clinical research between Stockholm County Council and Karolinska Institutet, the Adolf H. Lundin Charitable Foundation, and Memorial Sloan Kettering Cancer Center.

Second malignancies in patients with myeloproliferative neoplasms: a population-based cohort study of 9379 patients

To determine the risk of a wide range of second malignancies in patients with myeloproliferative neoplasms (MPNs), we conducted a large population-based study and compared the results to matched controls. From national Swedish registers, 9379 patients with MPNs diagnosed between 1973 and 2009, and 35,682 matched controls were identified as well as information on second malignancies, with follow-up until 2010. Hazard ratios (HRs) with 95 % confidence intervals (CIs) were calculated using Cox regression and a flexible parametric model. There was a significantly increased risk of any non-hematologic cancer with HR of 1.6 (95% CI: 1.5-1.7). The HRs for non-melanoma skin cancer was 2.8 (2.4-3.3), kidney cancer 2.8 (2.0-4.0), brain cancer 2.8 (1.9-4.2), endocrine cancers 2.5 (1.6-3.8), malignant melanoma 1.9 (1.4-2.7), pancreas cancer 1.8 (1.2-2.6), lung cancer 1.7 (1.4-2.2), and head and neck cancer 1.7 (1.2-2.6). The HR of second malignancies was similar across all MPN subtypes, sex, and calendar periods of MPN diagnosis. The risk of developing a hematologic malignancy was also significantly increased; the HR for acute myeloid leukemia was 46.0 (32.6-64.9) and for lymphoma 2.6 (2.0-3.3). In conclusion, our study provides robust population-based support of an increased cancer risk in MPN patients.

Sex differences in cancer risk and survival: A Swedish cohort study

AIM

The aim of this study is to firmly delineate temporal and age trends regarding sex discrepancies in cancer risk and survival as well as quantifying the potential gain achieved by eliminating this inequality.

METHODS

We performed a population-based cohort study using data on all adult incident cancer cases (n = 872,397) recorded in the Swedish Cancer Register in 1970-2014. To assess the associations between sex and cancer risk and sex and survival, male-to-female incidence rate ratios (IRRs) and excess mortality ratios (EMRs) adjusted for age and year of diagnosis were estimated using Poisson regression.

RESULTS

Men were at increased risk for 34 of 39 and had poorer prognosis for 27 of 39 cancers. Women were at increased risk for 5 of 39 and had significantly poorer survival for 2 of 39 cancers. IRRs among male predominant sites ranged from 1.05; 95% confidence interval (CI), 1.03--1.1 (lung adenocarcinoma) to 8.0; 95% CI, 7.5-8.5 (larynx). EMRs among sites with male survival disadvantage ranged from 1.1; 95% CI, 1.03-1.1 (colon) to 2.1; 95% CI, 1.5--2.8 (well-differentiated thyroid).

CONCLUSION

Male sex is associated with increased risk and poorer survival for most cancer sites. Identifying and eliminating factors driving the observed sex differences may reduce the global cancer burden.

The underreporting of hepatocellular carcinoma to the cancer register and a log-linear model to estimate a more correct incidence

The Cancer Register (CR) in Sweden has reported that the incidence of primary liver cancer (PLC) has slowly declined over the last decades. Even though all cancers, irrespective of diagnostic method, should be reported to the CR, the PLC incidence may not reflect the true rate. Improved diagnostic tools have enabled diagnosis of hepatocellular carcinoma based on noninvasive methods without histological verification, possibly associated with missed cancer reports or misclassification in the CR. Our objective was to study the completeness and assess the underreporting of PLC to the CR and to produce a more accurate estimate based on three registers. The CR, the Cause of Death Register, and the Patient Register were investigated. Differences and overlap were examined, the incidence was estimated by merging data from the registers, and the number reported to none of the registers was estimated using a log-linear capture-recapture model. The results show that 98% of the PLCs reported to the CR were histologically verified; 80% were hepatocellular carcinoma and 20% were intrahepatic cholangiocarcinoma. Unspecified liver cancer decreased over time and constituted <10% of all reported liver cancers. The CR may underestimate the liver cancer incidence by 37%-45%, primarily due to missed cancer reports. The estimated annual number of liver cancers increased over time, but the standardized incidence was stable around 11 per 100,000. Hepatitis C-associated liver cancer increased and constituted 20% in 2010.

CONCLUSION

There was an underreporting of PLC diagnosed by noninvasive methods; the incidence was considerably higher than estimated by the CR, with a stable incidence over time; reporting needs to improve and combining registers is recommended when studying incidence. (Hepatology 2017;65:885-892).

Life Expectancy of Patients With Chronic Myeloid Leukemia Approaches the Life Expectancy of the General Population

PURPOSE

A dramatic improvement in the survival of patients with chronic myeloid leukemia (CML) occurred after the introduction of imatinib mesylate, the first tyrosine kinase inhibitor (TKI). We assessed how these changes affected the life expectancy of patients with CML and life-years lost as a result of CML between 1973 and 2013 in Sweden.

MATERIALS AND METHODS

Patients recorded as having CML in the Swedish Cancer Registry from 1973 to 2013 were included in the study and followed until death, censorship, or end of follow-up. The life expectancy and loss in expectation of life were predicted from a flexible parametric relative survival model.

RESULTS

A total of 2,662 patients with CML were diagnosed between 1973 and 2013. Vast improvements in the life expectancy of these patients were seen over the study period; larger improvements were seen in the youngest ages. The great improvements in life expectancy translated into great reductions in the loss in expectation of life. Patients of all ages diagnosed in 2013 will, on average, lose < 3 life-years as a result of CML.

CONCLUSION

Imatinib mesylate and new TKIs along with allogeneic stem cell transplantation and other factors have contributed to the life expectancy in patients with CML approaching that of the general population today. This will be an important message to convey to patients to understand the impact of a CML diagnosis on their life. In addition, the increasing prevalence of patients with CML will have a great effect on future health care costs as long as continuous TKI treatment is required.

Life Expectancy of Patients With Chronic Myeloid Leukemia Approaches the Life Expectancy of the General Population

PURPOSE

A dramatic improvement in the survival of patients with chronic myeloid leukemia (CML) occurred after the introduction of imatinib mesylate, the first tyrosine kinase inhibitor (TKI). We assessed how these changes affected the life expectancy of patients with CML and life-years lost as a result of CML between 1973 and 2013 in Sweden.

MATERIALS AND METHODS

Patients recorded as having CML in the Swedish Cancer Registry from 1973 to 2013 were included in the study and followed until death, censorship, or end of follow-up. The life expectancy and loss in expectation of life were predicted from a flexible parametric relative survival model.

RESULTS

A total of 2,662 patients with CML were diagnosed between 1973 and 2013. Vast improvements in the life expectancy of these patients were seen over the study period; larger improvements were seen in the youngest ages. The great improvements in life expectancy translated into great reductions in the loss in expectation of life. Patients of all ages diagnosed in 2013 will, on average, lose < 3 life-years as a result of CML.

CONCLUSION

Imatinib mesylate and new TKIs along with allogeneic stem cell transplantation and other factors have contributed to the life expectancy in patients with CML approaching that of the general population today. This will be an important message to convey to patients to understand the impact of a CML diagnosis on their life. In addition, the increasing prevalence of patients with CML will have a great effect on future health care costs as long as continuous TKI treatment is required.

Abstract P6-10-07: Family history and risk of pregnancy-associated breast cancer (PABC)

Background: The risk of breast cancer is at least doubled in young women with a family history of breast cancer. Pregnancy has a dual effect on breast cancer risk; a short-term increase followed by a long-term protection. It has been hypothesized that women with a genetic predisposition for breast cancer are particularly susceptible to physiological changes during childbearing that may influence short term risk.

Materials & methods: We followed a cohort of women aged 15 to 44 years between 1963 and 2009 identified in Swedish registers. Family history was defined as having a mother or sister with breast cancer. In a case-cohort analysis, we estimated incidence rate ratios of breast cancer during pregnancy and time intervals up to 10 years post-delivery.

Results: In 3,452,506 women, there were 15,548 cases of breast cancer (1,208 were pregnancy-associated (PABC), defined as breast cancer during or within 2 years of pregnancy). Compared to nulliparous women, the risk of breast cancer was decreased during pregnancy, similar during 1st year and increased during 2nd year post-delivery. The pattern was similar in women with or without family history of breast cancer. A peak in risk was observed 5-6 years following the first birth regardless of family history. After a second birth, this peak was only present in women with a family history.

Conclusions: Our results indicate that women with a family history of breast cancer do not have a different breast cancer risk during and within 10 years following pregnancy compared to women without a family history.

Citation Format: Lambe M, Johansson ALV, Andersson TM, Hsieh C-C, Cnattingius S, Dickman PW. Family history and risk of pregnancy-associated breast cancer (PABC). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-10-07.

Continued improvement in survival of acute myeloid leukemia patients: an application of the loss in expectation of life

We evaluated temporal trends in survival of Swedish acute myeloid leukemia (AML) patients diagnosed between 1973 and 2011 using relative survival ratios (RSRs) and a measure called the loss in expectation of life (LEL). RSRs increased most for patients <60 years at diagnosis during the first calendar periods, but between 1997-2005 and 2006-2011 the most pronounced increase was for those aged 61-70 years at diagnosis; RSR changed from 0.16 (95% confidence interval (CI): 0.13-0.19) to 0.28 (95% CI: 0.23-0.33), respectively. The LEL for males aged 35 years at diagnosis was 41.0 (95% CI: 40.1-41.8) years in 1975 and 19.5 (95% CI: 16.4-22.5) years in 2011. For males aged 65 years, the corresponding figures were 13.8 (95% CI: 13.7-14.0) and 12.0 (95% CI: 11.3-12.8). Conditional LEL estimates suggested that patients who survive 5 years postdiagnosis have shorter remaining lifespan than the general population. The proportion of expected life lost (PELL) suggested that male 65-year-old patients lost 75% of their life expectancy in 2005 and 66% if they were diagnosed in 2011. Survival continued to increase to 2011, with larger improvements in those aged 61-70 years at diagnosis. The LEL and PELL are intuitive measures that may be useful in communicating survival statistics to patients, clinicians and health-care providers.

Pregnancy and the Risk of Relapse in Patients Diagnosed With Hodgkin Lymphoma

PURPOSE

Many patients and clinicians are worried that pregnancy after the diagnosis of Hodgkin lymphoma (HL) may increase the risk of relapse despite a lack of empirical evidence to support such concerns. We investigated if an association exists between pregnancy and relapse in women with a diagnosis of HL.

MATERIALS AND METHODS

Using Swedish healthcare registers combined with medical records, we included 449 women who received a diagnosis of HL between 1992 and 2009 and who were age 18 to 40 years at diagnosis. Follow-up started 6 months after diagnosis, when the patients' condition was assumed to be in remission. Pregnancy-associated relapse was defined as a relapse during pregnancy or within 5 years after delivery. Hazard ratios (HRs) with 95% CIs were estimated by using the Cox proportional hazards model.

RESULTS

Among the 449 women, 144 (32%) became pregnant during follow-up. Overall, 47 relapses were recorded, of which one was a pregnancy-associated relapse. The adjusted HR for the comparison of the pregnancy-associated relapse rate to the non-pregnancy-associated relapse rate was 0.29 (95% CI, 0.04 to 2.18). The expected number of relapses in women with a recent pregnancy, given that they would experience the same relapse rate as that of women without a recent pregnancy, was 3.76; the observed-to-expected ratio was 0.27 (95% exact CI, 0.01 to 1.51).

CONCLUSION

We found no evidence that a pregnancy after diagnosis increases the relapse rate among women whose HL is in remission. Survivors of HL need to consider a range of factors when deciding about future reproduction. However, given the results of this study, the risk of pregnancy-associated relapse does not need to be considered.

Comparison of different approaches to estimating age standardized net survival

BACKGROUND

Age-standardized net survival provides an important population-based summary of cancer survival that appropriately accounts for differences in other-cause mortality rates and standardizes the population age distribution to allow fair comparisons. Recently, there has been debate over the most appropriate method for estimating this quantity, with the traditional Ederer II approach being shown to have potential bias.

METHODS

We compare lifetable-based estimates (Ederer II), a new unbiased method based on inverse probability of censoring weights (Pohar Perme) and model-based estimates. We make the comparison in a simulation setting; generating scenarios where we would expect to see a large theoretical bias.

RESULTS

Our simulations demonstrate that even in relatively extreme scenarios there is negligible bias in age-standardized net survival when using the age-standardized Ederer II method, modelling with continuous age or using the Pohar Perme method. However, both the Ederer II and modelling approaches have some advantages over the Pohar Perme method in terms of greater precision, particularly for longer-term follow-up (10 and 15 years).

CONCLUSIONS

Our results show that, when age-standardizing, concern over bias with the traditional methods is unfounded. We have also shown advantages in using the more traditional and modelling methods.

Risk and Cause of Death in Patients Diagnosed With Myeloproliferative Neoplasms in Sweden Between 1973 and 2005: A Population-Based Study

PURPOSE

Myeloproliferative neoplasms (MPNs) are associated with a shortened life expectancy. We assessed causes of death in patients with MPN and matched controls using both relative risks and absolute probabilities in the presence of competing risks.

PATIENTS AND METHODS

From Swedish registries, we identified 9,285 patients with MPN and 35,769 matched controls. A flexible parametric model was used to estimate cause-specific hazard ratios (HRs) of death and cumulative incidence functions, each with 95% CIs.

RESULTS

In patients with MPN, the HRs of death from hematologic malignancies and infections were 92.8 (95% CI, 70.0 to 123.1) and 2.7 (95% CI, 2.4 to 3.1), respectively. In patients age 70 to 79 years at diagnosis (the largest patient group), the HRs of death from cardiovascular and cerebrovascular disease were 1.5 (95% CI, 1.4 to 1.7) and 1.5 (95% CI, 1.3 to 1.8), respectively; all were statistically significantly elevated compared with those of controls. In the same age group, no difference was observed in the 10-year probability of death resulting from cardiovascular disease in patients with MPN versus controls (16.8% v 15.2%) or cerebrovascular disease (5.6% v 5.2%). In patients age 50 to 59 years at diagnosis, the 10-year probability of death resulting from cardiovascular and cerebrovascular disease was elevated, 4.2% versus 2.1% and 1.9% versus 0.4%, respectively. Survival in patients with MPN increased over time, mainly because of decreased probabilities of dying as a result of hematologic malignancies, infections, and, in young patients, cardiovascular disease.

CONCLUSION

Patients with MPN had an overall higher mortality rate than that of matched controls, primarily because of hematologic malignancy, infections, and vascular events in younger patients. Evidently, there is still a need for effective disease-modifying agents to improve patient outcomes.