A comparison of relative and cause-specific survival by cancer site, age and time since diagnosis

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.

Breast cancer incidence and survival in Scotland by socio-economic deprivation and tumour subtype

Background

Women from socio-economically deprived areas are less likely to develop and then to survive breast cancer (BC). Whether associations between deprivation and BC incidence and survival differ by tumour molecular subtypes and mode of detection in Scotland are unknown.

Methods

Data consisted of 62,378 women diagnosed with invasive BC between 2000 and 2016 in Scotland. Incidence rates and time trends were calculated for oestrogen receptor positive (ER+) and negative (ER−) tumours and stratified by the Scottish Index of Multiple Deprivation (SIMD) quintiles and screening status. SIMD is an area-based measure derived across seven domains: income, employment, education, health, access to services, crime and housing. We calculated adjusted hazard ratios (aHR [95% confidence intervals]) for BC death by immunohistochemical surrogates of molecular subtypes for the most versus the least deprived quintile. We adjusted for mode of detection and other confounders.

Results

In Scotland, screen-detected ER+tumour incidence increased over time, particularly in the least deprived quintile [Average Annual Percentage Change (AAPC) = 2.9% with 95% CI from 1.2 to 4.7]. No marked differences were observed for non-screen-detected ER+tumours or ER− tumours by deprivation. BC mortality was higher in the most compared to the least deprived quintile irrespective of ER status (aHR = 1.29 [1.18, 1.41] for ER+ and 1.27 [1.09, 1.47] for ER− tumours). However, deprivation was associated with significantly higher mortality for luminal A and HER2−enriched tumours (aHR = 1.46 [1.13, 1.88] and 2.10 [1.23, 3.59] respectively) but weaker associations for luminal B and TNBC tumours that were not statistically significant.

Conclusions

Deprivation is associated with differential BC incidence trends for screen-detected ER+tumours and with higher mortality for select tumour subtypes. Future efforts should evaluate factors that might be associated with reduced survival in deprived populations and monitor progress stratified by tumour subtypes and mode of detection.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-022-06632-1.

Inverse probability weighting and doubly robust standardization in the relative survival framework

A commonly reported measure when interested in the survival of cancer patients is relative survival. Relative survival circumvents issues with inaccurate cause of death information by incorporating the expected mortality rates of cancer individuals from population lifetables of the general population. A summary of the cancer population prognosis can be obtained using the marginal relative survival. To explore differences between exposure groups, such as socioeconomic groups, the difference in marginal relative survival between exposed and unexposed can be obtained and under assumptions is interpreted as the average causal effect of exposure to survival. In a modeling context, this is usually estimated by applying regression standardization as the average of the individual-specific estimates after fitting a relative survival model. Regression standardization yields an estimator that consistently estimates the causal effect under standard causal inference assumptions and if the relative survival model is correctly specified. We extend inverse probability weighting (IPW) and doubly robust standardization methods in the relative survival framework as additional valuable tools for obtaining average causal effects when correct model specification might not hold for the relative survival model. IPW yields an unbiased estimate of the average causal effect if a correctly specified model has been fitted for the exposure (propensity score) whereas doubly robust standardization requires that at least one of the propensity score model or the relative survival model is correctly specified. An example using data on melanoma is provided and a simulation study is conducted to investigate how sensitive are the methods to model misspecification, including different ways for obtaining standard errors.

Prostate Cancer Survival by Risk and Other Prognostic Factors in Mallorca, Spain

Studies about the survival of patients with prostate cancer by stage or risk of progression are scarce. The aims of this study were (1) to determine the cause-specific survival by risk in prostate cancer patients in Mallorca diagnosed in the period 2006-2011; (2) to identify the factors that explain and predict the likelihood of survival and the risk of dying from this type of cancer; and (3) to determine the distribution of prostate cancer by risk in the patients in Mallorca diagnosed in the period 2006-2011. Incident prostate cancer cases diagnosed between 2006 and 2011 were identified through the Mallorca Cancer Registry. We collected age; date and method of diagnosis; date of follow-up or death; T, N, M and stage according to the TNM 7th edition; Gleason score; prostate-specific antigen (PSA); histology according to the International Classification of Diseases for Oncology (ICD-O) 3rd edition, comorbidities and treatments. We calculated risk in four categories: low, medium, high and very high. The end point of follow-up was 31 December 2014. Multiple imputation (MI) was performed to estimate cases with unknown risk. We identified 2921 cases. Five years after diagnosis, survival after MI was 89% globally, and was 100% for low-risk cases, 96% for medium risk, 93% for high risk and 69% for very-high-risk cases. Cases with histology other than adenocarcinoma, with high (and especially very high) risk, as well as with systemic, mixed and observation/unspecified treatments had worse prognoses.

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.

Mortality from cardiovascular disease in women with breast cancer - a nationwide registry study

BACKGROUND

Only few existing studies have investigated the mortality from cardiovascular disease (CVD) in women with breast cancer (BC). The aim of this study was to investigate CVD mortality in patients with BC compared with a matched control group without BC using national registry data.

MATERIAL AND METHODS

We followed 16,505 Danish women diagnosed with BC in 2003-2007 up to 10 years after BC diagnosis compared with 165,042 matched controls from the general Danish population. The matching criteria included gender, age, region of residence, and education. We performed multivariate Cox regression analyses to investigate the influence of preexisting CVD on mortality. Moreover, we used the cumulative incidence and conditional probability functions to study the risk of CVD-related death in the presence of competing risk, i.e., the risk of dying from other causes than CVD.

RESULTS

We found that preexisting CVD increased both overall mortality and CVD mortality in both patients with BC and controls. Furthermore, we found that patients with BC were at lower risk of dying from CVD up to 10 years after BC diagnosis compared with controls. The cumulative incidence of CVD as underlying cause of death was 4.0% in patients with BC and 5.7% in controls after 10 years. The most common CVD-related causes of death were ischemic heart disease including acute coronary syndrome, cerebrovascular accident, heart failure, and atrial fibrillation.

DISCUSSION

Our study contributes to the growing body of work on BC and comorbidities and highlights the importance of CVD in individuals with BC. Further studies are needed to confirm our finding that patients with BC are at lower risk of dying from CVD up to 10 years after BC diagnosis compared with a matched control group without BC.

Impact of COVID-19 on healthcare organisation and cancer outcomes

BACKGROUND

Changes in the management of patients with cancer and delays in treatment delivery during the COVID-19 pandemic may impact the use of hospital resources and cancer mortality.

PATIENTS AND METHODS

Patient flows, patient pathways and use of hospital resources during the pandemic were simulated using a discrete event simulation model and patient-level data from a large French comprehensive cancer centre's discharge database, considering two scenarios of delays: massive return of patients from November 2020 (early-return) or March 2021 (late-return). Expected additional cancer deaths at 5 years and mortality rate were estimated using individual hazard ratios based on literature.

RESULTS

The number of patients requiring hospital care during the simulation period was 13,000. In both scenarios, 6-8% of patients were estimated to present a delay of >2 months. The overall additional cancer deaths at 5 years were estimated at 88 in early-return and 145 in late-return scenario, with increased additional deaths estimated for sarcomas, gynaecological, liver, head and neck, breast cancer and acute leukaemia. This represents a relative additional cancer mortality rate at 5 years of 4.4 and 6.8% for patients expected in year 2020, 0.5 and 1.3% in 2021 and 0.5 and 0.5% in 2022 for each scenario, respectively.

CONCLUSIONS

Pandemic-related diagnostic and treatment delays in patients with cancer are expected to impact patient survival. In the perspective of recurrent pandemics or alternative events requiring an intensive use of limited hospital resources, patients should be informed not to postpone care, and medical resources for patients with cancer should be sanctuarised.

Cause of death for patients with breast cancer: discordance between death certificates and medical files, and impact on survival estimates

BACKGROUND

Registration and coding of cause of death is prone to error since determining the exact underlying condition leading directly to death is challenging. In this study, causes of death from the death certificates were compared to patients' medical files interpreted by experts at University Hospitals Leuven (UHL), to assess concordance between sources and its impact on cancer survival assessment.

METHODS

Breast cancer patients treated at UHL (2009-2014) (follow-up until December 31st 2016) were included in this study. Cause of death was obtained from death certificates and expert-reviewed medical files at UHL. Agreement was calculated using Cohen's kappa coefficient. Cause-specific survival (CSS) was calculated using the Kaplan-Meier method and the relative survival probability (RS) using the Ederer II and Pohar Perme method.

RESULTS

A total of 2862 patients, of whom 354 died, were included. We found an agreement of 84.7% (kappa-value of 0.69 (95% C.I.: 0.62-0.77)) between death certificates and medical files. Death certificates had 10.7% false positive and 4.5% false negative rates. However, five-year CSS and RS measures were comparable for both sources.

CONCLUSION

For breast cancer patients included in our study, fair agreement of cause of death was seen between death certificates and medical files with similar CSS and RS estimations.

Cancer-specific survival by stage of bladder cancer and factors collected by Mallorca Cancer Registry associated to survival

Background

Information about survival by stage in bladder cancer is scarce, as well as about survival of non-invasive bladder cancer. The aims of this study are: 1) to find out the distribution of bladder cancer by stage; 2) to determine cancer-specific survival by stage of bladder cancer; 3) to identify factors that explain and predict the likelihood of survival and the risk of dying from these cancers.

Methods

Incident bladder cancer cases diagnosed between 2006 and 2011 were identified through the Mallorca Cancer Registry. Inclusion criteria: cases with code C67 according to the ICD-O 3rd edition with any behaviour and any histology, except lymphomas and small cell carcinomas. Cases identified exclusively through the death certificate were excluded. We collected the following data: sex; age; date and method of diagnosis; histology according to the ICD-O 3rd edition; T, N, M and stage at the time of diagnosis; and date of follow-up or death. End point of follow-up was 31 December 2015. Multiple imputation (MI) was performed to estimate cases with unknown stage. Cases with benign or indeterminate behaviour were excluded for the survival analysis. Actuarial and Kaplan-Meier methods and Cox regression models were used for survival analysis.

Results

One thousand nine hundred fourteen cases were identified. 14% were women and 65.4% were 65 years or older. 3.9% had no stage (benign or undetermined behaviour) and 11.5% had unknown stage. After MI, 37.5% were in stage Ta (non-invasive papillary carcinoma), 3.2% in stage Tis (carcinoma in situ), 34.3% in stage I, 11.7% in Stage II, 4.3% in stage III, and 9.0% in stage IV. Survival was 76% at 5 years. Survival by stage: 98% at stage Ta, 90% at stage Tis, 85% at stage I, 45% at stage II, 35% at stage III, and 7% at stage IV. The Cox model showed that age, histology, and stage, but not sex, were associated with survival.

Conclusion

Bladder cancer survival vary greatly with stage, among both non-invasive and invasive cases. The percentage of non-invasive cancers is high. Stage, age, and histology are associated to survival.

Clinical characteristics and outcomes among 2347 patients aged ≥85 years with major lymphoma subtypes: a Nordic Lymphoma Group study

There is a lack of data regarding treatment and prognosis for the growing group of oldest old patients with lymphoma. Therefore, we studied 2347 patients aged ≥85 years from the Danish and Swedish lymphoma registers 2000–2016 (Denmark) and 2007–2013 (Sweden). Outcome was assessed using relative survival (RS). The 2‐year RS overall for patients with aggressive lymphomas was 38% [95% confidence interval (CI) 35–42%], of whom 845 (66%) patients received active treatment (chemotherapy, radiotherapy, immunotherapy, other). For aggressive lymphomas, not receiving active treatment was associated with an inferior 2‐year RS of 12% (95% CI 9–17%) compared to 49% (95% CI 45–53%) for patients who received active treatment (excess mortality rate ratio 2·84, 95% CI 2·3–3·5; P < 0·0001). For patients with indolent lymphoma, the 2‐year RS was 77% (95% CI 72–82%). Here, 383 (46%) patients received active treatment at diagnosis, but did not have better 2‐year RS (75%, 95% CI 67–81%) compared to those who did not receive active treatment (83%, 95% CI 74–89%). We conclude that outcomes for the oldest old patients with lymphoma are encouraging for several subtypes and that active treatment is associated with improved outcome amongst the oldest old patients with aggressive lymphomas, indicating that age itself should not be a contraindication to treatment.

Increased curative treatment is associated with decreased prostate cancer-specific and overall mortality in senior adults with high-risk prostate cancer; results from a national registry-based cohort study

Background

The association between curative treatment (CurTrt) and mortality in senior adults (≥70 years) with high‐risk prostate cancer (PCa) is poorly documented. In a population‐based cohort we report temporal trends in treatment and PCa‐specific mortality (PCSM), investigating the association between CurTrt and mortality in senior adults with high‐risk PCa, compared to findings in younger men (<70 years).

Methods

Observational study from the Cancer Registry of Norway. Patients with high‐risk PCa were stratified for three diagnostic periods (2005‐08, 2009‐12 and 2013‐16), age (<70, vs ≥70) and primary treatment (CurTrt: Radical prostatectomy (RP), Radiotherapy (RAD) vs no curative treatment (NoCurTrt)). Competing risk and Kaplan‐Meier methods estimated PCSM and overall mortality (OM), respectively. Multivariable logistic regression models estimated odds for CurTrt, and multivariable Fine Gray and Cox regression models evaluated the hazard ratios for PCSM and OM.

Results

Of 19 763 evaluable patients, 54% were aged ≥70 years. Senior adults had more unfavorable PCa characteristics than younger men. Across diagnostic periods, use of CurTrt increased from 15% to 51% in men aged ≥70 and 65% to 81% in men aged < 70 years. With median five years follow‐up, PCSM decreased in all patients (P < .05), in the third period restricted to senior adults. In all patients NoCurTrt was associated with three‐fold higher 5‐year PCSM and two‐fold higher OM compared to CurTrt.

Conclusions

In high‐risk PCa patients, increased use of CurTrt, greatest in senior men, was observed along with decreased PCSM and OM in both senior and younger adults. CurTrt should increasingly be considered in men ≥70 years.

Oncological outcomes of radical nephroureterectomy for upper urinary tract urothelial neoplasia in Denmark

Objective: To report the oncological outcomes of radical nephroureterectomy for upper urinary tract urothelial neoplasia in a large study sample.Materials and methods: This was a nationwide multicenter registry-based cohort study of all patients with upper urinary tract urothelial neoplasia in Denmark found to be eligible for nephroureterectomy between April 2004 and April 2017 (N = 1384). Primary endpoints were intravesical recurrence-free survival and overall survival. Survival probabilities were estimated with Kaplan-Meier and the log-rank test to compare survival curves. Association with clinical outcomes was studied using univariate and multivariate Cox proportional hazards.Results: Intravesical recurrence-free survival was 72% [95% confidence interval (CI) 69-75%] at 5 years and 70% (95% CI 67-73%) at 10 years. Patients with muscle-invasive disease had a significantly lower rate of intravesical recurrence [hazard ratio (HR) = 0.46, p < 0.0001] and patients with high-grade tumors had a significantly higher rate of incident intravesical recurrence compared to low-grade tumors (HR = 1.65, p = 0.001). The overall survival was 76% (95% CI 74-79%) at 5 years and 64% (95% CI 60-70%) at 10 years. Patients with higher age (p = 0.008) and muscle-invasive disease (p < 0.0001) had worse overall survival. When comparing surgical approaches, laparoscopic nephroureterectomy versus open nephroureterectomy did not differ in intravesical recurrence-free survival but was associated with shorter postoperative hospital stay (p < 0.0001) and better overall survival (p = 0.02).Conclusions: We report the oncological outcomes of radical nephroureterectomy for upper urinary tract urothelial neoplasia in a large sample and give insights into predictive factors with significant impact.

The Eighth Edition of the American Joint Committee on Cancer Distant Metastases Stage Classification for Metastatic Pancreatic Neuroendocrine Tumors Might Be Feasible for Metastatic Pancreatic Ductal Adenocarcinomas

BACKGROUND

Significant modifications have been made to the 8th edition of the American Joint Committee on Cancer (AJCC) distant metastases (M) stage classification for metastatic pancreatic neuroendocrine tumors (PanNETs). We aimed to validate this revised classification among metastatic PanNET patients using the Surveillance, Epidemiology, and End Results database. We further sought to evaluate the feasibility of applying this classification to metastatic pancreatic neuroendocrine carcinoma (PanNEC) and pancreatic ductal adenocarcinoma (PDAC) patients.

METHODS

Stage IV pancreatic neuroendocrine neoplasm (PanNEN, including G1/G2 PanNET and G3 PanNEC classified according to the World Health Organization [WHO] 2010 grading scheme) and PDAC patients with metastatic disease diagnosed between 2010 and 2015 were identified and restaged according to the revised M stage classification for PanNET. Overall survival (OS) was compared using Kaplan-Meier analysis and log-rank test. Uni- and multivariate Cox regression models were utilized to identify prognostic factors.

RESULTS

A total of 1,371 stage IV PanNEN and 634 PDAC patients were included. Among PanNEN patients, liver (75.0%) was the most common metastatic site, followed by distant lymph nodes (8.5%), lung (8.4%), bone (7.3%), and brain (1.0%). The 5-year OS for PanNET patients with M1a, M1b, and M1c stage was 44.15, 53.32, and 19.70%, respectively. However, survival comparison showed no significant difference between M1a and M1b stages among PanNET patients. Similar findings were noted after applying this classification to PanNEC patients. Multivariate analysis showed that the age at diagnosis and the number of distant metastatic sites were independent prognostic factors for metastatic PanNEN patients. Interestingly, excellent survival discrimination by M stage among stage IV PDAC patients was noted (M1a vs. M1b vs. M1c, 5-year OS: 5.42, 2.46, and 0%, respectively).

CONCLUSION

Our study is the first large sample-based validation of the AJCC 8th M stage classification for PanNET. The revised classification did not effectively stratify metastatic PanNEN patients. However, further study is warranted to validate this classification for PanNET patients according to the WHO 2017 classification. Interestingly, the revised M stage classification might be feasible for PDAC patients with metastatic disease.

Differences in Cancer Survival with Relative versus Cause-Specific Approaches: An Update Using More Accurate Life Tables

BACKGROUND

We investigated differences in net cancer survival (survival observed if the only possible cause of death was the cancer under study) estimated using new approaches for relative survival (RS) and cause-specific survival (CSS).

METHODS

We used SEER data for patients diagnosed in 2000 to 2013, followed-up through December 31, 2014. For RS, we used new life tables accounting for geography and socio-economic status. For CSS, we used the SEER cause of death algorithm for attributing cancer-specific death. Estimates were compared by site, age, stage, race, and time since diagnosis.

RESULTS

Differences between 5-year RS and CSS were generally small. RS was always higher in screen-detectable cancers, for example, female breast (89.2% vs. 87.8%) and prostate (98.5% vs. 93.7%) cancers; differences increased with age or time since diagnosis. CSS was usually higher in the remaining cancer sites, particularly those related to specific risk factors, for example, cervix (70.9% vs. 68.3%) and liver (20.7% vs. 17.1%) cancers. For most cancer sites, the gap between estimates was smaller with more advanced stage.Conclusion: RS is the preferred approach to report cancer survival from registry data because cause of death may be inaccurate, particularly for older patients and long-term survivors as comorbidities increase challenges in determining cause of death. However, CSS proved to be more reliable in patients diagnosed with localized disease or cancers related to specific risk factors as general population life tables may not capture other causes of mortality.

IMPACT

Different approaches for net survival estimation should be considered depending on cancer under study.

Correcting for misclassification and selection effects in estimating net survival in clinical trials

BACKGROUND

Net survival, a measure of the survival where the patients would only die from the cancer under study, may be compared between treatment groups using either "cause-specific methods", when the causes of death are known and accurate, or "population-based methods", when the causes are missing or inaccurate. The latter methods rely on the assumption that mortality due to other causes than cancer is the same as the expected mortality in the general population with same demographic characteristics derived from population life tables. This assumption may not hold in clinical trials where patients are likely to be quite different from the general population due to some criteria for patient selection.

METHODS

In this work, we propose and assess the performance of a new flexible population-based model to estimate long-term net survival in clinical trials and that allows for cause-of-death misclassification and for effects of selection. Comparisons were made with cause-specific and other population-based methods in a simulation study and in an application to prostate cancer clinical trial data.

RESULTS

In estimating net survival, cause-specific methods seemed to introduce important biases associated with the degree of misclassification of cancer deaths. The usual population-based method provides also biased estimates, depending on the strength of the selection effect. Compared to these methods, the new model was able to provide more accurate estimates of net survival in long-term clinical trials.

CONCLUSION

Finally, the new model paves the way for new methodological developments in the field of net survival methods in multicenter clinical trials.

Nomograms for predicting survival outcomes in patients with primary tracheal tumors: a large population-based analysis

Background

The aim of this study was to develop and validate reliable nomograms to predict individual overall survival (OS) and cancer-specific survival (CSS) for patients with primary tracheal tumors and further estimate the role of postoperative radiotherapy (PORT) for these entities.

Patients and methods

A total of 405 eligible patients diagnosed between 1988 and 2015 were selected from the Surveillance, Epidemiology, and End Results database. All of them were randomly divided into training (n=303) and validation (n=102) sets. For the purpose of establishing nomograms, the Akaike information criterion was employed to select significant prognostic factors in multivariate Cox regression models. Both internal and external validations of the nomograms were evaluated by Harrell’s concordance index (C-index) and calibration plots. Propensity score matching (PSM) method was performed to reduce the influence of selection bias between the PORT group and the non-PORT group.

Results

Two nomograms shared common variables including age at diagnosis, histology, N and M stages, tumor size, and treatment types, while gender was only incorporated in the CSS nomogram. The C-indices of OS and CSS nomograms were 0.817 and 0.813, displaying considerable predictive accuracy. The calibration curves indicated consistency between the nomograms and the actual observations. When the nomograms were applied to the validation set, the results remained reconcilable. Moreover, the nomograms showed superiority over the Bhattacharyya’s staging system with regard to the C-indices. After PSM, PORT was not associated with significantly better OS or CSS. Only squamous cell carcinoma (SCC) patients in the PORT group had improved OS compared to non-PORT group.

Conclusion

The first two nomograms for predicting survival in patients with primary tracheal tumors were proposed in the present study. PORT seems to improve the prognosis of SCC patients, which needs further exploration.

Is time from diagnosis to radical prostatectomy associated with oncological outcomes?

PURPOSE

To study the association between time from diagnosis to radical prostatectomy (RP-interval) and prostate cancer-specific mortality (PCSM), histological findings in the RP-specimen and failure after RP (RP-failure).

METHODS

Patients diagnosed with non-metastatic prostate cancer (PCa) in 2001-2010 and prostatectomized within 180 days of biopsy were identified in the Cancer Registry of Norway and the Norwegian Prostate Cancer Registry. Patients were stratified according to risk groups and RP-intervals of 0-60, 61-90, 91-120 and 121-180 days. Aalen-Johansen and Kaplan-Meier methods estimated curves for PCSM, RP-failure and overall mortality. Multivariable Cox regressions and Chi-square tests were used to evaluate the impact of RP-interval on outcomes.

RESULTS

In 5163 eligible patients, the median time from diagnosis to RP was 93 days (range 1-180). Risk group distribution was similar in all RP-interval groups. With almost eight years of observation, no association was found between RP-interval and PCSM in the intermediate-or high-risk groups. Increasing RP-interval did not increase the rate of adverse histological outcomes or incidence of RP-failure.

CONCLUSIONS

Increasing RP-interval up to 180 days was not associated with adverse oncological outcomes at eight years follow-up. These findings should be considered when planning for prostatectomy.

Factors influencing access to palliative radiotherapy: a Norwegian population-based study

BACKGROUND

Palliative radiotherapy (PRT) comprises half of all radiotherapy use and is an effective and important treatment modality for improving quality of life in incurable cancer patients. We have described the use of PRT in Norway and aimed to identify and quantify the impact of factors associated with PRT utilization.

MATERIAL AND METHODS

Population-based data from the Cancer Registry of Norway identified 25,281 patients who died of cancer, 1 July 2009-31 December 2011. Additionally, individual-level data on socioeconomic status and community-level data on travel distance were collected. The proportion of patients who received PRT in the last two years of life (PRT_2Y) was calculated, and multivariable logistic regression was used to determine factors that influenced the PRT_2Y. Analyses of geographic variation in PRT use were also performed for the time period 2012-2016.

RESULTS

PRT_2Y for all cancer sites combined was 29.6% with wide geographic variations (standardized inter-county range; 21.8-36.6%). Female gender, increasing age at death, certain cancer sites, short survival time, and previous receipt of curative radiotherapy were associated with decreased odds of receiving PRT. Patients with low education, those living in certain counties, or with travel distances 100-499 km, were also less likely to receive PRT. Patients with low household income (adjusted odds ratio (OR) = 0.63; 95% confidence interval (CI) = 0.56-0.72) and those diagnosed in hospitals without radiotherapy facility (OR = 0.70; 95% CI = 0.64-0.77) had especially low likelihood of receiving PRT. Significant inter-county variation in use of PRT remained during the time period 2012-2016.

CONCLUSIONS

Despite a publicly funded, universal healthcare system with equity as a stated health policy aim, utilization of PRT in Norway is significantly associated with factors such as household income and availability of radiotherapy facility at the diagnosing hospital. Even after adjustments for relevant factors, unexplained geographic variations in PRT utilization exist.

A comparison of relative survival and cause-specific survival methods to measure net survival in cancer populations

Background

Accurate cancer survival statistics are necessary for describing population‐level survival patterns and measuring advancements in cancer care. Net cancer survival is measured using two methods: cause‐specific survival (CSS) and relative survival (RS). Both are valid methodologies for estimating net survival and are used widely in medical research. In these analyses, we compare CSS to RS at selected cancer sites.

Methods

Using data from 18 SEER registries between 2000 and 2014, five‐year RS and CSS estimates were generated overall as well as by age groups and by sex. To assess how closely the two survival methods corresponded, net survival percent difference was calculated with the following formula: ((RS‐CSS)/RS)*100.

Results

Discrepancies between estimates obtained from CSS and RS methods varied with cancer site and age, but not by sex. In most cases, CSS was greater than RS, but cancers with available early screening and high survival rate had higher RS than CSS. Net survival percent differences were small in children and adolescents and young adults, and large in adults over the age of 40.

Conclusions

While both CSS and RS aim to quantify net survival, the estimates tend to differ due to the biases present in both methodologies. Error when estimating CSS most frequently stems from misclassification of cause of death, whereas RS is subject to error when no suitable life tables are available. Appropriate use of CSS and RS requires a detailed understanding of the characteristics of the disease that may lead to differences in the estimates generated by these methods.

Geographical, racial and socio-economic variation in life expectancy in the US and their impact on cancer relative survival

PURPOSE

Despite gains in life expectancy between 1992 to 2012, large disparities in life expectancy continue to exist in the United States between subgroups of the population. This study aimed to develop detailed life tables (LT), accounting for mortality differences by race, geography, and socio-economic status (SES), to more accurately measure relative cancer survival and life expectancy patterns in the United States.

METHODS

We estimated an extensive set of County SES-LT by fitting Poisson regression models to deaths and population counts for U.S. counties by age, year, gender, race, ethnicity and county-level SES index. We reported life expectancy patterns and evaluated the impact of the County SES-LT on relative survival using data from the Surveillance Epidemiology and End Results (SEER) Program cancer registries.

RESULTS

Between 1992 and 2012, the largest increase in life expectancy was among black men (6.8 years), however there were still large geographical differences. Life expectancy was highest for Asian or Pacific Islanders (API), and lowest for American Indians and Alaskan Natives (AIAN). In 2010, life expectancies by state ranged from 73 to 82 years for white males, 78 to 86 years for white females, 66 to 75 for black males, and 75 to 81 for black females. Comparisons of relative survival using National LT and the new County SES-LT showed that relative survival using County SES-LT improved relative survival estimates for some demographic groups, particularly in low and high SES areas, among Hispanics and AIAN, and among older male cancer patients. Relative survival using County SES-LT was 7.3% and 6.7% survival points closer to cause-specific survival compared to the National LT relative survival for AIAN and Hispanic cancer patients diagnosed between ages 75 and 84 years, respectively. Importantly, the County SES-LT relative survival estimates were higher in lower SES areas and lower in higher SES areas, reducing differences in relative survival comparisons.

CONCLUSION

The use of these new socio-economic life tables (County SES-LT) can provide more accurate estimates of relative survival, improve comparisons of relative survival among registries, better illustrate disparities and cancer control efforts, and should be used as default for cancer relative survival using U.S. data.

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.

Critical Points for Interpreting Patients' Survival Rate Using Cancer Registries: A Literature Review

Background

Survival rate is used to develop cancer control plans. However, there are limitations and biases when interpreting patient survival rate data. This study aimed to identify and account for potential biases and/or limitations on estimating survival rate to enable more effective control of cancer.

Methods

The authors searched PubMed from December 2010 to December 2015 for articles that investigated or described biases in estimating patient survival using cancer registries. Articles that only described the tendency of survival rate and investigated relationships between patient characteristics, treatment, and survival rate were excluded.

Results

In total, 50 articles met the inclusion criteria. The identified potential biases were categorized into three areas, as follows: 1) the quality of registry data (eg, the completeness of cancer patients, accuracy of data, and follow-up rates); 2) limitations related to estimated methods of survival rates (eg, misclassification of cause of death for cause-specific survival rate or a lack of comparability of background mortality for relative survival rate); and 3) the comparability of survival rates among different groups (eg, age-adjustment or patients with multiple cancers).

Conclusion

We concluded that survival rate can be suitable for answering questions related to health policy and research. Several factors should be considered when interpreting survival rates estimated using cancer registries.

Ten-year Mortality in Men With Nonmetastatic Prostate Cancer in Norway

OBJECTIVE

To provide population-based data on 10-year prostate cancer-specific mortality (PCSM), overall mortality (OM), treatment, and prognostic factors in patients with nonmetastatic prostate cancer (PCa).

MATERIALS AND METHODS

Based on data from the Norwegian Prostate Cancer Registry, we calculated 10-year PCSM and OM in 3449 patients diagnosed with nonmetastatic PCa in 2004-2005 who underwent radical prostatectomy (n = 913), radiotherapy (n = 1334), or no local treatment (n = 1202). Patients were stratified according to risk group, Gleason grade group (GGG), and Eastern Cooperative Oncology Group (ECOG) performance status. Aalen-Johansen and Kaplan-Meier estimates and proportional hazards regressions were used.

RESULTS

The 10-year PCSM rate was 8.5% (radical prostatectomy: 1.5, radiotherapy: 6.2%, no local treatment: 16.3%) and the OM rate was 25.5%. In the low-risk group, the risk of dying from other causes was 8-fold increased compared with death from PCa, the comparable factor being approximately 2 among high-risk patients. Patients with high-risk factors seemed to benefit the most from local treatment. Within each risk group, the 5 GGGs improved the prediction of PCSM. Having an ECOG performance status of ≥1 doubled the risk of PCSM compared with patients with an ECOG performance status of 0.

CONCLUSION

For all patients, the 10-year OM was about 3 times higher than PCSM, the greatest and lowest discrepancies emerging among patients with low- and high-risk tumors, respectively. The results support increased use of local treatment in high-risk patients. GGGs should be implemented in clinical practice. The role of ECOG performance status as prognostic factor has to be validated in future studies.

Choice of relative or cause-specific approach to cancer survival analysis impacts estimates differentially by cancer type, population, and application: evidence from a Canadian population-based cohort study

Background

Cause-specific (CS) and net survival in a relative survival framework (RS) are two of the most common methods for estimating cancer survival. In this paper, we assess the differences in results produced by two permutations of cause-specific and relative survival applied to estimating cancer survival and disparities in cancer survival, using data from First Nations and non-Aboriginal populations in Canada.

Methods

Subjects were members of the 1991 Canadian Census Mortality Cohort, a population-based cohort of adult respondents to the 1991 Long Form Census who have been followed up for incident cancers and death through linkage to administrative databases. We compared four methods: relative survival analyses with ethnicity-specific life tables (RS-ELT); relative survival with general population life tables (RS-GLT); cause-specific survival with a broad definition of cancer death (CS-Broad); and cause-specific survival with a narrow definition of cause of death (CS-Narrow) and applied these to the nine most common cancers among First Nations.

Results

Apart from breast and prostate cancers, RS-ELT, RS-GLT, and CS-Broad tended to produce similar estimates of age-standardized five-year survival, whereas CS-Narrow yielded higher estimates of survival. CS-Narrow estimates were particularly unlike those based on the other methods for cancers of the digestive and respiratory tracts. Estimates of disparities in survival were generally comparable across the four methods except for breast and prostate cancers.

Conclusions

Cancer surveillance efforts in sub-populations defined by race, ethnicity, geography, socioeconomic status, or similar factors are necessary for identifying disparities and monitoring progress toward reducing them. In the absence of routine monitoring of cancer survival and cancer survival disparities in these populations, estimates generated by different methods will inevitably be compared over time and across populations. In this study, we demonstrate that caution should be exercised in making these comparisons, particularly in interpreting cause-specific survival rates with an unknown or narrow definition of cancer death and in estimates of breast and prostate cancer survival and/or disparities in survival generated by different methods.

Electronic supplementary material

The online version of this article (doi:10.1186/s12963-017-0142-4) contains supplementary material, which is available to authorized users.

Estimation of net survival for cancer patients: Relative survival setting more robust to some assumption violations than cause-specific setting, a sensitivity analysis on empirical data

Net survival is the survival that would be observed if the only possible underlying cause of death was the disease under study. It can be estimated with either cause-specific or relative survival data settings, if the informative censoring is properly considered. However, net survival estimators are prone to specific biases related to the data setting itself. We examined which data setting was the most robust against violation of key assumptions (erroneous cause of death and inappropriate life tables). We identified 4285 women in the Geneva Cancer Registry, diagnosed with breast, colorectal, lung cancer and melanoma between 1981 and 1991 and estimated net survival up to 20 years using cause-specific and relative survival settings. We used weights to tackle informative censoring in both settings and performed sensitivity analyses to evaluate the impact of misclassification of cause of death in the cause-specific setting or of using inappropriate life tables on net survival estimates in the relative survival setting. For all the four cancers, net survival was highest when using the cause-specific setting and the absolute difference between the two estimators increased with time since diagnosis. The sensitivity analysis showed that (i) the use of different life tables did not compromise net survival estimation in the relative survival setting, whereas (ii) a small level of misclassification for the cause of death led to a large change in the net survival estimate in the cause-specific setting. The relative survival setting was more robust to the above assumptions violations and is therefore recommended for estimation of net survival.

Multimodal therapy is feasible in elderly anal cancer patients

BACKGROUND

Many patients are diagnosed with an anal cancer in high ages. We here present the outcome after oncological therapy for patients above 80 years compared with younger patients.

MATERIALS AND METHODS

A series of 213 consecutive patients was diagnosed and treated at a single institution from 1984 to 2009. The patients received similar radiation doses but with different techniques, thus progressively sparing more normal tissues. The majority of patients also had simultaneous [5-fluorouracil (5FU) and mitomycin C] or induction chemotherapy (cisplatin and 5FU). The patients were stratified by age above or below 80 years. Despite that the goal was to offer standard chemoradiation treatment to all, the octo- and nonagenarians could not always be given chemotherapy.

RESULTS

In our series 35 of 213 anal cancer patients were above 80 years. After initial therapy similar complete response was observed, 80% above and 87% below 80 years. Local recurrence rate was also similar in both groups, 21% versus 26% (p = .187). Cancer-specific survival and relative survival were significantly lower in patients above 80 years, 60% and 50% versus 83% and 80%, (p = .015 and p = .027), respectively.

CONCLUSION

Patients older than 80 years develop anal cancer, but more often marginal tumors. Even in the oldest age group half of the patients can tolerate standard treatment by a combination of radiation and chemotherapy, and obtain a relative survival of 50% after five years. Fragile patients not considered candidates for chemoradiation may be offered radiation or resection to control local disease.

Regional variations in cancer survival: Impact of tumour stage, socioeconomic status, comorbidity and type of treatment in Norway

Cancer survival varies by place of residence, but it remains uncertain whether this reflects differences in tumour, patient and treatment characteristics (including tumour stage, indicators of socioeconomic status (SES), comorbidity and information on received surgery and radiotherapy) or possibly regional differences in the quality of delivered health care. National population-based data from the Cancer Registry of Norway were used to identify cancer patients diagnosed in 2002-2011 (n = 258,675). We investigated survival from any type of cancer (all cancer sites combined), as well as for the six most common cancers. The effect of adjusting for prognostic factors on regional variations in cancer survival was examined by calculating the mean deviation, defined by the mean absolute deviation of the relative excess risks across health services regions. For prostate cancer, the mean deviation across regions was 1.78 when adjusting for age and sex only, but decreased to 1.27 after further adjustment for tumour stage. For breast cancer, the corresponding mean deviations were 1.34 and 1.27. Additional adjustment for other prognostic factors did not materially change the regional variation in any of the other sites. Adjustment for tumour stage explained most of the regional variations in prostate cancer survival, but had little impact for other sites. Unexplained regional variations after adjusting for tumour stage, SES indicators, comorbidity and type of treatment in Norway may be related to regional inequalities in the quality of cancer care.

Long-term Relative Survival after Diagnosis of Testicular Germ Cell Tumor

BACKGROUND

Long-term relative survival (RS) data for testicular germ cell tumor (TGCT) patients are scarce. We aimed to analyze long-term RS among TGCT patients diagnosed in Norway, between 1953 and 2012.

METHODS

Data sources were the Cancer Registry of Norway and the Norwegian Cause of Death Registry. TGCT patients diagnosed during 1953 to 2012 were classified by time of diagnosis, histology, age, and disease extent at diagnosis. Estimates for RS were obtained, and a test comparing overall RS was performed. Corresponding data were obtained for men diagnosed with localized malignant melanoma before age 50.

RESULTS

A total of 8,736 TGCT patients were included. RS generally continued to decline with increasing follow-up time, particularly beyond 15 to 30 years, unlike in localized malignant melanoma. Although RS was generally higher for seminomas, the continuing decline was more pronounced than for nonseminomas, even when diagnosed with localized disease. TGCT patients diagnosed before 1980 or after age 40 had lower RS.

CONCLUSIONS

Although TGCT RS has improved in recent decades, it continues to decline even beyond 30 years of follow-up, regardless of disease extent at diagnosis. The main cause is probably treatment-induced late effects, particularly affecting seminoma patients. The continued use of adjuvant radiotherapy in seminomas until year 2000 is suspected as a culprit.

IMPACT

Long-term TGCT survivors should be closely monitored for the development of late comorbidity. The challenge is to reduce negative consequences of previous and current TGCT treatment on RS while maintaining the excellent cure rates. Further research on causes of long-term morbidity and mortality among TGCT survivors is warranted. Cancer Epidemiol Biomarkers Prev; 25(5); 773-9. ©2016 AACR.