Data quality at the Cancer Registry of Norway: An overview of comparability, completeness, validity and timeliness

Minimally Invasive Colorectal Cancer Surgery in Europe: Implementation and Outcomes

Minimally invasive surgery (MIS) of colorectal cancer (CRC) was first introduced over 20 years ago and recently has gained increasing acceptance and usage beyond clinical trials. However, data on dissemination of the method across countries and on long-term outcomes are still sparse.In the context of a European collaborative study, a total of 112,023 CRC cases from 3 population-based (N = 109,695) and 4 institute-based clinical cancer registries (N = 2328) were studied and compared on the utilization of MIS versus open surgery. Cox regression models were applied to study associations between surgery type and survival of patients from the population-based registries. The study considered adjustment for potential confounders.The percentage of CRC patients undergoing MIS differed substantially between centers and generally increased over time. MIS was significantly less often used in stage II to IV colon cancer compared with stage I in most centers. MIS tended to be less often used in older (70+) than in younger colon cancer patients. MIS tended to be more often used in women than in men with rectal cancer. MIS was associated with significantly reduced mortality among colon cancer patients in the Netherlands (hazard ratio [HR] 0.66, 95% confidence interval [CI] (0.63-0.69), Sweden (HR 0.68, 95% CI 0.60-0.76), and Norway (HR 0.73, 95% CI 0.67-0.79). Likewise, MIS was associated with reduced mortality of rectal cancer patients in the Netherlands (HR 0.74, 95% CI 0.68-0.80) and Sweden (HR 0.77, 95% CI 0.66-0.90).Utilization of MIS in CRC resection is increasing, but large variation between European countries and clinical centers prevails. Our results support association of MIS with substantially enhanced survival among colon cancer patients. Further studies controlling for selection bias and residual confounding are needed to establish role of MIS in survival of patients.

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.

Risk of Cancer in Children Conceived by Assisted Reproductive Technology

BACKGROUND AND OBJECTIVE

An increasing number of children are born after assisted reproductive technology (ART), and monitoring their long-term health effects is of interest. This study compares cancer risk in children conceived by ART to that in children conceived without.

METHODS

The Medical Birth Registry of Norway contains individual information on all children born in Norway (including information of ART conceptions). All children born between 1984 and 2011 constituted the study cohort, and cancer data were obtained from the Cancer Registry of Norway. Follow-up started at date of birth and ended on the date of the first cancer diagnosis, death, emigration, or December 31, 2011. A Cox proportional hazards model was used to calculate hazard ratios (HR) and 95% confidence intervals (CI) of overall cancer risk between children conceived by ART and those not. Cancer risk was also assessed separately for all childhood cancer types.

RESULTS

The study cohort comprised 1 628 658 children, of which 25 782 were conceived by ART. Of the total 4554 cancers, 51 occurred in ART-conceived children. Risk of overall cancer was not significantly elevated (HR 1.21; 95% CI 0.90-1.63). However, increased risk of leukemia was observed for children conceived by ART compared with those who were not (HR 1.67; 95% CI 1.02-2.73). Elevated risk of Hodgkin's lymphoma was also found for ART-conceived children (HR 3.63; 95% CI 1.12-11.72), although this was based on small numbers.

CONCLUSIONS

This population-based cohort study found elevated risks of leukemia and Hodgkin's lymphoma in children conceived by ART.

An assessment of GLOBOCAN methods for deriving national estimates of cancer incidence

OBJECTIVE

To assess the validity of the GLOBOCAN methods for deriving national estimates of cancer incidence.

METHODS

We obtained incidence and mortality data from Norway by region, year of diagnosis, cancer site, sex and 5-year age group for the period 1983-2012 from the NORDCAN database. Estimates for the year 2010 were derived using nine different methods from GLOBOCAN. These included the projection of national historical rates, the use of regional proxies and the combination of national mortality data with mortality to incidence ratios or relative survival proportions. We then compared the national estimates with recorded cancer incidence data.

FINDINGS

Differences between the estimates derived using different methods varied by cancer site and sex. Methods based on projections performed better where major changes in recent trends were absent. Methods based on mortality data performed less well for cancers associated with small numbers of deaths and for cancers detectable by screening. In countries with longstanding cancer registries of high quality, regional-based, or trends-based incidence estimates perform reasonably well in comparison with recorded incidence.

CONCLUSION

Although the performance of the GLOBOCAN methods varies by cancer site and sex in this study, the results emphasize a need for more high-quality population-based cancer registries - either regional or, where practical and feasible, national registries - to describe cancer patterns and trends for planning cancer control priorities.

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.

A national study on conditional survival, excess mortality and second cancer after high dose therapy with autologous stem cell transplantation for non-Hodgkin lymphoma

This national population-based study aimed to investigate conditional survival and standardized mortality ratios (SMR) after high-dose therapy with autologous stem-cell transplantation (HDT-ASCT) for non-Hodgkin lymphoma (NHL), and to analyse cause of death, relapses and second malignancies. All patients ≥18 years treated with HDT-ASCT for NHL in Norway between 1987 and 2008 were included (n = 578). Information from the Cause of Death Registry and Cancer Registry of Norway were linked with clinical data. The 5-, 10- and 20-year overall survival was 61% (95% confidence interval [CI] 56-64%), 52% (95%CI 48-56%) and 45% (95%CI 40-50%), respectively. The 5-year survival conditional on having survived 2, 5 and 10 years after HDT-ASCT was 81%, 86% and 93%. SMRs were 12·3 (95%CI 11·0-13·9), 4·9 (95%CI 4·1-5·9), 2·4 (95%CI 1·8-3·2) and 1·0 (95%CI 0·6-1·8) for the entire cohort and for patients having survived 2, 5 and 10 years after HDT-ASCT respectively. Of the 281 deaths observed, 77% were relapse-related. Treatment-related mortality was 3·6%. The 10-year cumulative incidence of second malignancies was 7·9% and standardized incidence ratio was 2·0 (95%CI 1·5-2·6). NHL patients treated with HDT-ASCT were at increased risk of second cancer and premature death. The mortality was still elevated at 5 years, but after 10 years mortality equalled that of the general population.

Effect of organised mammography screening on stage-specific incidence in Norway: population study

Background:

We aimed to estimate the effect of organised mammography screening on breast cancer stage distribution by comparing changes in women eligible for screening, based on birth cohort, to the concurrent changes in younger, ineligible women.

Methods:

In an open cohort study in Norway, which introduced national mammography screening county-by-county from 1995 to 2004, we identified women (n=49 883) diagnosed with in situ or invasive breast cancer (ICD10 codes: D05 or C50) during the period 1987–2011 and born between 1917 and 1980. We estimated relative incidence rate ratios (rIRRs) comparing the development in the screening vs historic group to the younger vs younger historic group.

Results:

Including the compensatory drop, eligible women experienced a 68% higher increase in localised cancers (rIRR=1.68, 95% confidence interval (CI): 1.51–1.87) than younger women, while the increase in incidence of advanced cancers was similar (rIRR=1.11, 95% CI: 0.90–1.36). Excluding the prevalence round, eligible women experienced a 60% higher increase in localised cancers (rIRR=1.60, 95% CI: 1.42–1.79), while the increase in incidence of advanced cancers remained similar (rIRR=1.08, 95% CI: 0.86–1.35).

Conclusions:

Introduction of organised mammography screening was followed by a significant increase in localised and no change in advanced-stage cancers in women eligible for screening relative to younger, ineligible women.

Reproduction and marriage among male survivors of cancer in childhood, adolescence and young adulthood: a national cohort study

BACKGROUND

Increased survival after cancer in young age has made long-term follow-up studies of high external validity important. In this national cohort study, we explored the impact of cancer in young age on reproduction and marital status in male survivors.

METHODS

Hazard ratios (HRs) and relative risks (RRs) of reproductive and marital outcomes were studied for male survivors of cancer in young age (<25 years) and cancer-free male comparisons, born during 1965-1985, by linking compulsory national registries in Norway.

RESULTS

Male cancer survivors (n=2687) had reduced paternity (HR: 0.72, 95% confidence interval (CI): 0.68-0.76). This was most apparent in survivors of testicular cancer, brain tumours, lymphoma, leukemia and bone tumours, and when diagnosed with cancer before 15 years of age. Male cancer survivors were more likely to avail of assisted reproduction (RR: 3.32, 95% CI: 2.68-4.11). There was no increased risk of perinatal death, congenital malformations, being small for gestational age, of low birth weight or preterm birth in their first offspring. Male cancer survivors were less likely to marry (HR: 0.93, 95% CI: 0.86-1.00), in particular brain tumour survivors.

CONCLUSIONS

In this national cohort study, we demonstrated reduced paternity and increased use of assisted reproduction among male cancer survivors, but no adverse outcome for their first offspring at birth.

Epithelial ovarian cancer subtypes attributable to smoking in the Norwegian Women and Cancer Study, 2012

Among European women, ovarian cancer is the fifth most common cancer. Smoking is an established risk factor for mucinous tumors. We estimated the impact of smoking in Norwegian women using population attributable fractions (PAFs) of epithelial ovarian cancer (EOC), by invasiveness and by histological subtypes in the Norwegian Women and Cancer Study with an average of 13.2 years of follow‐up. During >2 million person‐years, a total of 915 incident EOC cases, of which 667 (73%) invasive and 248 (27%) borderline, were identified among 154,234 women aged 34–70 years at enrolment. Compared with never smokers, current smokers had a nonstatistically significant increased risk of mucinous tumors (hazard ratio [HR] = 1.67 [95% confidence interval, (CI), 0.96–2.96]) and more than twice statistically significant risk of borderline mucinous tumors (HR = 2.17 [95% CI, 1.06–4.45]). The corresponding PAF estimates were 16.5% for mucinous and 25% for borderline mucinous. We found that among middle‐aged women, one in six mucinous tumors and one in four borderline mucinous tumors could have been prevented if women did not smoke.

Consumption of Whole-Grain Bread and Risk of Colorectal Cancer among Norwegian Women (the NOWAC Study)

There is evidence that consumption of foods containing dietary fiber decreases the risk of colorectal cancer (CRC). Whole grains contain dietary fiber, as well as a range of micronutrients and bioactive compounds, but the association between the consumption of whole grains and the risk of CRC remains less studied. The aim of the present study was to investigate the association between whole-grain bread consumption and CRC incidence among Norwegian women, using data from a prospective cohort study (the Norwegian Women and Cancer Study). Dietary intake was estimated from the food-frequency questionnaires of 78,254 women in the cohort (median age: 55 years), and these women were then followed up for CRC incidence. During the 9 years of median follow-up, 795 women were diagnosed with CRC (316 proximal, 193 distal, 218 rectal). Associations between whole-grain bread consumption and the risk of CRC (including colorectal subsites) were investigated using Cox proportional hazards regression models. When compared to the low consumption group, the hazard ratio for CRC was 0.89 (95% confidence interval (CI): 0.72-1.09) for the high consumption group and 0.86 (95% CI: 0.72-1.02) for the medium consumption group in a multivariable model. Overall, no association between whole-grain bread consumption and CRC was found.

Pre-diagnostic high-sensitive C-reactive protein and breast cancer risk, recurrence, and survival

Inflammation may initiate and promote breast cancer development, and be associated with elevated circulating levels of inflammation markers. A total of eight 130 initially healthy women, participated in the population-based Tromsø study (1994-2008). Pre-diagnostic high-sensitivity C-reactive protein (hs-CRP) was assessed. During 14.6 years of follow-up, a total of 192 women developed invasive breast cancer. These cases were followed for additional 7.2 years. Detailed medical records were obtained. We observed an overall positive dose-response relationship between pre-diagnostic hs-CRP and breast cancer risk (hazard ratio (HR) = 1.06, 95 % CI 1.01-1.11). Postmenopausal women with above median levels of hs-CRP (>1.2 mg/l) had a 1.42 (95 % CI 1.01-2.00) higher breast cancer risk compared to postmenopausal women with hs-CRP below median. Postmenopausal women, who were hormone replacement therapy non-users, and were in the middle tertile (0.8-1.9 mg/l), or highest tertile of hs-CRP (>1.9 mg/l), had a 2.31 (95 % CI 1.31-4.03) and 2.08 (95 % CI 1.16-3.76) higher breast cancer risk, respectively, compared with women in the lowest tertile. For each unit increase in pre-diagnostic hs-CRP levels (mg/l), we observed an 18 % increase in disease-free interval (95 % CI 0.70-0.97), and a 22 % reduction in overall mortality (95 % CI 0.62-0.98). Our study supports a positive association between pre-diagnostic hs-CRP and breast cancer risk. In contrast, increased pre-diagnostic hs-CRP was associated with improved overall mortality, but our findings are based on a small sample size, and should be interpreted with caution.

The outcome and the frequency of pathological complete response after neoadjuvant radiotherapy in curative resections for advanced rectal cancer: a population-based study

AIM

Pathological complete response (ypCR) after neoadjuvant treatment for rectal cancer is associated with favourable survival and a low rate of local recurrence. The aim of the study was to assess the incidence of ypCR among patients with advanced rectal cancer treated with neoadjuvant chemoradiotherapy and curative resection and to explore factors associated with survival.

METHOD

From 2000 to 2009, 1384 patients enrolled in the national population- based colorectal cancer registry of Norway with advanced T3 and T4 rectal cancer with N0-2, M0 received neoadjuvant long-course (chemo)radiation. The duration of follow-up was a median of 5 years.

RESULTS

ypCR was achieved in 147 (10.6%) patients. The estimated 5-year overall survival rate was 87% (confidence interval ± 5.4) among ypCR and 67% among non-ypCR (confidence interval ± 2.7) (P < 0.0001). Distant metastasis developed in 12 (8%) of 147 and 328 (26.5%) of 1237 patients respectively (P < 0.001). In a Cox proportional hazards ratio model the effect of ypCR on survival was adjusted for age [hazard ratio (HR) 1.056, P = 0.0001], metachronous metastasis (HR 4.7, P = 0.0001), local recurrence (HR 4.3, P = 0.0001) and surgical procedure (HR 1.48, P = 0.0001). The independent effect of ypCR (HR 0.65, P = 0.041) on survival almost disappeared compared with the univariate analysis.

CONCLUSION

The rate of ypCR in advanced rectal cancer was about 10%. This phenomenon seems to occur in tumours with a low risk of metastasizing. The contribution of neoadjuvant therapy to ypCR on survival was small or absent.

Clinicopathological significance of increased ZIC1 expression in human endometrial cancer

Zinc finger of the cerebellum (ZIC1), one of ZIC family genes, has been shown to play important roles in many cancers such as gastric cancer and breast cancer. However, there is little known about the expression and significance of ZIC1 in endometrial cancer. The aim of this study was to determine the expression pattern and clinicopathological significance of ZIC1 in endometrial cancer. The mRNA and protein expression of ZIC1 in endometrial cancer tissues was detected using the reverse-transcription polymerase chain reaction and Western blotting, respectively. Immunostaining of ZIC1 in 99 endometrial cancer samples was examined and its associations with clinicopathological parameters were analyzed. Hec-1-B cells were transfected with ZIC1-shRNA or sc-shRNA, and cell proliferation was assayed. Hec-1-B cells stably transfected with ZIC1-shRNA or sc-shRNA were subcutaneously inoculated into nude mice, and the tumor weight was measured. A significantly increased expression of ZIC1 mRNA and protein was observed in endometrial cancer tissues compared to that in normal endometrial tissues (P<0.05). Immunohistochemical analysis showed that strong cytoplasmic immunostaining of ZIC1 was observed in almost all endometrial cancer samples (90/99) while light and moderate immunostaining of ZIC1 was only detected in 17 of 30 (56.7%) normal tissues. Moreover, up-regulation of ZIC1 was significantly correlated with age, disease stage, TNM stage and FIGO stage (P<0.05). The down-regulated expression of ZIC1 contributed to the inhibition of cell proliferation, and inhibited the growth of tumor. It was concluded that ZIC1 is over-expressed in endometrial cancer tissue but not in normal tissue, and positively correlated to the malignant biological behavior of endometrial carcinogenesis.

Metabolic syndrome and esophageal and gastric cancer

BACKGROUND

The role of the metabolic syndrome in the etiology of esophageal and gastric cancer is unclear.

METHODS

This was a large nationwide cohort study based on data from 11 prospective population-based cohorts in Norway with long-term follow-up, the Cohort of Norway (CONOR) and the third Nord-Trøndelag Health Study (HUNT3). The metabolic syndrome was assessed by objective anthropometric and metabolic biochemical measures and was defined by the presence of at least three of the following five factors: increased waist circumference, elevated triglycerides, low high-density lipoprotein cholesterol, hypertension and high glucose. Newly diagnosed cases of esophageal adenocarcinoma, esophageal squamous-cell carcinoma and gastric adenocarcinoma were identified from the Norwegian Cancer Registry. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazard models with adjustment for potential confounders.

RESULT

Among 192,903 participants followed up for an average of 10.6 years, 62 developed esophageal adenocarcinoma, 64 had esophageal squamous-cell carcinoma and 373 had gastric adenocarcinoma. The metabolic syndrome was significantly associated with an increased risk of gastric adenocarcinoma (HR 1.44, 95% CI 1.14-1.82), but not associated with esophageal adenocarcinoma (HR 1.32, 95% CI 0.77-2.26) or esophageal squamous-cell carcinoma (HR 1.08, 95% CI 0.64-1.83). Increased waist circumference was associated with an increased HR of esophageal adenocarcinoma (HR 2.48, 95% CI 1.27-4.85). No significant association was found between any single component of the metabolic syndrome and risk of esophageal squamous-cell carcinoma. High waist circumference (HR 1.71, 95% CI 1.05-2.80), hypertension (HR 2.41, 95% CI 1.44-4.03) and non-fasting glucose (HR 1.74, 95% CI 1.18-2.56) were also related to an increased risk of gastric adenocarcinoma in women, but not in men.

CONCLUSION

Metabolic syndrome was associated with an increased risk of gastric adenocarcinoma in women. Of the individual components of the metabolic syndrome, high waist circumference was positively associated with risk of esophageal adenocarcinoma. Positive associations were also observed for women between high waist circumference, hypertension, high non-fasting glucose and risk of gastric adenocarcinoma. However, further evidence is warranted due to the limited number of cases and the inability to effectively identify gastric cardia adenocarcinoma.

The Adult Life After Childhood Cancer in Scandinavia (ALiCCS) Study: Design and Characteristics

BACKGROUND

During the last five decades, survival of childhood cancer has increased from 25% to 80%. At the same time, however, it has become evident that survivors experience a broad range of therapy-related late adverse health effects. The aim of the Adult Life after Childhood Cancer in Scandinavia (ALiCCS) study is to investigate long-term health consequences of past and current therapies in order to improve follow-up care of survivors and to reduce treatment-related morbidity of future patients.

PROCEDURE

Childhood cancer survivors were identified through the five Nordic cancer registries and a comparison cohort was established through random selection of cancer-free individuals from the civil registration systems. A unique personal identification number was used to link between different health registries. Abstraction of treatment information for a subset of survivors allows investigation of the association between the various components of cancer therapy and late occurring comorbidity.

RESULTS

The childhood cancer survivor cohort comprises 33,160 1-year survivors and the comparison cohort comprises 212,892 cancer free individuals from the general population. In the childhood cancer survivor cohort, all types of childhood cancer are represented including leukemia (21%), lymphoma (14%), central nervous system tumors (24%), sarcomas (5%), retinoblastoma (3%), and neuroblastoma (4%). Among the survivors, 22% have been followed beyond the age of 40 years.

CONCLUSION

The ALiCCS study constitutes a new large resource for research on late effects of childhood cancers that include all types of childhood malignancies and has followed a large proportion of the survivors well into late adulthood.

Positive predictive values by mammographic density and screening mode in the Norwegian Breast Cancer Screening Program

OBJECTIVE

To investigate the probability of breast cancer among women recalled due to abnormal findings on the screening mammograms (PPV-1) and among women who underwent an invasive procedure (PPV-2) by mammographic density (MD), screening mode and age.

METHODS

We used information about 28,826 recall examinations from 26,951 subsequently screened women in the Norwegian Breast Cancer Screening Program, 1996-2010. The radiologists who performed the recall examinations subjectively classified MD on the mammograms into three categories: fatty (<30% fibroglandular tissue); medium dense (30-70%) and dense (>70%). Screening mode was defined as screen-film mammography (SFM) and full-field digital mammography (FFDM). We examined trends of PPVs by MD, screening mode and age. We used logistic regression to estimate odds ratio (OR) of screen-detected breast cancer associated with MD among women recalled, adjusting for screening mode and age.

RESULTS

PPV-1 and PPV-2 decreased by increasing MD, regardless of screening mode (p for trend <0.05 for both PPVs). PPV-1 and PPV-2 were statistically significantly higher for FFDM compared with SFM for women with fatty breasts. Among women recalled, the adjusted OR of breast cancer decreased with increasing MD. Compared with women with fatty breasts, the OR was 0.90 (95% CI: 0.84-0.96) for those with medium dense breasts and 0.85 (95% CI: 0.76-0.95) for those with dense breasts.

CONCLUSION

PPVs decreased by increasing MD. Fewer women needed to be recalled or undergo an invasive procedure to detect one breast cancer among those with fatty versus dense breasts in the screening program in Norway, 1996-2010.

COPD and risk of venous thromboembolism and mortality in a general population

The relationship between chronic obstructive pulmonary disease (COPD) and risk of venous thromboembolism (VTE) has been scarcely studied in the general population. We aimed to investigate the association between COPD and risk of VTE and mortality in a population-based cohort.Spirometry was conducted in 8646 males and females, participating in the fifth (2001-02) and sixth (2007-08) surveys of the Tromsø Study. Incident VTE events during follow-up were registered from the date of inclusion to December 31, 2011. Cox-regression models with COPD stages and confounders as time varying covariates were used to calculate hazard ratios with 95% confidence intervals for VTE and all-cause mortality.During a median follow-up of 6.2 years, 215 subjects developed VTE. Subjects with COPD stage III/IV had a two-fold higher risk of secondary VTE compared to subjects with normal airflow (HR 2.05, 95% CI 1.02-4.10). COPD patients, particularly those with stage III/IV disease, with VTE had a higher mortality rate than COPD patients without VTE (50.2% versus 5.6% per year).Our findings suggest that patients with severe COPD may have increased risk of secondary VTE, and that COPD patients with VTE have a higher mortality rate than COPD patients without VTE.

Mode of detection: an independent prognostic factor for women with breast cancer

OBJECTIVES

To investigate breast cancer survival and risk of breast cancer death by detection mode (screen-detected, interval, and detected outside the screening programme), adjusting for prognostic and predictive tumour characteristics.

METHODS

Information about detection mode, prognostic (age, tumour size, histologic grade, lymph node status) and predictive factors (molecular subtypes based on immunohistochemical analyses of hormone receptor status (estrogen and progesterone) and Her2 status) were available for 8344 women in Norway aged 50-69 at diagnosis of breast cancer, 2005-2011. A total of 255 breast cancer deaths were registered by the end of 2011. Kaplan-Meier method was used to estimate six years breast cancer specific survival and Cox proportional hazard model to estimate hazard ratio (HR) for breast cancer death by detection mode, adjusting for prognostic and predictive factors.

RESULTS

Women with screen-detected cancer had favourable prognostic and predictive tumour characteristics compared with interval cancers and those detected outside the screening programme. The favourable characteristics were present for screen-detected cancers, also within the subtypes. Adjusted HR of dying from breast cancer was two times higher for women with symptomatic breast cancer (interval or outside the screening), using screen-detected tumours as the reference.

CONCLUSIONS

Detection mode is an independent prognostic factor for women diagnosed with breast cancer. Information on detection mode might be relevant for patient management to avoid overtreatment.

Cancer patients' participation in population-based health surveys: findings from the HUNT studies

Background

The magnitude of participation bias due to non-participation should be considered for cancer patients invited to population-based surveys. We studied participation rates among persons with and without cancer in a large population based study, the Nord-Trøndelag Health Study (HUNT).

Methods

Citizens 20 years or above living in the Nord-Trøndelag County of Norway have been invited three times to comprehensive health surveys. The invitation files with data on sex, invitation date and participation were linked to the Cancer Registry of Norway. In a first step unadjusted crude participation rates (participants/invited persons) were estimated for cancer patients (CaPts) and non-cancer persons (NonCaPers), followed by logistic regression analyses with adjustment for age and sex. To evaluate the “practical” significance of the estimated odds ratios in the cancer diagnosis group, relative risks were also estimated comparing the observed rates to the estimated rates under the counterfactual assumption of no earlier cancer diagnosis among CaPts.

Results

Overall 3 % of the participants in the three HUNT studies were CaPts and 59 % of them had been diagnosed with their first life-time cancer >5 years prior to each survey. In each of the three HUNT surveys crude participation rates were similar for CaPts and NonCaPers. Adjusted for sex and age, CaPts’ likelihood to participate in HUNT1 (1984–86) and HUNT2 (1995–97), but not in HUNT3 (2006–2008), was statistically significantly reduced compared to NonCaPers, equaling a relative risk of 0.98 and 0.96, respectively. The lowest odds ratio emerged for CaPts diagnosed during the last 2 years preceding a HUNT invitation. Only one-third of CaPts participating in a survey also participated in the subsequent survey compared to approximately two-thirds of NonCaPers, and 11 % of CaPts participated in all three HUNT surveys compared to 37 % of NonCaPers.

Conclusion

In the three HUNT surveys no or only minor participation bias exist as to CaPts’ participation rates. In longitudinal studies selection bias as to long-term cancer survivorship should be taken into account, the percentage of repeatedly participating CaPts diminishing more strongly than among NonCaPers.

Lung cancer survival in Norway, 1997-2011: from nihilism to optimism

We examine changes in survival and patient-, tumour- and treatment-related factors among resected and nonresected lung cancer patients, and identify subgroups with the largest and smallest survival improvements.National population-based data from the Cancer Registry of Norway, Statistics Norway and the Norwegian Patient Register were linked for lung cancer patients diagnosed during 1997-2011. The 1- and 5-year relative survival were estimated, and Cox proportional hazard regression, adjusted for selected patient characteristics, was used to assess prognostic factors for survival in lung cancer patients overall and stratified by resection status.We identified 34 157 patients with lung cancer. The proportion of histological diagnoses accompanied by molecular genetics testing increased from 0% to 26%, while those accompanied by immunohistochemistry increased from 8% to 26%. The 1-year relative survival among nonresected and resected patients increased from 21.7% to 34.2% and 75.4% to 91.5%, respectively. The improved survival remained significant after adjustment for age, sex, stage and histology. The largest improvements in survival occurred among resected and adenocarcinoma patients, while patients ≥80 years experienced the smallest increase.Lung cancer survival has increased considerably in Norway. The explanation is probably multifactorial, including improved attitude towards diagnostic work-up and treatment, and more accurate diagnostic testing that allows for improved selection for resection and improved treatment options.

Lung cancer – changes in incidence by gender, age and county of residence 1984-2013

BACKGROUND

The Cancer Registry of Norway has reported a decline in age-standardised lung cancer rates for men and an unconfirmed levelling-off in the rate for women. This study describes the development in trends according to gender and age, nationwide as well as by county.

MATERIAL AND METHOD

Data on lung cancer from the Cancer Registry of Norway and the NORDCAN website are presented as age-specific and age-standardised rates by gender and place of residence, with a main emphasis on the period 1984-2013.

RESULTS

Out of 62,937 Norwegian lung cancer patients (1984-2013), altogether 63% were men. Nationally there was a decline in the rate for middle-aged men (50-69 years), but only a levelling-off in the oldest age group (≥ 70 years). For women, the rates increased in both age groups, most markedly in the oldest one. The rates for older men in the Agder, Vestfold and Finnmark counties have remained above the national average for a prolonged period, and there are only modest signs of a decline among the middle-aged. Oslo is a clear exception, with a clear and sustained decline among men in both age groups. Vest-Agder county had the highest rate for women during the last five-year period, while the rates in Oslo are now at the national average. The national rates for middle-aged women and middle-aged men are converging, intersecting each other in Akershus county.

INTERPRETATION

The large differences between genders, age groups, counties and nations in terms of trends in lung cancer indicate that through preventive efforts, we might have achieved much more in a shorter time.

Nationwide improvement of rectal cancer treatment outcomes in Norway, 1993-2010

BACKGROUND

The Norwegian Rectal Cancer Project was initated in 1993 with the aims of improving surgery, decreasing local recurrence rates, improving survival, and establishing a national rectal cancer registry. Here we present results from the Norwegian Colorectal Cancer Registry (NCCR) from 1993 to 2010.

MATERIAL AND METHODS

A total of 15 193 patients were diagnosed with rectal cancer in Norway 1993-2010, and were registered with clinical data regarding diagnosis, treatment, locoregional recurrences and distant metastases. Of these, 10 796 with non-metastatic disease underwent tumour resection. The results were stratified into five time periods, and the treatment outcomes were compared. Recurrence rates are presented for the 9785 patients who underwent curative major resection (R0/R1).

RESULTS

Among all 15 193 patients, relative five-year survival increased from 54.1% in 1993-1997 to 63.4% in 2007-2010 (p < 0.001). Among the 10 796 patients with stage I-III disease who underwent tumour resection, from 1993-1997 to 2007-2010, relative five-year survival improved from 71.2% to 80.6% (p < 0.001). An increasing proportion of these patients underwent surgery at large-volume hospitals; and 30- and 100-day mortality rates, respectively, decreased from 3.0% to 1.4% (p < 0.001) and from 5.1% to 3.0% (p < 0.011). Use of preoperative chemoradiotherapy increased from 6.5% in 1993 to 39.0% in 2010 (p < 0.001). Estimated local recurrence rate after major resection (R0/R1) decreased from 14.5% in 1993-1997 to 5.0% in 2007-2009 (p < 0.001), and distant recurrence rate decreased from 26.0% to 20.2% (p < 0.001).

CONCLUSION

Long-term outcomes from a national population-based rectal cancer registry are presented. Improvements in rectal cancer treatment have led to decreased recurrence rates of 5% and increased survival on a national level.

Validity of Norwegian Rectal Cancer Registry data at a major university hospital 1997-2005

BACKGROUND

The Norwegian Rectal Cancer Registry (NRCR) has been used extensively to monitor patient treatment and outcomes since its establishment in 1993. Control of data validity is crucial to ensure reliable information, but an audit of the NRCR data validity has not been performed so far. This study aims to validate NRCR data on patients diagnosed in the period 1997-2005, Department of Surgery, Haukeland University Hospital.

MATERIAL AND METHODS

The material comprises NRCR data on all 482 patients diagnosed with rectal cancer in the period 1997-2005 at a major Norwegian university hospital. We checked 50 variables for discrepancies by comparing NRCR data with the medical records. All erroneous registrations were recorded.

RESULTS

One hundred patients (21%) had one or more data discrepancies in the registry, and 131 errors (0.5%) were noted in total. Sixteen variables (32%) had no erroneous registrations. Pre-operative CT and type of surgical procedure had the highest proportion of erroneous registrations (2.1%). Recorded errors were grouped into five variable categories: Pre-operative evaluation and adjuvant treatment (40 errors), surgical treatment (44 errors), pathological evaluation (20 errors), complications (7 errors) and oncological outcomes (20 errors). The majority of erroneous registrations (45%) were considered minor in severity, 27% were moderate and 28% were major.

CONCLUSION

Assessment of the NRCR data from a nine-year period showed a good data validity in this hospital cohort.

HE4 as an Early Detection Biomarker of Epithelial Ovarian Cancer: Investigations in Prediagnostic Specimens From the Janus Serumbank

OBJECTIVES

Epithelial ovarian cancer is characterized by nonspecific signs and clinical symptoms arising at late stages. Early detection is therefore important and may significantly improve the survival rate. Cancer antigen 125 (CA125) has been the most extensively studied serum biomarker in epithelial ovarian cancer, but low specificity limits its usefulness. A relatively novel biomarker, human epididymis protein 4 (HE4), has shown promise in early detection of the disease. The aim of this study was to investigate how early the tumor marker increases before diagnosis.

METHODS/MATERIALS

A nested case-control design was used to evaluate the performance of HE4 and CA125 in prediagnostic serum samples from the Janus Serumbank. Serial specimens from 120 women with invasive epithelial ovarian cancer were compared with healthy controls. Serum level of CA125, HE4, and cotinine was measured. Spearman correlation and multiple linear regression analyses were used to investigate impact of smoking, age, storage time, and lag time (time from sampling until date of diagnosis).

RESULTS

Spearman correlation showed a strong positive correlation between HE4 and smoking in both cases and controls. Multiple linear regression analyses for pairwise differences between case and control showed that serum level of HE4 and CA125 was significantly increased (P = 0.002 and P < 0.001, respectively) 2 years before diagnosis and that CA125 also was significantly increased up to 4 years before diagnosis (P = 0.002).

CONCLUSIONS

The present study showed that a difference between cases and controls in serum concentration of HE4 seemed to be increased 2 years before diagnosis and that CA125 was increased until 4 years before diagnosis.

Strategies to Maximize Data Collection Response Rates in a Randomized Control Trial Focused on Children with Medical Complexity

INTRODUCTION

Obtaining complete and timely subject data is key to the success of clinical trials, particularly for studies requiring data collected from subjects at home or other remote sites. A multifaceted strategy for data collection in a randomized controlled trial (RCT) focused on care coordination for children with medical complexity is described. The influences of data collection mode, incentives, and study group membership on subject response patterns are analyzed. Data collection included monthly healthcare service utilization (HCSU) calendars and annual surveys focused on care coordination outcomes.

MATERIALS AND METHODS

One hundred sixty-three families were enrolled in the 30-month TeleFamilies RCT. Subjects were 2-15 years of age at enrollment. HCSU data were collected by parent/guardian self-report using mail, e-mail, telephone, or texting. Surveys were collected by mail. Incentives were provided for completed surveys after 8 months to improve collection returns. Outcome measures were the number of HCSU calendars and surveys returned, the return interval, data collection mode, and incentive impact.

RESULTS

Return rates of 90% for HCSU calendars and 82% for annual surveys were achieved. Mean return intervals were 72 and 65 days for HCSU and surveys, respectively. Survey response increased from 55% to 95% after introduction of a gift card and added research staff.

CONCLUSIONS

High return rates for HCSU calendars and health-related surveys are attainable but required a flexible and personnel-intensive approach to collection methods. Family preference for data collection approach should be obtained at enrollment, should be modified as needed, and requires flexible options, training, intensive staff/family interaction, and patience.

Supplemental folic acid in pregnancy and maternal cancer risk

BACKGROUND

There is evidence that increased intake of folate protects against the development of several types of cancer. Some studies have, however, raised concern about the safety of folate in relation to cancer risk. Here we examined the risk of maternal cancer after intake of supplemental folic acid in pregnancy.

METHODS

This is a population-based cohort study comprising 429,004 women with data from the Medical Birth Registry of Norway, the Cancer Registry of Norway, and other national registries from 1999 to 2010. Altogether 3781 cancer cases were identified during follow-up (average 7 years). Cox proportional hazards regression models were used to estimate hazard ratios of maternal cancer according to folic acid use prior to and during one or two or more pregnancies as compared to no supplement use.

RESULTS

Folic acid supplementation use had no overall effect on cancer risk in women using folic acid supplementation in one (HR 1.08; 95% CI 1.00-1.18) or two or more pregnancies (HR 1.06; 95% CI 0.91-1.22) (ptrend=0.12). Analyses of 13 cancer types revealed no associations between folic acid and cancer.

CONCLUSION

Folic acid supplementation before and during pregnancy had no overall effect on maternal cancer risk.

IMPACT

Folic acid substitution before and/or during pregnancy does not increase the short-term overall maternal cancer risk.

A Nation-Wide Cancer Registry-Based Study of Adenosquamous Carcinoma in Taiwan

BACKGROUND

Adenosquamous carcinoma (ASC) is a rare disease involving various organs, yet there are no large-scale population-based comparative studies on ASC among different organs.

METHODS

The incidence and overall survival of ASC among various organs in cases diagnosed in Taiwan from January 1, 2003 to December 31, 2010 were calculated and compared using data from the Taiwan Cancer Registry (TCR). The various organs were classified and divided into three different systems: the female reproductive, respiratory, and alimentary systems. Survival analysis were also compared among 30,850 patients diagnosed as ASC, adenocarcinoma (AC) or squamous cell carcinoma (SCC) in organs with frequent ASC.

RESULTS

During the study period, a total of 576 ASC cases were diagnosed in Taiwan. The most common primary system was respiratory (73.8%), followed by alimentary (16.2%) and female reproductive (10%). The overall survival were significantly higher for cases involving the female reproductive system, followed by the respiratory and alimentary systems (P = 0.016). The median overall survival were worse in males than females for cases involving the respiratory system (22.4 vs. 31.8 months, P = 0.044). Multivariate analysis showed that age ≧ 65, more advanced T and N categories were independent unfavorable prognostic factors of overall survival in ASC. ASC histology is an independent unfavorable prognostic factor compared with AC and SCC.

CONCLUSIONS

ASC at an old age and more advanced T and N categories were found to be associated with a poor prognosis.

Body mass index, diabetes and survival after diagnosis of endometrial cancer: A report from the HUNT-Survey

OBJECTIVE

We studied the association of body mass index (BMI) and diabetes with all-cause death and endometrial cancer-specific death among women with endometrial cancer (EC).

METHODS

Included were 337 women in the Health Surveys in North-Trøndelag, Norway who were followed from EC diagnosis to death or end of follow-up, 30th June 2012. Risks of death associated with BMI and diabetes were estimated as hazard ratios (HRs) with 95% confidence intervals (95% CI). The risks of EC-specific death were estimated as sub-HRs, after adjustment for competing causes of death. We also studied the risk of death associated with diabetes in women with BMI<25kg/m(2) and in women with BMI≥25kg/m(2).

RESULTS

During the median follow-up time of 6.7years, 166 women (49.3%) died. Diabetes increased the risk of all-cause death (HR 2.14, 95% CI: 1.26-3.63) and endometrial cancer-specific death (SHR, 2.62, 95% CI: 1.07-6.43) after adjustment for age, histological type and stage of EC. BMI was not associated with risk of all-cause or EC-specific death. The increased risk of both all-cause death and EC specific death in diabetic women seemed to be more pronounced in women with BMI<25kg/m(2) (HR 6.35, 95% CI: 1.90-21.14) compared to women with BMI>25kg/m(2) (HR 1.80, 95% CI: 0.98-3.33).

CONCLUSIONS

Diabetes, but not BMI, was associated with increased risk of all-cause death and death from EC. The increased risk of death associated with diabetes seemed to be most pronounced in women with BMI<25kg/m(2).

Existing data sources in clinical epidemiology: the Scandinavian Thrombosis and Cancer Cohort

Background

Although venous thromboembolism (VTE) is a known common complication in cancer patients, there is limited knowledge on patient-related and cancer-specific risk factors in the general population. The Scandinavian Thrombosis and Cancer (STAC) Cohort was established by merging individual data from three large Scandinavian cohorts (The Tromsø Study, the second Nord-Trøndelag Health Study, and the Danish Diet, Cancer and Health Study). Here, we present the profile of the STAC cohort and provide age-specific incidence rates of VTE and cancer.

Methods

The STAC cohort includes 144,952 subjects aged 19–101 years without previous VTE or cancer. Baseline information collected in 1993–1997 included physical examination, self-administered questionnaires, and blood samples. Validated VTE events and cancer diagnoses were registered up to 2007–2012.

Results

There were 2,444 VTE events (1.4 per 1,000 person-years [PY]) during follow-up, and the incidence increased exponentially from 0.3 per 1,000 PY in subjects aged 20–29 years to 6.4 per 1,000 PY in subjects aged 80+. Overall, 51% of the VTE events were provoked, and cancer was the most common provoking factor (19%), followed by immobilization and surgery (both 15%). In total, 19,757 subjects developed cancer during follow-up (9.8 per 1,000 PY), and the 5-year age-specific incidence rates of cancer were coherent with corresponding rates from the Norwegian Cancer Registry.

Conclusion

The STAC cohort will provide a unique opportunity to explore the epidemiology and impact of genetic and environmental patient-related and cancer-specific risk factors for VTE in the general population.

Postmenopausal hormone therapy and the risk of breast cancer in Norway

There is convincing evidence that combined estrogen-progestin therapy (EPT) increases the risk of breast cancer. However, the effect of different formulations, preparations and routes of administration is largely unknown. Estrogen only-therapy (ET) is, in general, not associated or weakly associated with breast cancer risk. We investigated the effect of hormone therapy (HT) with ET, EPT, and tibolone on risk of invasive breast cancer. Information on HT use was obtained from the Norwegian Prescription Database, and breast cancer incidence from the Cancer Registry of Norway. Poisson regression was used to estimate the incidence rate ratios (RR). We analyzed data from 686,614 Norwegian women, aged 45-79 years in January 2004, followed until December 2008, of whom 178,383 (26%) were prescribed HT. During the average 4.8 years of follow-up, 7,910 invasive breast cancers were registered. Compared with nonusers, current users of estradiol-norethisterone acetate (NETA)(EPT) had a RR of 2.74 (95% CI: 2.55-2.95). Users of the high dose estradiol-NETA formulation Kliogest(®) had a RR of 3.26 (95% CI: 2.84-3.73), while users of the low dose Activelle(®) had a RR of 2.76 (95% CI: 2.51-3.04). Current users of tibolone had a RR of 1.91 (95% CI: 1.61-2.28). Current users of ET with oral or transdermal estradiol had a RR of 1.40 (95% CI: 1.16-1.68), and 1.40 (95% CI: 1.00-1.95), respectively. The increased incidence rates approximates one extra invasive breast cancer case diagnosed for every 259 women using estradiol-NETA for one year, and one extra case for every 475 women using tibolone. In conclusion, use of estradiol-NETA and tibolone preparations is associated with an increased breast cancer risk.

The prospective association between health anxiety and cancer detection: A cohort study linking the Hordaland Health Study (HUSK) with the Norwegian Cancer Registry

OBJECTIVE

Health anxiety is associated with distress and disability, and overutilization of health services, but it is not known whether high levels of health anxiety may lead to increased detection of severe diseases such as cancer. By linking a large population based health study with the national cancer registry, the aim of the study was to investigate a potential prospective association between health anxiety in men and women and later cancer detection and tumour metastasis at the time of diagnosis.

METHOD

A longitudinal study with a 13.2 year follow-up linking the population-based Hordaland Health Study (HUSK) and the Cancer Registry of Norway (CRN) was conducted. Health anxiety was measured with the Whiteley Index. Associations were examined through gender stratified Cox regression analyses adjusted for relevant covariates.

RESULTS

No association was found between baseline health anxiety and cancer detection for women (adjusted HR: 1.21, 95% CI: 0.42-3.50), but a positive association was found between health anxiety at baseline and cancer detection for men (adjusted HR: 1.76, 95% CI: 1.06-2.91). No statistically significant association was demonstrated between health anxiety and cancer metastasis for either gender.

CONCLUSION

An increased level of health anxiety in men may be advantageous, as it may motivate to self-examination and healthcare seeking when disturbing symptoms arise. Research is needed to investigate whether health anxiety has a protective effect on cancer metastasis at the time of detection, or whether health anxiety increases the risk of over-diagnosis and overtreatment.

Correlates of HPV vaccine uptake in school-based routine vaccination of preadolescent girls in Norway: A register-based study of 90,000 girls and their parents

OBJECTIVE

To assess demographic, socioeconomic and behavioural correlates of HPV vaccination of preadolescent girls in a publicly funded, school-based vaccination programme.

METHODS

Data for all Norwegian girls born 1997-1999, eligible for routine school-based HPV vaccination in 2009-2011 (n=90,842), and their registered mother and father, were merged from national registries. Correlates of girl vaccination status were analysed by unadjusted and multivariable logistic regression.

RESULTS

In total, 78.2% of the girls received the first dose of the HPV vaccine, 74.6% received three doses, and 94.8% received the MMR vaccine. Correlates associated with initiation of HPV vaccination included parental age, income and education, maternal occupational status and cervical screening attendance, and girl receipt of the MMR vaccine. Rates of completion of HPV vaccination among initiators were high, and disparities in completion were negligible. Maternal and paternal correlates of daughter HPV vaccination status were similar.

CONCLUSIONS

Routine school-based vaccination generally provides equitable delivery, yet some disparities exist. Information campaigns designed to reach the sub-groups with relatively low vaccine uptake could reduce disparities. In none of the sub-groups investigated did uptake of the HPV vaccine approach that of the MMR vaccine, further demonstrating a general potential for improvement in HPV vaccine uptake.

Developing National Cancer Registration in Developing Countries - Case Study of the Nigerian National System of Cancer Registries

The epidemiological transition in sub-Saharan Africa (SSA) has given rise to a concomitant increase in the incidence of non-communicable diseases including cancers. Worldwide, cancer registries have been shown to be critical for the determination of cancer burden, conduct of research, and in the planning and implementation of cancer control measures. Cancer registration though vital is often neglected in SSA owing to competing demands for resources for healthcare. We report the implementation of a system for representative nation-wide cancer registration in Nigeria - the Nigerian National System of Cancer Registries (NSCR). The NSCR coordinates the activities of cancer registries in Nigeria, strengthens existing registries, establishes new registries, complies and analyses data, and makes these freely available to researchers and policy makers. We highlight the key challenges encountered in implementing this strategy and how they were overcome. This report serves as a guide for other low- and middle-income countries (LMIC) wishing to expand cancer registration coverage in their countries and highlights the training, mentoring, scientific and logistic support, and advocacy that are crucial to sustaining cancer registration programs in LMIC.

Women treated with breast conserving surgery do better than those with mastectomy independent of detection mode, prognostic and predictive tumor characteristics

BACKGROUND

Primary breast conserving treatment (BCT) is well known to have similar long-term survival as mastectomy in breast cancer patients. However, recent studies are suggesting better survival among women treated with BCT compared with mastectomy. More knowledge is needed to understand how disease specific survival is influenced by detection mode, prognostic and predictive tumor characteristics. We aimed to investigate this issue among women targeted by the Norwegian Breast Cancer Screening Program.

METHOD

Information about 9547 women aged 50-69 years diagnosed with primary invasive breast cancer without distant metastasis, who underwent either BCT or mastectomy, 2005-2011, were included in the study. Kaplan-Meier plots were used to estimate six years survival, while Cox proportional hazards models were used to estimate the hazard ratio (HR) of breast cancer death associated with surgical treatment. Information about molecular subtype, detection mode, age at diagnosis, tumor size, lymph node involvement, and histologic grade, in addition to radiation treatment, chemotherapy and endocrine therapy were included in adjusted analyses.

RESULTS

BCT was performed among 61.9% of the women included in the study. Women treated with BCT had prognostic and predictive favorable tumor characteristics compared to women treated with mastectomy. Adjusted analyses revealed a 1.7 (95% CI: 1.3-2.4) higher risk of breast cancer death among women who underwent mastectomy compared with BCT.

CONCLUSION

Women treated with BCT have significantly better breast cancer-specific survival and a lower risk of dying from breast cancer compared to women treated with mastectomy, independent of detection mode, prognostic and predictive tumor characteristic.

The percentage of lepidic growth is an independent prognostic factor in invasive adenocarcinoma of the lung

Background

The literature is inconclusive as to whether the percentage of the lepidic component of an invasive adenocarcinoma (AC) of the lung influences prognosis. We studied a population-based series of selected, resected invasive pulmonary ACs to determine if incremental increases in the lepidic component were an independent, prognostic variable.

Methods

Patients undergoing resection for lung cancer reported to the Cancer Registry of Norway and diagnosed in the period 1993-2002 with a bronchioloalveolar carcinoma (BAC) (old terminology) (adenocarcinoma in situ, AIS in the new terminology) in the lung were selected. A pulmonary pathologist reviewed all sections and estimated the percentage of the lepidic component. Follow-up of survival was to the end of 2013.

Results

One hundred thirty-one patients were identified, 102 had AC with lepidic growth. Of these, 44 had AC with a component of lepidic growth less than 50 % and seven had AC with 95 % lepidic component or more. One of the latter cases was considered to be AIS. In regression analyses, superior survival was associated with a greater lepidic component (p = 0.041). Mucinous tumors had a worse prognosis than non-mucinous (p = 0.012) in regression analyses, as did increasing age and stage. The five-year observed survival was 69.0 % for non-mucinous cases and 66.7 % for the group with a lepidic component of 80 % or greater.

Conclusion

The percentage of the lepidic component appears to be an independent, significant prognostic factor in a selection of pulmonary AC.

Cancer risk among parous women following assisted reproductive technology

STUDY QUESTION

Do women who give birth after assisted reproductive technology (ART) have an increased risk of cancer compared with women who give birth without ART?

SUMMARY ANSWER

Without correction, the results indicate an increase in overall cancer risk, as well as a 50% increase in risk of CNS cancer for women giving birth after ART, however the results were not significant after correcting for multiple analyses.

WHAT IS KNOWN ALREADY

Studies regarding the effects of hormonal treatments involved with ART on subsequent cancer risk have provided inconsistent results, and it has also been suggested that infertility itself could be a contributory factor.

STUDY DESIGN, SIZE, DURATION

A population-based cohort consisting of all women registered in the Medical Birth Registry of Norway as having given birth between 1 January 1984 and 31 December 2010 was assembled (n = 812 986). Cancers were identified by linkage to the Cancer Registry of Norway. Study subjects were followed from start of first pregnancy during the observational period until the first cancer, death, emigration, or 31 December 2010.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Of the total study population (n = 806 248), 16 525 gave birth to a child following ART. Cox regression analysis computed hazard ratios (HR) and 95% confidence intervals (CI) comparing cancer risk between ART women and non-ART women; for overall cancer, and for cervical, ovarian, uterine, central nervous system (CNS), colorectal and thyroid cancers, and for malignant melanoma.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 22 282 cohort members were diagnosed with cancer, of which 338 were ART women and 21 944 non-ART women. The results showed an elevated risk in one out of seven sites for ART women. The HR for cancer of the CNS was 1.50 (95% CI 1.03- 2.18), and among those specifically subjected to IVF (without ICSI) the HR was 1.83 (95% CI 1.22-2.73). Analysis of risk of overall cancer gave an HR of 1.16 (95% CI 1.04-1.29). Among those who had delivered only one child by the end of follow-up, the HR for ovarian cancer was 2.00 (95% CI 1.08-3.65), and for those nulliparous at entry the HR was 1.80 (95% CI 1.04-3.11). However, all findings became non-significant after correcting for multiple analyses.

LIMITATIONS, REASONS FOR CAUTION

The results of elevated risk of overall cancer and CNS cancer lost significance when adjusting for multiple analyses, implying an important limitation of the study. The follow-up time was relatively short, especially for ART women. In addition, as the cohort was relatively young, there were few incident cancers, especially for some rarer cancer forms, such as uterine cancer. Risk assessments according to different causes of infertility could not be done.

WIDER IMPLICATIONS OF THE FINDINGS

In light of the findings in the present study, further studies should be made on risk of CNS and ovarian cancer, and continued monitoring of all those treated with ART is encouraged. Our findings may only be generalizable to women who give birth after ART, and the risk for women who remain nulliparous after ART remains to be assessed.

STUDY FUNDING/COMPETING INTEREST

The study was funded by the Norwegian National Advisory Unit on Women's Health. All authors claim no competing interests.

Data quality monitoring and performance metrics of a prospective, population-based observational study of maternal and newborn health in low resource settings

BACKGROUND

To describe quantitative data quality monitoring and performance metrics adopted by the Global Network's (GN) Maternal Newborn Health Registry (MNHR), a maternal and perinatal population-based registry (MPPBR) based in low and middle income countries (LMICs).

METHODS

Ongoing prospective, population-based data on all pregnancy outcomes within defined geographical locations participating in the GN have been collected since 2008. Data quality metrics were defined and are implemented at the cluster, site and the central level to ensure data quality. Quantitative performance metrics are described for data collected between 2010 and 2013.

RESULTS

Delivery outcome rates over 95% illustrate that all sites are successful in following patients from pregnancy through delivery. Examples of specific performance metric reports illustrate how both the metrics and reporting process are used to identify cluster-level and site-level quality issues and illustrate how those metrics track over time. Other summary reports (e.g. the increasing proportion of measured birth weight compared to estimated and missing birth weight) illustrate how a site has improved quality over time.

CONCLUSION

High quality MPPBRs such as the MNHR provide key information on pregnancy outcomes to local and international health officials where civil registration systems are lacking. The MNHR has measures in place to monitor data collection procedures and improve the quality of data collected. Sites have increasingly achieved acceptable values of performance metrics over time, indicating improvements in data quality, but the quality control program must continue to evolve to optimize the use of the MNHR to assess the impact of community interventions in research protocols in pregnancy and perinatal health.

TRIAL REGISTRATION NUMBER

NCT01073475.

Prostate cancer, prostate cancer death, and death from other causes, among men with metabolic aberrations

Supplemental Digital Content is available in the text.

Background:

Few previous studies of metabolic aberrations and prostate cancer risk have taken into account the fact that men with metabolic aberrations have an increased risk of death from causes other than prostate cancer. The aim of this study was to calculate, in a real-life scenario, the risk of prostate cancer diagnosis, prostate cancer death, and death from other causes.

Methods:

In the Metabolic Syndrome and Cancer Project, prospective data on body mass index, blood pressure, glucose, cholesterol, and triglycerides were collected from 285,040 men. Risks of prostate cancer diagnosis, prostate cancer death, and death from other causes were calculated by use of competing risk analysis for men with normal (bottom 84%) and high (top 16%) levels of each factor, and a composite score.

Results:

During a mean follow-up period of 12 years, 5,893 men were diagnosed with prostate cancer, 1,013 died of prostate cancer, and 26,328 died of other causes. After 1996, when prostate-specific antigen testing was introduced, men up to age 80 years with normal metabolic levels had 13% risk of prostate cancer, 2% risk of prostate cancer death, and 30% risk of death from other causes, whereas men with metabolic aberrations had corresponding risks of 11%, 2%, and 44%.

Conclusions:

In contrast to recent studies using conventional survival analysis, in a real-world scenario taking risk of competing events into account, men with metabolic aberrations had lower risk of prostate cancer diagnosis, similar risk of prostate cancer death, and substantially higher risk of death from other causes compared with men who had normal metabolic levels.

Comprehensive Analysis of the Incidence and Survival Patterns of Lung Cancer by Histologies, Including Rare Subtypes, in the Era of Molecular Medicine and Targeted Therapy: A Nation-Wide Cancer Registry-Based Study From Taiwan

Lung cancer is the third most common cancer in the world and has the highest cancer mortality rate. A worldwide increasing trend of lung adenocarcinoma has been noted. In addition, the identification of epidermal growth factor receptor (EGFR) mutations and the introduction of EGFR inhibitors to successfully treat EGFR mutated non-small cell lung cancers are breakthroughs for lung cancer treatment. The current study evaluated the incidence and survival of lung cancer using data collected by the Taiwan Cancer Registry between 1996 and 2008. The results showed that the most common histologic subtype of lung cancer was adenocarcinoma, followed by squamous cell carcinoma, small cell carcinoma, large cell carcinoma, neuroendocrine tumors, lymphoma, and sarcoma. Overall, the incidence of lung cancer in Taiwan increased significantly from 1996 to 2008. An increased incidence was observed for adenocarcinoma, particularly for women, with an annual percentage change of 5.9, whereas the incidence of squamous cell carcinoma decreased. Among the subtypes of lung cancer, the most rapid increase occurred in neuroendocrine tumors with an annual percentage change of 15.5. From 1996-1999 to 2005-2008, the 1-year survival of adenocarcinoma increased by 10% for men, whereas the 1-, 3-, and 5-year survivals of adenocarcinoma for women increased by 18%, 11%, and 5%, respectively. Overall, the incidence of lung cancer has been increasing in Taiwan, although the trends were variable by subtype. The introduction of targeted therapies was associated with a significantly improved survival for lung adenocarcinoma in Taiwan; however, more studies are needed to explain the rising incidence of lung adenocarcinoma. In addition, it is important to investigate the molecular pathogenesis of the various subtypes of lung cancer to develop novel therapeutic agents.

Long-term risk of colorectal cancer in individuals with serrated polyps

OBJECTIVE

Although serrated polyps may be precursors of colorectal cancer (CRC), prospective data on the long-term CRC risk in individuals with serrated polyps are lacking.

DESIGN

In a population-based randomised trial, 12,955 individuals aged 50-64 years were screened with flexible sigmoidoscopy, while 78 220 individuals comprised the control arm. We used Cox models to estimate HRs with 95% CIs for CRC among individuals with ≥1 large serrated polyp (≥10 mm in diameter), compared with individuals with adenomas at screening, and to population controls, and multivariate logistic regression to assess polyp risk factors for CRC.

RESULTS

A total of 103 individuals had large serrated polyps, of which 81 were included in the analyses. Non-advanced adenomas were found in 1488 individuals, advanced adenomas in 701. Median follow-up was 10.9 years. Compared with the control arm, the HR for CRC was 2.5 (95% CI 0.8 to 7.8) in individuals with large serrated polyps, 2.0 (95% CI 1.3 to 2.9) in individuals with advanced adenomas and 0.6 (95% CI 0.4 to 1.1) in individuals with non-advanced adenomas. A large serrated polyp was an independent risk factor for CRC, adjusted for histology, size and multiplicity of concomitant adenomas (OR 3.3; 95% CI 1.3 to 8.6). Twenty-three large serrated polyps found at screening were left in situ for a median of 11.0 years. None developed into a malignant tumour.

CONCLUSIONS

Individuals with large serrated polyps have an increased risk of CRC, comparable with individuals with advanced adenomas. However, this risk may not be related to malignant growth of the serrated polyp.

TRIAL REGISTRATION NUMBER

The Norwegian Colorectal Cancer Screening trial is registered at clinicaltrials.gov (NCT00119912).

Joint occurrence of Merkel cell carcinoma and non-Hodgkin lymphomas in four Nordic countries

The objective of this study was to assess the reciprocal association between non-Hodgkin lymphoma (NHL) and Merkel cell carcinoma (MCC) using the data of four Nordic Cancer Registries. Data for this study were drawn from the Danish, Finnish, Norwegian, and Swedish cancer registries. Standardized incidence ratios (SIRs) for MCC among NHL patients, and for NHL among MCC patients, were calculated. There were 109 838 individuals with NHL and 1411 individuals with MCC, of which 28 had joint occurrence of NHL and MCC. In 18 cases, NHL was diagnosed first, and in 10 cases, MCC was diagnosed first. The SIR for MCC after NHL was 4.34 (95% confidence interval 2.57-6.85). The SIR for NHL after MCC was 3.13 (1.50-5.77). Although the absolute frequency of joint occurrence of MCC and NHL is low, individuals suffering from one of the cancer forms have an increased risk of the other.

Hyperemesis gravidarum and risk of cancer in offspring, a Scandinavian registry-based nested case-control study

BACKGROUND

Hyperemesis gravidarum is a serious condition affecting 0.8-2.3% of pregnant women and can be regarded as a restricted period of famine. Research concerning potential long-term consequences of the condition for the offspring, is limited, but lack of nutrition in-utero has been associated with chronic disease in adulthood, including some cancers. There is growing evidence that several forms of cancer may originate during fetal life. We conducted a large study linking the high-quality population-based medical birth- and cancer registries in Norway, Sweden and Denmark, to explore whether hyperemesis is associated with increased cancer risk in offspring.

METHODS

A registry-based nested case-control study. Twelve types of childhood cancer were selected; leukemia, lymphoma, cancer of the central nervous system, testis, bone, ovary, breast, adrenal and thyroid gland, nephroblastoma, hepatoblastoma and retinoblastoma. Conditional logistic regression models were applied to study associations between hyperemesis and risk of childhood cancer, both all types combined and separately. Cancer types with five or more exposed cases were stratified by age at diagnosis. All analysis were adjusted for maternal age, ethnicity and smoking, in addition to the offspring's Apgar score, placental weight and birth weight. Relative risks with 95% confidence intervals were calculated.

RESULTS

In total 14,805 cases and approximately ten controls matched on time, country of birth, sex and year of birth per case (147,709) were identified. None of the cancer types, analyzed combined or separately, revealed significant association with hyperemesis. When stratified according to age at diagnosis, we observed a RR 2.13 for lymphoma among adolescents aged 11-20 years ((95% CI 1.14-3.99), after adjustment for maternal ethnicity and maternal age, RR 2.08 (95% CI 1.11-3.90)). The finding was not apparent when a stricter level of statistical significance was applied.

CONCLUSIONS

The main finding of this paper is that hyperemesis does not seem to increase cancer risk in offspring. The positive association to lymphoma may be by chance and needs confirmation.

Educational attainment among long-term survivors of cancer in childhood and adolescence: a Norwegian population-based cohort study

PURPOSE

The number of young cancer survivors has increased over the past few decades due to improvement in treatment regimens, and understanding of long-term effects among the survivors has become even more important. Educational achievements and choice of educational fields were explored here.

METHODS

Five-year cancer survivors born in Norway during 1965-1985 (diagnosed <19 years) were included in our analysis by linking Norwegian population-based registries. Cox regression was applied to study the educational attainment among survivors of central nervous system (CNS) tumours, those assumed to have received CNS-directed therapy, and other cancer survivors relative to the cancer-free population. Logistic regression was used to compare the choice of educational fields between the cancer survivors at undergraduate and graduate level and the cancer-free population.

RESULTS

Overall, a lower proportion of the cancer survivors completed intermediate (67 vs. 70 %), undergraduate (31 vs. 35 %) and graduate education (7 vs. 9 %) compared with the cancer-free population. Deficits in completion of an educational level were mainly observed among survivors of CNS-tumours and those assumed to have received CNS-directed therapy. Choices of educational fields among cancer survivors were in general similar with the cancer-free population at both undergraduate and graduate levels.

CONCLUSION

Survivors of CNS-tumours and those assumed to have received CNS-directed therapy were at increased risk for educational impairments compared with the cancer-free population. Choices of educational fields were in general similar.

IMPLICATIONS FOR CANCER SURVIVORS

Careful follow-up of the survivors of CNS-tumours and those assumed to have received CNS-directed therapy is important at each level of education.

Benzene exposure and risk of lymphohaematopoietic cancers in 25 000 offshore oil industry workers

BACKGROUND

The aim of this work was to examine the risk of lymphohaematopoietic (LH) cancer according to benzene exposure among offshore workers.

METHODS

Cancer registry data were used to identify 112 cancer cases diagnosed during 1999-2011 in a cohort of 24 917 Norwegian men reporting offshore work between 1965 and 1999. Analyses were conducted according to a stratified case-cohort design with a reference subcohort of 1661 workers. Cox regression was used to estimate hazard ratios with 95% confidence intervals, adjusted for other benzene exposure and smoking.

RESULTS

Most workers were exposed to benzene for <15 years. The upper range values of average intensity and cumulative exposure were estimated to 0.040 p.p.m. and 0.948 p.p.m.-years, respectively. Risks were consistently elevated among exposed workers for all LH cancers combined and for most subgroups, although case numbers were small and yielded imprecise risk estimates. There was evidence of dose-related risk patterns according to cumulative exposure for acute myeloid leukaemia (AML), multiple myeloma (MM) (P trends 0.052 and 0.024, respectively), and suggestively so for chronic lymphocytic leukaemia (CLL) according to average intensity (P trend 0.094).

CONCLUSIONS

Our results support an association between cumulative and intensity metrics of low-level benzene exposure and risk for AML, MM, and suggestively for CLL.

Social inequalities and smoking-associated breast cancer - Results from a prospective cohort study

OBJECTIVE

The association between smoking and breast cancer has been found in most recent, large cohort studies. We wanted to investigate how smoking-associated breast cancer varies by level of education, a well-established measure of socioeconomic status.

METHODS

We included 302,865 women with 7490 breast cancer cases. Participants were assigned to low, moderate or high level of education and analyzed by smoking status (ever/never), and stratified by birth cohorts (≤1950>). We used Cox proportional hazard to estimate hazard ratios (HRs) and confidence intervals (CIs), adjusting for age, number of children, age at first childbirth, BMI, age at enrollment and physical activity.

RESULTS

Women born ≤1950 with low and moderate levels of education had a 40% increase in smoking-associated breast cancer risk (HR=1.40, 95% CI 1.25-1.57 and HR=1.14, 95% CI 1.05-1.24, respectively). Women in the same age group with high level of education did not have an increase in risk. No increased breast cancer risk was found among women born after 1950 for any level of education, when analyzed by smoking status. Longer duration of smoking before first childbirth was consistently associated with increasing risk of breast cancer in all three categories of education (all p for trends<0.01).

CONCLUSION

Smoking for several years before first childbirth increases the risk of breast cancer, regardless of educational level.

Survival is Better After Breast Conserving Therapy than Mastectomy for Early Stage Breast Cancer: A Registry-Based Follow-up Study of Norwegian Women Primary Operated Between 1998 and 2008

Background

Breast-conserving therapy (BCT) and mastectomy (MTX) has been considered to have a similar long-time survival. However, better survival in women undergoing BCT compared with MTX is found in two recent register studies from the United States. The purpose of this study was to compare survival after BCT and MTX for women with early-stage breast cancer in Norway.

Methods

Women with invasive, early-stage breast cancer (1998–2008) where BCT and MTX were considered as equally beneficial treatments were included for a total of 13,015 women. Surgery was divided in two main cohorts (primary BCT, primary MTX) and five subcohorts. Analyses were stratified into T1N0M0, T2N0M0, T1N1M0, T2N1M0, and age groups (<50, 50–69, ≥70). Overall survival and breast cancer-specific survival (BCSS) were calculated in life tables, hazard ratios by Cox regression, and sensitivity analyses.

Results

Five-year BCSS for women who underwent primary BCT or primary MTX was 97 and 88 %, respectively. Women who underwent primary MTX had a hazard ratio of 1.64 (95 % confidence interval 1.43–1.88) for breast cancer death compared with women who underwent primary BCT after adjusting for the year of diagnosis, age at diagnosis, stage, histology, and grade.

Conclusions

Survival was better or equal after breast-conserving therapy than mastectomy in all early stages, surgical subcohorts, and age groups. This advantage could not only be attributed to differences in tumor biology.