Abstract
Abstract
Background In the 1990s outcomes in Danish lung cancer patients were poor compared with the other Nordic countries. The five-year survival was only about 5%, only 10% of patients were operated on and less than 60% received active surgical or oncologic treatment. This paper describes trends in mortality and survival of lung cancer in Denmark from 2000 to 2012.
Methods The study population comprised 52 435 patients with a diagnosis of cancer of the trachea and the lung, primarily ascertained from the Danish Lung Cancer Register and grouped into three cohorts by year of diagnosis. The outcome measures covered the first year as well as the first full five-year period after diagnosis and comprised absolute mortality rate (per 100 patient years), absolute survival, and the relative survival. All outcomes were estimated for the overall patient population as well as after stratification by covariates.
Results Overall, the mortality rates have declined significantly over time from 117 per 100 patient years to 88 for the one-year mortality and from 75 to 65 for the five-year mortality rates, respectively. With the exception of patients with advanced stage, declining mortality was observed for all strata by gender, comorbidity, stage and surgery status and was accompanied by corresponding improvements in both absolute and relative survival.
Conclusions The mortality has been significantly declining and the prognosis correspondingly improving in lung cancer in Denmark since the turn of the millennium. As of today, survival after lung cancer in Denmark is probably in line with the international standard. Based on our results we recommend introducing mortality indicators based on all-cause mortality within the patient population in international benchmarking studies as comparisons based on cancer-specific mortality relative to the total general population may be misleading when interpreted in the context of outcomes and quality of care.
In the 1990s outcomes in Danish lung cancer patients did not compare with the other Nordic countries. The five-year survival was only about 5%, only 10% of patients were operated on and less than 60% received active surgical or oncologic treatment [1,2].
With this background the Danish Lung Cancer Group (DLCG) was formed. As its first task DLCG gathered an overview of the management of lung cancer in Denmark, showing that about 90 departments in Denmark undertook the diagnostic investigation of lung cancer using very different and often outdated methods. Similarly, treatment was scattered and different [3].
Subsequently, the group adopted a dual strategy: to establish Danish guidelines, and to ensure continuous monitoring of the extent to which departments followed these guidelines and the results obtained. The first version of “The guideline for diagnosis and treatment of lung cancer in Denmark” was released in 1998 and the Danish Lung Cancer Registry (DLCR) was established and online in 2000 as a platform for monitoring interventions and outcomes [4].
This paper describes trends in mortality and survival of lung cancer in Denmark from 2000 to 2012 to be discussed and compared with other reports.
Material and methods
Setting and source population
Annually 3500–4500 new cases of lung cancer are registered in Denmark. Half of the patients have at the time of diagnosis significant comorbidities [5] and only about 30% of the patients are in a clinical stage suitable for treatment with curative intention, and approximately 20% do not receive any active surgical or oncological treatment at all [6].
The number of departments involved with the diagnostic evaluation in lung cancer has decreased to 13 in 2013, all of which use similar diagnostic setup. Positron emission tomography-computed tomography (PET-CT) scans, endoscopic ultrasound and advanced pathology examinations are used regardless of geography. The diagnostic setup for lung cancer in Denmark is currently believed to be at the highest international standard and in accordance with international guidelines [7,8].
Approximately 85% of the new cases represent non-small cell lung cancer. About 20% of these patients currently receive surgical treatment and 10% undergo radiotherapy treatment with curative intention. The proportion of patient offered palliative treatment has in the same period also increased [9].
Data sources
Data in this report is based on patients with a diagnosis of lung cancer from 1 January 2000 to 31 December 2012. In DLCR the date of diagnosis is defined as the date of starting the diagnostic evaluation. The patients included in DLCR are ascertained based on coded information in the National Patient Register [ICD10 code C33 and C34 (cancer of the trachea and the lung)]. Supplementary information for each patient is obtained from the National Pathology Register as well as from the clinical units. The completeness of DLCR since 2003 is approximately 98% [9].
During the period 2000–2002 the data completeness in DLCR was relatively poor (<70%) [9]. As a consequence, the Danish Cancer Registry (CR) has been used as supplementary patient ascertainment source for the period 1 January 2000 to 31 December 2002.
DLCR and CR have similar high coverage and use similar algorithms to ascertain cases from registrations contained in the National Patient Register. However, DLCR is used as the primary data source, as the ascertainment of lung cancer in DLCR is believed to be of higher quality as clinicians validate and supplement data.
Survival status was obtained for all patients from the Danish Civil Registration Service which assures that none are lost to follow-up.
Covariates
In addition to age and sex, the following covariates were included in the analyses. Staging of the disease at diagnosis [Union for International Cancer Control (UICC)-based clinical Tumor, Node and Metastases (TNM) staging as well as presence or absence of metastases]; Charlson Comorbidity Index [10] (CCI, grouped by CCI = 0, CCI = 1, CCI = 2 and CCI ≥3, derived from primary discharge diagnoses registered the National Patient Register for each of the patients in the period from 10 years before and up to 90 days before the date of lung cancer diagnosis) [5] and yes/no to elective resection of the lung tumor.
Statistical methods
Patient cohorts were established by year of diagnosis (2000–2004; 2005–2009; 2010–2012). Patients were followed from diagnosis until death or end of follow-up (23 May 2014).
The outcome measures comprised: 1) absolute all-cause mortality rate (per 100 patient years), defined as the number of deaths regardless of cause divided by the sum of the patient time at risk of death over the follow-up period concerned; 2) absolute survival, defined as the proportion of patients surviving to the end of the follow-up period concerned; and 3) relative survival, defined as the ratio of absolute survival divided by the expected survival. The outcome measures were estimated for the first year after diagnosis as well as for the full five-year period after diagnosis, respectively. For the latter estimates only patients with the potential of follow-up for the full five-year period of diagnosis were included, thus excluding the period 2010–2012.
Estimates were obtained overall as well as with stratification by the covariates mentioned above. In all analyzes, standardization by age was performed by adjusting each cohort for males and females separately to an age structure in accordance with the International Cancer Survival Standard (ICSS) cancer population weights (cluster 1) [11]. Confidence intervals (95% level) were estimated based on the approximated Poisson distribution. χ2 statistics were used to assess heterogeneity across the diagnosis cohorts.
Results
Overall, 52 435 patients with first-time diagnosis of C33 and C34 (cancer of the trachea and the lung) were registered from 1 January 2000 to 31 December 2012 (Table 1).
Table 1. Distribution of lung cancer by diagnosis cohort and age group, gender, comorbidity level, cancer stage and surgery.
Comorbidity, using the Charlson Index, increased over time, with a drop in proportion of patients without comorbidity from 59% in the first five-year cohort to 45% in the last cohort from 2010 to 2012.
Disease stage has been operationalized according to presence versus absence of metastatic disease at diagnosis, as well as by the more detailed TNM UICC stage. The importance of using both classifications is reflected in the proportion of patients with unknown stage. This proportion is relatively low and with a downward trend using the crude method, whereas in the TNM classification the proportion with unknown stage is greater in the first cohort, however, steeply decreasing to a level comparable to that seen with the crude classification method. Resection rate is the proportion of the total lung cancer population undergoing intended curative surgery, and it is seen to increase from 12.1% to 16.3%.
Over time the incident cases has increased in number and age and exhibited a shift from predominance of men towards gender balance, higher levels of comorbidity and no major shift in stages.
Absolute all-cause mortality rate per 100 person years
Both the short- and long-term age-adjusted absolute mortality rate declined statistically significantly over time for men and for women as well as overall, with a slightly stronger decline in women than in men (Table 2). A similar decline has been observed for each of the four categories of comorbidity. For patients without comorbidity the short-term mortality rate has declined 23% and even higher for patients with comorbidity.
Table 2. One- and five-year absolute, age-adjusted mortality rate per 100 patient years. Overall estimates and stratified by gender, comorbidity level, cancer stage, and priority of surgery.
In patients with metastatic disease the mortality rate were almost four-fold higher as compared to patients without metastases. For the non-metastatic disease the short-term mortality rate has been reduced from 82 for the period 2000–2004 to 41 for the period 2010–2012 and the long-term mortality rate from 53 for the period 2000–2004 to 37 for the period 2005–2009. In patients with metastatic disease a minor improvement has also been observed. A similar pattern has been found with stratification for TNM stages. The reduction in mortality rate has been particularly pronounced in patients with stage I with a reduction in the short-term mortality from 39 in the period 2000–2004 to 13 in the period 2010–2012.
In patients undergoing resection the short-term mortality rate has significantly declined over time, from 28 for the first cohort to 11 for the latest cohort. The short-term mortality rate for the patients not undergoing resection has also been declining, but more slowly and at a much higher level, from 136 to 113 for the first and the latest cohort, respectively.
Absolute and relative survival
Table 3 shows the absolute age-adjusted one- and five-year survival proportions, total as well as stratified by gender, comorbidity, stage and resection status. A general pattern of improved one- and five-year survival has been observed, reflecting the decline observed in the all-cause mortality (Table 2). However, for patients with high stage no improvement in survival has been observed. Comparative survival plots for the three diagnostic cohorts are presented in Figure 1, supporting the improving prognosis. Table 4 shows the corresponding relative age-adjusted one- and five-year survival ratios where adjustment has been made for expected mortality in the general Danish population. The general pattern of results is similar to that seen for the absolute survival proportions.
Published online:
08 April 2016![]({"type":"image","src":"/na101/home/literatum/publisher/tandf/journals/content/ionc20/2016/ionc20.v055.sup02/0284186x.2016.1150608/20180731/images/medium/ionc_a_1150608_f0001_c.jpg"})
Figure 1. Survival proportions of observed cohorts.
Table 3. One- and five-year absolute, age-adjusted absolute survival proportion for lung cancer. Overall estimates and stratified by gender, comorbidity level, cancer stage, and priority of surgery.
Table 4. One- and five-year relative, age-adjusted relative survival ratio for lung cancer. Overall estimates and stratified by gender, comorbidity level, cancer stage, and priority of surgery.
Discussion
This report presents population-based data using nationwide health registers with high data completeness (>98%). Only cases with diagnosis based solely on death certificates are excluded by definition. The results clearly demonstrate a declining mortality and a corresponding increase in survival in patients diagnosed from 2000 to 2012. Previous reports have indicated that there has been an inferior Danish survival in lung cancer, but the five-year survival in Denmark is now approaching 15% (Figure 1), which probably is in line with international standards [6,12].
We find that the improvements are most pronounced in patients in low TNM stage without metastatic disease. These findings are partly explained by better quality of the diagnostic setup [4] and are as such an expression of stage migration, but as we observe improvements in the overall survival as well, additional explanations must be considered.
An increasing number of patients receive surgical treatment. Also, more patients receive oncological treatment [9]. Both factors contribute to the observed improvements in survival. Surgical treatment and curatively intended oncological treatment both improve short- and long-term survival and palliative oncological treatment prolong short-term survival [13], which substantiates our findings concerning differences in the short- and long-term survivals.
The evidence of improved prognosis in Danish lung cancer patients, as demonstrated in our findings, contrasts with results presented in international benchmarking where Denmark in general is ranked low compared to most other European countries. The OECD publication from 2013, “Cancer care – assuring quality for better survival” [14], reports that Denmark has the highest mortality rate of lung cancer per 100 000 of inhabitants in the OECD area. The Eurocare-4 [15] as well as the recently updated Eurocare-5 [12] report and “The International Cancer Benchmarking Partnership” [16] publication, based on cancer register data, found low survival in Denmark compared with other societies. The cooperation between the Nordic cancer registers in NORDCAN has found age-standardized relative survival in lung cancer corresponding to all of these publications [17]. However, all of these publications use the standard epidemiological method of calculating lung cancer mortality in relation to the entire population.
An additional explanation behind the difference may be that our study comprises cases diagnosed during the period from 2000 until 2012, thus including more recent observations than the above publications where only data up to 2008 is included. However, when comparing results in cancer treatment two important factors must be considered, i.e. the quality and comparability of the included source data and the methods of estimating used for computing the mortality and survival rates.
In this paper the results are based solely on the lung cancer population and are reported as the absolute age-adjusted mortality rate in the patient population, the absolute age-adjusted survival proportion and the relative age-adjusted survival ratio and their trends over time in the lung cancer population. By calculating the mortality in this way the size of the population of lung cancer patients who are at risk of dying is taken into account.
Using mortality in the patient population as indicator differs from the standard approach in international benchmarking. Here, the cause-specific mortality is calculated as the number of deaths attributable to lung cancer patients compared to the entire population size, thereby ignoring that the number of deaths in the lung cancer population may change as a consequence of changes in the size of the patient population. The incidence level of lung cancer in Denmark is high and rather stable when the demographic changes in the general population are taken into account [6]. However, there are marked gender differences with increasing risk for women and diminishing risk for men, while prognosis of lung cancer is better for women than for men yet at the same time improving for both sexes as seen in Table II. Overall, this means that the prevalence of lung cancer is increasing rapidly, especially for women and consequently, the absolute number of deaths in the population attributable to lung cancer is increasing in spite of the significant improvements in the prognosis for the individual patient. By ignoring these complex epidemiological aspects other reports may fail to detect the improved outcomes in Danish lung cancer treatment.
The two different methods of calculating mortality are illustrated in Figure 2, with estimates standardized according to the ICSS population as described above. The mortality rate in the lung cancer population is decreasing, overall as well as for the sexes separately. The internationally used method, based on the absolute number of deaths in the population attributable to lung cancer as obtained from NORDCAN [18], gives a different picture especially for women, and thereby also totally.
Published online:
08 April 2016Figure 2. Comparison of cancer-specific mortality per 100 000 in the overall population and mortality in the patient population per 100 patient years.
![]({"type":"image","src":"/na101/home/literatum/publisher/tandf/journals/content/ionc20/2016/ionc20.v055.sup02/0284186x.2016.1150608/20180731/images/medium/ionc_a_1150608_f0002_c.jpg"})
Figure 2. Comparison of cancer-specific mortality per 100 000 in the overall population and mortality in the patient population per 100 patient years.
To which extent the differences between data sources used for survival analysis and the analytic methods used may influence the reported benchmarking results are discussed with increasing frequency [19]. In a recent systematical review by Erridge et al. it was pointed out that only comprehensive registers should be included. In addition the registers should include all cases of lung cancer – not only histologically verified or patients reported from hospitals, and that one cannot conclude that the reported patients are representative of those not reported [20].
The data quality and in particular the completeness of ascertainment, even for patients with advanced disease, is very high in the Danish cancer registration and presumably higher compared to the Nordic and European registers. This may account, at least partly, for some of the discrepancy between results from Denmark and otherwise comparable nations in benchmarking studies. Thus, the apparent large Danish mortality in the first year after diagnosis as noted in the benchmarking report [16] may very well be due to incompatible data and selection bias, and this can also be the reason for the observed imbalance in TNM distribution noted in the benchmarking report.
Any remaining difference in results may be attributed to a higher Danish prevalence of comorbidity. Comorbidity is important for the survival and affects the treatment results negatively, but whether differences in comorbidity rates exits between countries are not known at present [5]. Even though there is no evidence that differences in delay of treatment may impact the results in Denmark or other countries, some studies have suggested that there may be significant delay in the Danish primary detection of lung cancer, with the consequence that Danish patients have higher stages of disease at diagnosis [21].
Conclusion
The mortality rate for patients with lung cancer in Denmark has declined significantly since the turn of the millennium, both for men and women. In this paper the results are reported as the absolute age-adjusted mortality rate in the patient population, the absolute age-adjusted survival proportion and the relative age-adjusted survival ratio and their trends over time in the lung cancer population.
This picture is in contrast to results from international benchmarking reports in which indicators of lung cancer mortality is based on lung cancer deaths relative to the total general population. As the results based on this approach are misleading when interpreted in the context of outcome and quality of care, we recommend introducing mortality indicators based on mortality experiences within the patient population in international benchmarking.
| Total period N (%) | Cohort by year of lung cancer diagnosis N (%) | |||
|---|---|---|---|---|
| 2000–2012 | 2000–2004 | 2005–2009 | 2010–2012 | |
| Total | 52435 (100) | 18805 (100) | 20038 (100) | 13592 (100) |
| Age group | ||||
| <45 years | 853 (1.6) | 375 (2.0) | 321 (1.6) | 157 (1.2) |
| 45–54 years | 4336 (8.3) | 1778 (9.5) | 1618 (8.1) | 940 (6.9) |
| 55–64 years | 12807 (24.4) | 4502 (23.9) | 5223 (26.1) | 3082 (22.7) |
| 65–74 years | 18927 (36.1) | 6918 (36.8) | 6975 (34.8) | 5034 (37.0) |
| ≥75 years | 15512 (29.6) | 5232 (27.8) | 5901 (29.4) | 4379 (32.2) |
| Gender | ||||
| Men | 28146 (53.7) | 10505 (55.9) | 10620 (53.0) | 7021 (51.7) |
| Women | 24289 (46.3) | 8300 (44.1) | 9418 (47.0) | 6571 (48.3) |
| Comorbidity level | ||||
| CCI = 0 (None) | 27238 (51.9) | 11113 (59.1) | 10057 (50.2) | 6068 (44.6) |
| CCI = 1 (Low) | 11435 (21.8) | 3795 (20.2) | 4566 (22.8) | 3074 (22.6) |
| CCI = 2 (Medium) | 10027 (19.1) | 2935 (15.6) | 3955 (19.7) | 3137 (23.1) |
| CCI ≥3 (High) | 3735 (7.1) | 962 (5.1) | 1460 (7.3) | 1313 (9.7) |
| Cancer stage | ||||
| Non-metastatic M0 | 23188 (44.2) | 8940 (47.5) | 8321 (41.5) | 5927 (43.6) |
| Metastatic M1 | 22037 (42.0) | 6832 (36.3) | 8820 (44.0) | 6385 (47.0) |
| Unknown Mx | 7210 (13.8) | 3033 (16.1) | 2897 (14.5) | 1280 (9.4) |
| UICC cancer stage | ||||
| I | 6955 (13.3) | 2259 (12.0) | 2746 (13.7) | 1950 (14.3) |
| II | 2715 (5.2) | 741 (3.9) | 946 (4.7) | 1028 (7.6) |
| III | 9816 (18.7) | 3075 (16.4) | 4021 (20.1) | 2720 (20.0) |
| IV | 19508 (37.2) | 4303 (22.9) | 8820 (44.0) | 6385 (47.0) |
| Unknown | 13441 (25.6) | 8427 (44.8) | 3505 (17.5) | 1509 (11.1) |
| Priority of surgery | ||||
| Elective | 7429 (14.2) | 2271 (12.1) | 2942 (14.7) | 2216 (16.3) |
| No surgery | 45006 (85.8) | 16534 (87.9) | 17096 (85.3) | 11376 (83.7) |
CCI, Charlson Comorbidity Index.
| Total period | Calendar period of lung cancer diagnosis | |||||
|---|---|---|---|---|---|---|
| Absolute mortality | 2000–2012 | 2000–2004 | 2005–2009 | 2010–2012 | p-Value | |
| All | 0–1 year | 103 (102–104) | 117 (115–119) | 102 (100–103) | 88 (86–90) | 0.0000 |
| 0–5 year | 70 (69–70) | 75 (74–77) | 65 (64–66) | – | 0.0000 | |
| Gender | ||||||
| Men | 0–1 year | 111 (109–113) | 124 (121–127) | 109 (106–112) | 98 (95–101) | 0.0000 |
| 0–5 year | 76 (74–77) | 81 (79–83) | 71 (69–72) | – | 0.0000 | |
| Women | 0–1 year | 95 (94–97) | 111 (108–114) | 95 (92–97) | 80 (77–82) | 0.0000 |
| 0–5 year | 64 (63–65) | 71 (69–72) | 59 (58–61) | – | 0.0000 | |
| Comorbidity level | ||||||
| CCI = 0 (None) | 0–1 year | 97 (96–99) | 108 (106–111) | 95 (93–97) | 83 (80–86) | 0.0000 |
| 0–5 year | 66 (65–67) | 70 (69–72) | 61 (60–62) | – | 0.0000 | |
| CCI = 1 (Low) | 0–1 year | 107 (104–109) | 129 (124–134) | 105 (101–109) | 88 (84–93) | 0.0000 |
| 0–5 year | 71 (69–72) | 82 (79–85) | 64 (62–66) | – | 0.0000 | |
| CCI = 2 (Medium) | 0–1 year | 109 (106–112) | 128 (123–134) | 111 (107–115) | 88 (84–92) | 0.0000 |
| 0–5 year | 74 (72–76) | 79 (76–82) | 70 (68–73) | – | 0.0000 | |
| CCI ≥3 (High) | 0–1 year | 136 (130–141) | 172 (160–185) | 133 (125–141) | 114 (107–122) | 0.0000 |
| 0–5 year | 101 (96–105) | 117 (110–125) | 90 (85–95) | – | 0.0000 | |
| Cancer stage | ||||||
| Non-metastatic M0 | 0–1 year | 60 (59–62) | 82 (80–85) | 55 (53–57) | 41 (39–42) | 0.0000 |
| 0–5 year | 44 (44–45) | 53 (52–54) | 37 (36–38) | – | 0.0000 | |
| Metastatic M1 | 0–1 year | 168 (166–171) | 188 (183–193) | 165 (161–169) | 157 (153–162) | 0.0000 |
| 0–5 year | 144 (142–147) | 155 (151–159) | 137 (133–140) | – | 0.0000 | |
| Unknown Mx | 0–1 year | 112 (109–115) | 110 (105–115) | 117 (111–122) | 111 (103–119) | 0.0124 |
| 0–5 year | 68 (66–69) | 66 (63–68) | 71 (68–74) | – | 0.0003 | |
| UICC cancer stage | ||||||
| I | 0–1 year | 26 (24–27) | 39 (36–42) | 25 (23–27) | 13 (12–15) | 0.0000 |
| 0–5 year | 22 (21–23) | 27 (26–29) | 18 (17–19) | – | 0.0000 | |
| II | 0–1 year | 48 (45–51) | 69 (62–77) | 47 (42–52) | 35 (32–40) | 0.0000 |
| 0–5 year | 40 (38–43) | 53 (49–58) | 32 (30–35) | – | 0.0000 | |
| III | 0–1 year | 80 (78–82) | 94 (89–98) | 81 (78–85) | 67 (63–70) | 0.0000 |
| 0–5 year | 69 (67–71) | 72 (70–75) | 66 (64–69) | – | 0.0001 | |
| IV | 0–1 year | 160 (158–163) | 160 (154–165) | 165 (161–169) | 157 (153–162) | 0.2291 |
| 0–5 year | 134 (132–137) | 131 (127–135) | 137 (133–140) | – | 0.2289 | |
| Unknown | 0–1 year | 130 (128–132) | 146 (141–152) | 108 (105–111) | 99 (96–102) | 0.0000 |
| 0–5 year | 83 (82–85) | 92 (89–94) | 67 (65–69) | – | 0.0000 | |
| Priority of surgery | ||||||
| Elective | 0–1 year | 18 (17–19) | 28 (26–30) | 17 (16–19) | 11 (10–12) | 0.0000 |
| 0–5 year | 17 (17–18) | 20 (19–21) | 15 (15–16) | – | 0.0000 | |
| No surgery | 0–1 year | 126 (124–127) | 136 (134–139) | 125 (123–128) | 113 (111–116) | 0.0000 |
| 0–5 year | 96 (95–97) | 99 (97–100) | 94 (92–95) | – | 0.0000 | |
CCI, Charlson Comorbidity Index.
| Total period | Calendar period of lung cancer diagnosis | |||||
|---|---|---|---|---|---|---|
| Absolute survival proportion | 2000–2012 | 2000–2004 | 2005–2009 | 2010–2012 | p-Value | |
| All | 0–1 year | 0.38 (0.37–0.38) | 0.33 (0.32–0.34) | 0.38 (0.37–0.39) | 0.43 (0.42–0.44) | 0.0000 |
| 0–5 year | 0.11 (0.11–0.11) | 0.10 (0.09–0.10) | 0.12 (0.11–0.13) | – | 0.0000 | |
| Gender | ||||||
| Men | 0–1 year | 0.35 (0.34–0.35) | 0.31 (0.30–0.33) | 0.35 (0.34–0.36) | 0.39 (0.38–0.41) | 0.0000 |
| 0–5 year | 0.10 (0.09–0.10) | 0.09 (0.08–0.10) | 0.10 (0.10–0.11) | – | 0.0000 | |
| Women | 0–1 year | 0.40 (0.40–0.41) | 0.35 (0.34–0.36) | 0.40 (0.39–0.42) | 0.47 (0.45–0.49) | 0.0000 |
| 0–5 year | 0.12 (0.12–0.13) | 0.11 (0.10–0.12) | 0.14 (0.13–0.14) | – | 0.0000 | |
| Comorbidity level | ||||||
| CCI = 0 (None) | 0–1 year | 0.39 (0.38–0.40) | 0.36 (0.34–0.37) | 0.40 (0.39–0.41) | 0.44 (0.43–0.46) | 0.0000 |
| 0–5 year | 0.12 (0.11–0.12) | 0.11 (0.10–0.12) | 0.13 (0.12–0.14) | – | 0.0000 | |
| CCI = 1 (Low) | 0–1 year | 0.37 (0.36–0.38) | 0.31 (0.29–0.33) | 0.38 (0.36–0.40) | 0.44 (0.42–0.47) | 0.0000 |
| 0–5 year | 0.11 (0.11–0.12) | 0.09 (0.08–0.10) | 0.13 (0.12–0.14) | – | 0.0000 | |
| CCI = 2 (Medium) | 0–1 year | 0.36 (0.35–0.37) | 0.31 (0.29–0.33) | 0.35 (0.34–0.37) | 0.44 (0.42–0.46) | 0.0000 |
| 0–5 year | 0.10 (0.10–0.11) | 0.10 (0.09–0.11) | 0.11 (0.10–0.12) | – | 0.0000 | |
| CCI ≥3 (High) | 0–1 year | 0.31 (0.29–0.33) | 0.24 (0.21–0.27) | 0.31 (0.29–0.34) | 0.38 (0.35–0.42) | 0.0000 |
| 0–5 year | 0.07 (0.06–0.09) | 0.06 (0.05–0.08) | 0.08 (0.07–0.10) | – | 0.0098 | |
| Cancer stage | ||||||
| Non-metastatic M0 | 0–1 year | 0.55 (0.54–0.56) | 0.45 (0.43–0.46) | 0.57 (0.56–0.59) | 0.67 (0.65–0.69) | 0.0000 |
| 0–5 year | 0.19 (0.18–0.20) | 0.16 (0.15–0.16) | 0.23 (0.22–0.24) | – | 0.0000 | |
| Metastatic M1 | 0–1 year | 0.20 (0.20–0.21) | 0.17 (0.16–0.18) | 0.21 (0.20–0.22) | 0.22 (0.21–0.24) | 0.0000 |
| 0–5 year | 0.02 (0.02–0.03) | 0.02 (0.02–0.03) | 0.03 (0.02–0.03) | – | 0.1263 | |
| Unknown Mx | 0–1 year | 0.36 (0.35–0.38) | 0.37 (0.35–0.39) | 0.35 (0.33–0.38) | 0.39 (0.35–0.42) | 0.0670 |
| 0–5 year | 0.12 (0.11–0.13) | 0.12 (0.11–0.13) | 0.11 (0.10–0.12) | – | 0.0604 | |
| UICC cancer stage | ||||||
| I | 0–1 year | 0.77 (0.75–0.80) | 0.68 (0.65–0.71) | 0.78 (0.75–0.82) | 0.88 (0.84–0.92) | 0.0000 |
| 0–5 year | 0.38 (0.36–0.39) | 0.31 (0.29–0.33) | 0.43 (0.41–0.46) | – | 0.0000 | |
| II | 0–1 year | 0.62 (0.59–0.65) | 0.51 (0.46–0.56) | 0.63 (0.58–0.68) | 0.70 (0.65–0.76) | 0.0000 |
| 0–5 year | 0.21 (0.19–0.24) | 0.15 (0.12–0.18) | 0.27 (0.24–0.31) | – | 0.0000 | |
| III | 0–1 year | 0.44 (0.43–0.46) | 0.39 (0.37–0.41) | 0.44 (0.42–0.46) | 0.51 (0.48–0.54) | 0.0000 |
| 0–5 year | 0.09 (0.08–0.10) | 0.09 (0.08–0.10) | 0.09 (0.08–0.10) | – | 0.4673 | |
| IV | 0–1 year | 0.22 (0.21–0.22) | 0.22 (0.20–0.23) | 0.21 (0.20–0.22) | 0.22 (0.21–0.24) | 0.6957 |
| 0–5 year | 0.03 (0.02–0.03) | 0.03 (0.02–0.03) | 0.03 (0.02–0.03) | – | 0.6986 | |
| Unknown | 0–1 year | 0.31 (0.30–0.32) | 0.27 (0.25–0.28) | 0.37 (0.36–0.39) | 0.42 (0.40–0.44) | 0.0000 |
| 0–5 year | 0.09 (0.09–0.10) | 0.08 (0.07–0.09) | 0.12 (0.11–0.13) | – | 0.0000 | |
| Priority of surgery | ||||||
| Elective | 0–1 year | 0.84 (0.82–0.86) | 0.76 (0.73–0.80) | 0.84 (0.81–0.88) | 0.90 (0.86–0.94) | 0.0000 |
| 0–5 year | 0.44 (0.42–0.46) | 0.42 (0.39–0.44) | 0.48 (0.46–0.51) | – | 0.0000 | |
| No surgery | 0–1 year | 0.30 (0.30–0.31) | 0.28 (0.27–0.28) | 0.30 (0.29–0.31) | 0.34 (0.33–0.35) | 0.0000 |
| 0–5 year | 0.06 (0.05–0.06) | 0.06 (0.05–0.06) | 0.06 (0.05–0.06) | – | 0.6563 | |
CCI, Charlson Comorbidity Index.
| Total period | Calendar period of lung cancer diagnosis | |||||
|---|---|---|---|---|---|---|
| Absolute relative survival ratio (95% CI) | 2000–2012 | 2000–2004 | 2005–2009 | 2010–2012 | p-Value | |
| All | 0–1 year | 0.39 (0.38–0.39) | 0.34 (0.34–0.35) | 0.39 (0.38–0.40) | 0.44 (0.43–0.45) | 0.0000 |
| 0–5 year | 0.13 (0.13–0.14) | 0.12 (0.12–0.13) | 0.15 (0.14–0.15) | – | 0.0000 | |
| Gender | ||||||
| Men | 0–1 year | 0.36 (0.35–0.37) | 0.33 (0.32–0.34) | 0.37 (0.35–0.38) | 0.40 (0.39–0.42) | 0.0000 |
| 0–5 year | 0.12 (0.12–0.13) | 0.11 (0.11–0.12) | 0.13 (0.12–0.14) | – | 0.0001 | |
| Women | 0–1 year | 0.41 (0.41–0.42) | 0.36 (0.35–0.38) | 0.42 (0.40–0.43) | 0.48 (0.46–0.50) | 0.0000 |
| 0–5 year | 0.14 (0.14–0.15) | 0.13 (0.12–0.14) | 0.16 (0.15–0.17) | – | 0.0000 | |
| Comorbidity level | – | |||||
| CCI = 0 (None) | 0–1 year | 0.40 (0.40–0.41) | 0.37 (0.36–0.38) | 0.41 (0.40–0.42) | 0.46 (0.44–0.47) | 0.0000 |
| 0–5 year | 0.15 (0.14–0.15) | 0.13 (0.13–0.14) | 0.16 (0.15–0.17) | – | 0.0000 | |
| CCI = 1 (Low) | 0–1 year | 0.38 (0.37–0.39) | 0.32 (0.30–0.34) | 0.39 (0.37–0.41) | 0.45 (0.43–0.48) | 0.0000 |
| 0–5 year | 0.14 (0.13–0.15) | 0.11 (0.10–0.13) | 0.16 (0.15–0.17) | – | 0.0000 | |
| CCI = 2 (Medium) | 0–1 year | 0.37 (0.36–0.39) | 0.32 (0.30–0.35) | 0.37 (0.35–0.39) | 0.45 (0.43–0.48) | 0.0000 |
| 0–5 year | 0.13 (0.12–0.14) | 0.13 (0.11–0.14) | 0.13 (0.12–0.14) | – | 0.0001 | |
| CCI ≥3 (High) | 0–1 year | 0.32 (0.30–0.34) | 0.25 (0.22–0.28) | 0.32 (0.30–0.36) | 0.39 (0.36–0.43) | 0.0000 |
| 0–5 year | 0.09 (0.08–0.11) | 0.08 (0.06–0.10) | 0.10 (0.08–0.12) | – | 0.0095 | |
| Cancer stage | ||||||
| Non-metastatic M0 | 0–1 year | 0.57 (0.56–0.58) | 0.46 (0.45–0.48) | 0.59 (0.58–0.61) | 0.69 (0.66–0.71) | 0.0000 |
| 0–5 year | 0.23 (0.22–0.24) | 0.19 (0.18–0.20) | 0.28 (0.26–0.29) | – | 0.0000 | |
| Metastatic M1 | 0–1 year | 0.21 (0.20–0.21) | 0.18 (0.17–0.19) | 0.22 (0.21–0.23) | 0.23 (0.22–0.24) | 0.0000 |
| 0–5 year | 0.03 (0.03–0.03) | 0.03 (0.02–0.03) | 0.03 (0.03–0.04) | – | 0.1430 | |
| Unknown Mx | 0–1 year | 0.38 (0.36–0.39) | 0.38 (0.36–0.41) | 0.37 (0.34–0.39) | 0.40 (0.37–0.44) | 0.0652 |
| 0–5 year | 0.14 (0.13–0.15) | 0.15 (0.14–0.17) | 0.14 (0.12–0.15) | – | 0.0637 | |
| UICC cancer stage | ||||||
| I | 0–1 year | 0.80 (0.78–0.82) | 0.70 (0.67–0.74) | 0.81 (0.77–0.84) | 0.90 (0.86–0.95) | 0.0000 |
| 0–5 year | 0.46 (0.44–0.48) | 0.38 (0.35–0.41) | 0.52 (0.49–0.56) | – | 0.0000 | |
| II | 0–1 year | 0.64 (0.61–0.67) | 0.52 (0.47–0.58) | 0.65 (0.59–0.70) | 0.73 (0.67–0.78) | 0.0000 |
| 0–5 year | 0.26 (0.23–0.29) | 0.18 (0.15–0.22) | 0.33 (0.29–0.38) | – | 0.0000 | |
| III | 0–1 year | 0.46 (0.44–0.47) | 0.40 (0.38–0.43) | 0.45 (0.43–0.47) | 0.53 (0.50–0.55) | 0.0000 |
| 0–5 year | 0.11 (0.10–0.12) | 0.11 (0.10–0.12) | 0.11 (0.10–0.12) | – | 0.5213 | |
| IV | 0–1 year | 0.22 (0.22–0.23) | 0.22 (0.21–0.24) | 0.22 (0.21–0.23) | 0.23 (0.22–0.24) | 0.6819 |
| 0–5 year | 0.03 (0.03–0.03) | 0.04 (0.03–0.04) | 0.03 (0.03–0.04) | – | 0.6947 | |
| Unknown | 0–1 year | 0.32 (0.31–0.33) | 0.28 (0.26–0.29) | 0.39 (0.37–0.40) | 0.43 (0.42–0.45) | 0.0000 |
| 0–5 year | 0.11 (0.11–0.12) | 0.10 (0.09–0.11) | 0.14 (0.13–0.15) | – | 0.0000 | |
| Priority of surgery | ||||||
| Elective | 0–1 year | 0.86 (0.84–0.89) | 0.79 (0.75–0.82) | 0.87 (0.83–0.90) | 0.92 (0.88–0.96) | 0.0000 |
| 0–5 year | 0.53 (0.51–0.56) | 0.50 (0.47–0.53) | 0.58 (0.55–0.61) | – | 0.0000 | |
| No surgery | 0–1 year | 0.31 (0.31–0.32) | 0.29 (0.28–0.30) | 0.31 (0.30–0.32) | 0.35 (0.34–0.36) | 0.0000 |
| 0–5 year | 0.07 (0.07–0.07) | 0.07 (0.07–0.08) | 0.07 (0.06–0.07) | – | 0.8923 | |
CCI, Charlson Comorbidity Index.
Acknowledgments
This study was funded by the Danish Clinical Quality Improvement Program (Regionernes Kliniske Kvalitetsudviklingsprogram, RKKP). The authors declare no conflicts of interests.
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