Welsh Cancer Intelligence and Surveillance Unit Uned Gwybodaeth a Gwyliadwriaeth Canser Cymru

Transcription

1 Cancer in Wales Incidence by stage at diagnosis 2011 to Latest available cancer incidence by stage at diagnosis official statistics for Wales for diagnosis years 2011 to 2015, by cancer type, age, sex, area deprivation, Wales and England, health board and local authority of residence Responsible statistician Rebecca Thomas Telephone Things you should know Introduction Melanoma and cancers of the uterus and breast have the highest proportion of early stage at diagnosis, whereas cancers of the lung, stomach, pancreas and liver have the lowest Trends in proportions of prostate and lung cancer early stage at diagnosis increased whilst unknown stage decreased There has been little change in breast cancer early stage at diagnosis and for all stages of bowel cancer 1 Cancer in Wales - Incidence by stage at diagnosis,

2 Older people tend to have higher proportions of unknown stage at diagnosis for most cancer types The proportion of people in each stage at diagnosis does not vary according to area deprivation for breast, prostate, bowel and lung cancer Trends in the proportion of lung cancer diagnoses at stage 1 increased across areas of all deprivation levels, and was largest in least deprived areas Lung cancer stage at diagnosis was similar in Wales and England apart from a higher level of stage 4 in England, and a higher level of unknown stage in Wales There is no significant variation between health boards in the proportion of stage 1 breast cancer at diagnosis Abertawe Bro Morgannwg University Health Board has the lowest proportion of people diagnosed with stage 1 lung cancer, less than half that in Cwm Taf 2 Cancer in Wales - Incidence by stage at diagnosis,

3 Things you should know First ever publication This statistical release is the first publication of its kind for Wales a national resident population-based profile of cancer incidence by the stage at diagnosis using cancer registry data. Stage at diagnosis refers to the size of a cancer and how far it has spread from where it originated at the time of diagnosis. Stage is summarised in cancer registries from 1 to 4; stage 1 indicates that the cancer is small and has not spread anywhere whereas stage 4 indicates the cancer has spread to at least one other body organ. Stage 1 and stage 2 usually refer to early stage. Stage 3 and stage 4 are referred to late stage at diagnosis. Unknown stage Cases of cancer recorded on the cancer registry may have an unknown stage for many reasons. Firstly, not all types of cancers can be staged (a minority). Out of stageable cancer sites then the stage at diagnosis may be unknown for some of the following reasons: Cancer registration system limitations Insufficient clinical data received to be able to derive cancer registry stage Exchange of data on cancer patients living in Wales but diagnosed or treated in England often did not include staging data until recently Patients might be too ill or turn down diagnostic tests to allow clinical staging The completeness of staging data captured by the Welsh Cancer Intelligence and Surveillance Unit has continued to improve beyond Further information about cancer registry data completeness and quality can be found here Registration processes have changed over the period with a new IT system which now includes more clinical data from hospitals in Wales, as well as England, and in addition to pathology data. Cancer teams in hospitals have also improved the reporting of stage. This is important because a high proportion of unknown stage at diagnosis can cause difficulties with interpretation of statistics along with difficulties comparing over time and between cancers. Statistical significance If a difference in the proportions of stage between populations is statistically significant, it means that difference is unlikely to have occurred due to chance alone, and that we can be more confident that we are observing a true difference. In this commentary we use the conventional arbitrary cut-off of less than 5% chance to mean statistically significant. Just because a difference is statistically significant doesn t necessarily mean that it is large or important that can depend on our judgement and other things. 3 Cancer in Wales - Incidence by stage at diagnosis,

4 Multiple testing has not been taken into account and so 1 in 20 tests will be statistically significant by chance alone. Breast cancer refers to female breast cancer only. Melanoma refers to melanoma of the skin only (i.e. not retina, for example). Some cancers cannot be staged using TNM (e.g. brain cancers) and some site specific staging classifications have not been captured at WCISU during this period (e.g. haematological cancers) and are not included in this report. Further information about the definitions can be found at 4 Cancer in Wales - Incidence by stage at diagnosis,

5 Introduction Early stage at diagnosis tends to be associated with an improved survival rate if there can be timely and equitable access to effective treatments. The key policy context for improving cancer control in Wales is the Welsh Government s refreshed Cancer Delivery Plan The Cancer Delivery Plan highlights how international studies have shown that Wales and other UK studies have historically had lower cancer survival than many other high income countries. One major contributor, amongst other factors, highlighted by some of these studies appears to be a tendency towards later stage at diagnosis. This first ever statistical release on national population-based cancer incidence by stage at diagnosis in Wales will directly inform the work of and provide a baseline for the NHS Wales Cancer Implementation Group s Detecting Cancer Early programme. 5 Cancer in Wales - Incidence by stage at diagnosis,

6 Melanoma and cancers of the uterus and breast have the highest proportion of early stage at diagnosis, whereas cancers of the lung, stomach, pancreas and liver have the lowest Figure 1: Proportion (%) of early and late stage at diagnosis for common cancer types for people resident in Wales, diagnosed in 2015 Early (1 and 2) stage Late (3 and 4) stage Unknown stage Melanoma Uterus Female breast Bladder Prostate Kidney Colon Bowel (Colorectal) Rectum Ovary Head & neck Oesophagus Lung Stomach Pancreas Liver Source: 's National Cancer Registry The distribution of stage at diagnosis varies considerably depending on the type of cancer. For many types early stage at diagnosis predominates, for example melanoma, uterus and breast. Bowel (colorectal) cancer has almost half of cases presenting at a late stage. Others, such as pancreas, stomach and lung cancer have predominantly late stages at diagnosis. Although liver cancer has the lowest proportion of early stage at diagnosis, it does not have the corresponding expected highest level of recorded late stage at diagnosis. This is almost certainly due to the high proportion of recorded stage as unknown. There are likely to be several reasons for this, described at the beginning of this commentary. The main reason is likely to be that most patients are late stage and may be too ill to have many staging tests or biopsies. 6 Cancer in Wales - Incidence by stage at diagnosis,

7 Trends in proportions of prostate and lung cancer early stage at diagnosis increased whilst unknown stage decreased There has been little change in breast cancer early stage at diagnosis and for all stages of bowel cancer Figure 2: Trends in proportion (%) of each stage at diagnosis for the commonest cancers from 2011 to 2015 Source: 's National Cancer Registry Here we describe the trends in the distribution of stage at diagnosis from 2011 to 2015 for the four commonest cancers in Wales. Although for breast cancer there was a small reduction in the proportion of stage 3 cases at diagnosis, this may have been in part due to an increase in the proportion of unknown stage. There was no significant change in the proportions of early stages (1 and 2), but the increase in unknown stage makes this hard to interpret. It is not yet clear why the proportion of unknown stage recorded in the cancer registry has increased. There was a large increase in the proportion of stage 2 prostate cancer cases, with smaller increases in the other stages, but with a large decrease in the 7 Cancer in Wales - Incidence by stage at diagnosis,

8 proportion of unknown stage cases. One main reason for the observed trends may be the redistribution of unknown stage to other known stages with improved stage reporting from cancer multi-disciplinary teams in hospitals. There was no significant change to the distribution of stage at diagnosis for bowel (colorectal) cancer between 2011 and The proportions of both stages 1 and 2 lung cancer increased between 2011 and The proportion of stage 1 cases almost doubled from 8.4% to 15.8%. At the same time, there was a significant decrease for unknown stage at diagnosis category. This may reflect in part a true stage shift of earlier lung cancer diagnosis in Wales as well as some redistribution from the unknown category. However, any changes due to decreasing the proportion of unknown stage would have probably only significantly increased later stages of diagnosis. 8 Cancer in Wales - Incidence by stage at diagnosis,

9 Older people tend to have higher proportions of unknown stage at diagnosis for most cancer types In 2015, there was a higher proportion of unknown stage at diagnosis for the older age group compared to the younger age group for most cancer types, apart from liver cancer. Women aged 75 years and over diagnosed with breast cancer had a significantly higher proportion of unknown stage at diagnosis (41.0%), compared to the two younger age groups (0-64 and years). The proportion of stage 1 breast cancer at diagnosis in women aged 75 years and over was also significantly lower (18.2%) than the younger age groups. Women with the highest proportion were aged years (44.6%). In all three age groups (0-64, 65-74, 75+ years), the proportion of men diagnosed with stage 1 prostate cancer was small, being smallest in the oldest age group (1.1%). Only a third of the oldest men were diagnosed with stage 2 disease, compared with over a half of men in the younger age groups. The proportion of men with prostate cancer of unknown stage at diagnosis was also the highest in the oldest men (33.5%). People diagnosed with bowel (colorectal) cancer aged 75 and over had a higher proportion with an unknown stage (21.8%) and a lower proportion with stage 1 disease (10.8%), than younger age groups. Younger people (0-64 years) with bowel (colorectal) cancer had a lower proportion with stage 2 at diagnosis (15.4%), along with a higher proportion of stage 4 disease (21.9%), compared to older age groups. The lower proportion of unknown cases may partly account for this finding. The 75 and over age group had a considerably higher proportion of unknown stage at diagnosis (19.4%) for lung cancer than each of the younger age groups. This is slightly offset by a higher proportion of stage 4 cases in the 0-64 year old age group. 9 Cancer in Wales - Incidence by stage at diagnosis,

10 The proportion of people in each stage at diagnosis does not vary according to area deprivation for the most common cancers (breast, prostate, bowel and lung cancer) Trends in the proportion of lung cancer diagnoses at stage 1 increased across areas of all deprivation levels, and was largest in least deprived areas Figure 3: Trends in stage at diagnosis (%) by area deprivation (quintiles) for female breast cancer in Wales, Source: 's National Cancer Registry In 2015, there was no significant difference in the proportion of female breast cancer cases in each stage at diagnosis between people living in areas of Wales with different levels of deprivation. The observed increase in the overall proportion of breast cancer cases of unknown stage is apparent for women who live in areas of all levels of deprivation. However, this increase is only statistically significant for the least, and next least deprived areas. In the least deprived areas, this change was associated with a small but significant decrease in the proportion of stage 3 cases. 10 Cancer in Wales - Incidence by stage at diagnosis,

11 Figure 4: Trends in stage at diagnosis (%) by area deprivation (quintiles) for prostate cancer in Wales, Source: 's National Cancer Registry In 2015, there was no significant difference in the proportion of prostate cancer cases in each stage at diagnosis between people living in areas of Wales with different levels of deprivation. The proportion of prostate cancer cases of unknown stage at diagnosis has decreased in areas of all levels of deprivation. This more than halved in the areas of most deprivation and those with the next least deprivation level. But it decreased by over two-thirds in men from the least deprived areas of Wales, where prostate cancer is more common. At the same time, the decrease in unknown stage proportions has possibly led to an increase in the proportions of late stage disease across areas of all levels of deprivation (significant increases of stage 4 disease in areas of middle to least deprivation, and stage 3 in middle deprived areas). But there were also large and statistically significant increases in the proportions of stage 2 prostate cancer across all levels of area deprivation. Finally, there was a small but statistically significant increase in the proportion of stage 1 prostate cancer only in the least deprived areas between 2011 and Cancer in Wales - Incidence by stage at diagnosis,

12 Figure 5: Trends in stage at diagnosis (%) by area deprivation (quintiles) for bowel (colorectal) cancer in Wales, Source: 's National Cancer Registry There has been no significant change to the distribution of stage at diagnosis for bowel cancer for all the levels of area disadvantage over the latest five year period. Figure 6: Trends in stage at diagnosis (%) by area deprivation (quintile) for lung cancer in Wales, Source: 's National Cancer Registry 12 Cancer in Wales - Incidence by stage at diagnosis,

13 There has been a large decrease in the proportion of unknown stage at diagnosis for people diagnosed with lung cancer across areas with all levels of deprivation. But during the same period there has not been a significant corresponding increase in the proportion of late stage disease for any level of deprivation. There has been an improvement for early stage disease across all areas, with increases in proportions of stage 2 lung cancer cases, and significant increases in stage 1 at diagnosis. Lung cancer is considerably more common in more deprived areas, and the increase in the proportion of stage 1 cases was the largest (10.0 percentage points) in people from the least deprived areas. 13 Cancer in Wales - Incidence by stage at diagnosis,

14 Lung cancer stage at diagnosis was similar in Wales and England apart from a higher level of stage 4 in England, and a higher level of unknown stage in Wales Figure 7: Stage at diagnosis (%) for breast cancer in Wales and England, 2015 Wales England stage stage stage stage unknown stage Source Wales: 's National Cancer Registry Source England: Although there is a wide gap between the proportion of female breast cancer cases at an early stage at diagnosis between Wales and England, the extent of unknown stage at diagnosis for female breast cancer in the cancer registry in Wales in 2015 makes meaningful comparison and interpretation difficult. 14 Cancer in Wales - Incidence by stage at diagnosis,

15 Figure 8: Stage at diagnosis (%) for bowel (colorectal) cancer in Wales and England, 2015 Wales England stage stage stage stage unknown stage Source Wales: 's National Cancer Registry Source England: Although in Wales there is a slightly higher proportion of stage 3 bowel cancer cases than England, there is a moderately higher proportion of later stage 4 disease in England. However, once more, comparison and interpretation is made difficult by the degree of unknown stage at diagnosis cases in 2015 in Wales. 15 Cancer in Wales - Incidence by stage at diagnosis,

16 Figure 9: Stage at diagnosis (%) for lung cancer in Wales and England, 2015 Wales England stage stage stage stage unknown stage Source Wales: 's National Cancer Registry Source England: The proportion of lung cancer cases at each stage at diagnosis was similar in Wales and England, apart from stage 4. This latest stage had almost seven percentage points more cases than in Wales. But, again, comparison and interpretation is made difficult by the proportion of unknown stage at diagnosis cases in the registry in Wales being higher than in England but only a seven percentage point difference. 16 Cancer in Wales - Incidence by stage at diagnosis,

17 There is no significant variation between health boards in the proportion of stage 1 breast cancer at diagnosis Abertawe Bro Morgannwg University Health Board has the lowest proportion of people diagnosed with stage 1 lung cancer, less than half that in Cwm Taf Figure 10: Proportion (%) of female breast cancer cases with each stage at diagnosis, by health board of residence, 2015, ranked by stage 1 proportion stage 1 stage 2 stage 3 stage 4 unknown stage Wales Aneurin Bevan UHB Hywel Dda UHB Cwm Taf UHB Betsi Cadwalader UHB Abertawe Bro Morgannwg UHB Cardiff and Vale UHB Powys THB Source: 's National Cancer Registry There is no significant variation between health boards in the proportion of stage 1 breast cancer at diagnosis. However, there is a significantly lower proportion of stage 2 cases in Betsi Cadwaladr compared to Wales as a whole. It is unclear whether this may be related to its relatively high proportion of unknown cases, which, in turn, may be related to historic cross-border data issues. Women diagnosed with breast cancer in the Aneurin Bevan area have a particularly low proportion of unknown stage cases. This may account for its relatively high but non-significant proportion of stage 3 cases. 17 Cancer in Wales - Incidence by stage at diagnosis,

18 Figure 11: Proportion (%) of bowel (colorectal) cancer cases with each stage at diagnosis, by health board of residence, 2015, ranked by stage 1 proportion stage 1 stage 2 stage 3 stage 4 unknown stage Wales Cardiff and Vale UHB Cwm Taf UHB Betsi Cadwalader UHB Aneurin Bevan UHB Abertawe Bro Morgannwg UHB Powys THB Hywel Dda UHB Source: 's National Cancer Registry Whilst there is variation in the proportion of unknown stage bowel cancer cases, no health board was statistically different to Wales as a whole. For late stage bowel cancer, no health board had a proportion of stage 4 disease different to Wales as a whole, but the proportion of stage 3 cases was significantly lower than Wales for Cardiff and Vale residents. 18 Cancer in Wales - Incidence by stage at diagnosis,

19 Figure 12: Proportion (%) of lung cancer cases with each stage at diagnosis, by health board of residence, 2015, ranked by stage 1 proportion stage 1 stage 2 stage 3 stage 4 unknown stage Wales Cwm Taf UHB Cardiff and Vale UHB Betsi Cadwalader UHB Powys THB Hywel Dda UHB Aneurin Bevan UHB Abertawe Bro Morgannwg UHB Source: 's National Cancer Registry The majority of people diagnosed with lung cancer presented at a late stage of disease in all Welsh health board areas, but there is still variation. Abertawe Bro Morgannwg residents had a proportion of unknown stage at diagnosis for lung cancer significantly higher than Wales as a whole. The reasons for this are unclear. Cardiff and Vale University Heath Board residents had the lowest proportion (statistically significant) of lung cancer unknown stage at diagnosis. Cwm Taf University Health Board stands out as having an unknown stage proportion similar to Wales as a whole, with a relatively small proportion of people with the latest stage 4 disease, along with the highest proportion with stage 1 lung cancer at diagnosis. Abertawe Bro Morgannwg University Health Board has the lowest proportion of people diagnosed at the earliest stage 1, less than half the proportion in Cwm Taf Public Health Wales NHS Trust. Material contained in the data provided to you may be reproduced under the terms of the Open Government Licence (OGL) provided it is done so accurately and is not used in a misleading context. Acknowledgement to Public Health Wales NHS Trust / WCISU to be clearly stated. 19 Cancer in Wales - Incidence by stage at diagnosis,