Cancer in the Shannon region – how we compare nationally
I have been asked on a number of occasions if there is a possibility that Shannon and the surrounding region has a higher incidence of cancer relative to the rest of the country. So in February, I asked the general question of Dr Harry Cromber, Director of the national cancer registry and within the overall picture I also asked him to look specifically at breast cancer. His office have now come back to me with their findings.
Attached please find results of the analysis of cancer incidence in the Shannon-Town area as you requested (attached in both word and excel format: "cancer data"). As Dr. Comber has indicated we can only provide statistics to the level of electoral division (ED). Shannon-Town lies within the ED "Clenagh" (see attached map "SHANNON AREAS ED'S").
So we looked at incidence rates in Clenagh and compared them to rates in the wider Mid-Western Health Board overall as well as to Ireland overall. To be sure that all residents of the area are included, I repeated the analysis to include the electoral district "Drumline" also as its border with Clenagh is fairly close to Shannon town. The results are shown in 2 tables in the attached file. Basically the analysis for Clenagh alone and for the wider area (Clenagh and Drumline combined) shows that the number of cancer cases found in the area was slightly higher than what would be expected based on known incidence rates for the region or the entire country overall but this was not statistically significant. Overall in Clenagh alone, incidences of all cancers were 3% higher than the national average. As the analysis consists of basically comparing incidence rates in local areas with average overall reference rates, it is normal and expected that some areas will have higher incidences than the reference and other areas will have lower incidences. The 95% confidence intervals are generated to give us an idea of how reliable these results are - ie how much the results show a true pattern and are not just a random chance finding. In this case the 95% confidence intervals are wide and show that the results are not statistically significant.
As you mentioned female breast cancer specifically in your email, I generated figures for this cancer specifically (table 2 in the attached "cancer data" file). Results here show that although slightly more cases were diagnosed that what would have been expected, this also was not statistically significant. Looking at the range of cancers diagnosed in Clenagh and the wider area overall and the age profile of patients diagnosed there - the results are very similar to the national picture - in other words, nothing unusual appears when looking at the age distribution of cancer patients in the Shannon-Town area or the type of cancers diagnosed there compared with the country overall.
There are some notes in the attached file (below the tables) that explain elements in the tables in a bit more detail and I have also attached a document on cancer clusters that we normally provide with this type of analysis - it provides a bit more information on the limitations of local area analysis and some points to bear in mind when looking at the results. I hope that the attached information is useful to you. If you have any queries on the data or anything in the results or need any further information, please feel free to contact me.
Best regards, Sandra Deady PhD,
Data analyst, National Cancer Registry
This is the link to the statistics CLICK HERE
This is the link to a general document on cancer and how it should be looked at in a local context CLICK HERE
Regards
Tony
