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Observations on the Latest Mesothelioma Trends from Recent SEER Data

Gnarus expert Jorge Sirgo reviews the latest annual federal data on mesothelioma diagnoses in the United States became available on April 14, 2017.

Observations on the Latest Mesothelioma Trends from Recent SEER Data

Observations on the Latest Mesothelioma Trends from Recent SEER Data

by Jorge Sirgo

The latest annual federal data on mesothelioma diagnoses in the United States became available on April 14, 2017.  The data reports on rates of mesothelioma diagnoses during 2014, as determined from “cancer registries” from a sampling of some hospitals in the United States.

The data arises from the Surveillance, Epidemiology, and End Results (“SEER”) Program of the National Cancer Institute.  The report is more technically described as the 1973-2014 SEER Research Incidence data (November 2016 submission).  SEER collects data on cancer cases from various locations and sources throughout the United States.  Data collection began in 1973 with a limited amount of registries and continues to expand to include even more areas and demographics today.

The data in 2014 reflect moderate changes from 2013, but appear to support the long-run trends previously identified in the data.

The SEER 9 database (the database with registry information collected since 1973) shows that the overall rate of mesothelioma diagnoses has been falling since the early 1990s.  The rate trend differs, however, by sex.  While the rate of male mesothelioma diagnoses has been falling since the early 1990s, the rate of female mesothelioma diagnoses appears to remain constant.  See the figure below to review the trends:

The rates above are used to extrapolate from the sample to an estimate of the population of mesothelioma diagnoses.  The SEER incidence data are represented below in the following chart:

Overall, the data indicate the estimated number of mesothelioma diagnoses increased from 2,872 in 2013 to 3,255 in 2014.  Estimated male mesothelioma diagnoses increased from 2,213 in 2013 to 2,418 in 2014.  Estimated female mesothelioma diagnoses increased from 659 in 2013 to 837 in 2013.  The data does not distinguish between pleural and peritoneal mesothelioma diagnoses.  The declining trend in rates noted above for overall and male diagnoses can be translated into potentially declining incidence.  However, the relatively constant rate of female mesothelioma diagnoses (combined with increasing population, longevity, etc.) appear to show increasing female incidence of mesothelioma diagnoses.

The decline in the rates and point estimates can be examined further by drilling down to the registry level:

There are four noteworthy increases in the registry-level rate:

  • Detroit increases from 0.74 to 1.14 (+55%)
  • San Francisco – Oakland increases from 0.85 to 1.08 (+27%)
  • Hawaii increases from 0.34 to 0.42 (+22%)
  • Iowa increases from 0.84 to 1.00 (+19%)

The overall SEER 9 rate increases from 0.83 to 0.92 between 2013 to 2014 (+11%).  Excluding the four registries noted above, the overall rate declines from 0.89 to 0.86 between 2013 to 2014 (-3%).  On the surface, it would appear these 4 registries are driving the increase observed in the overall rate.

However, while the increases of the 4 registries noted above are relatively large, the 95% confidence intervals suggest they are not statistically different (remember these are extrapolated estimates).  For example, in Detroit the 2013 estimate of 0.74 has a 95% CI of [0.49, 1.03] and in 2014 the estimate of 1.14 has a 95% CI of [0.85, 1.55].  These intervals overlap suggesting the true rates in these two years are very likely equivalent.

In addition, the greater rates associated with 2014 are not unprecedented.  Looking at their history back through 1973, these values have been present before.

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