Christopher Johnson, MPH, Epidemiologist, Cancer Data Registry of Idaho (NAACCR Board – Representative-At-Large)
Multiple primary cancers are interesting because they can provide insight into the etiologic role of genes, the environment, and prior cancer treatment on a cancer patient’s risk of developing a subsequent cancer. Over time, the burden of multiple primary cancers has increased as patients are living longer following a diagnosis of cancer.
Cancer registries in the U.S. and the most of Canada use SEER multiple primary rules to count incident cases, while cancer registries in other parts of the world use rules from the International Agency for Research on Cancer and International Association of Cancer Registries (IARC/IACR). Compared to SEER rules, IARC/IACR rules are less complex, have not changed over time, and report fewer multiple primary cancers, particularly cancers that occur in paired organs, at the same anatomic site and with the same or related histologic type. Different rules for registering and reporting multiple primary cancers can make data comparisons between the U.S. and other parts of the world difficult.
SEER*Stat now includes a feature whereby cancer incidence data reported using SEER rules can be analyzed to reflect IARC/IACR rules. In a paper just released by Cancer Causes and Control (see below), we evaluated the effect of SEER and IARC/IACR multiple primary rules on cancer incidence rates and trends using data from the SEER Program. We estimated age-standardized incidence rates and trends (1975–2011) for the top 26 cancer categories using joinpoint regression analysis. Incidence rates were higher using SEER compared to IARC/IACR rules for all cancers combined (3%) and, in rank order, melanoma (9%), female breast (7%), urinary bladder (6%), colon (4%), kidney and renal pelvis (4%), oral cavity and pharynx (3%), lung and bronchus (2%), and non-Hodgkin lymphoma (2%). Differences in incidence rates using the two sets of multiple primary rules were larger for older patients. Trends were similar using both sets of multiple primary rules, with the exception of cancers of the urinary bladder and kidney and renal pelvis.
The choice of multiple primary coding rules affects cancer incidence rates and trends. Entities reporting incidence data using SEER multiple primary rules may want to consider also reporting incidence rates and trends using IARC/IACR rules to facilitate international data comparisons.
Read Full Article (The abstract below is from Springer Link)
Abstract
Purpose
An examination of multiple primary cancers can provide insight into the etiologic role of genes, the environment, and prior cancer treatment on a cancer patient’s risk of developing a subsequent cancer. Different rules for registering multiple primary cancers (MP) are used by cancer registries throughout the world making data comparisons difficult.
Methods
We evaluated the effect of SEER and IARC/IACR rules on cancer incidence rates and trends using data from the SEER Program. We estimated age-standardized incidence rate (ASIR) and trends (1975–2011) for the top 26 cancer categories using joinpoint regression analysis.
Results
ASIRs were higher using SEER compared to IARC/IACR rules for all cancers combined (3 %) and, in rank order, melanoma (9 %), female breast (7 %), urinary bladder (6 %), colon (4 %), kidney and renal pelvis (4 %), oral cavity and pharynx (3 %), lung and bronchus (2 %), and non-Hodgkin lymphoma (2 %). ASIR differences were largest for patients aged 65+ years. Trends were similar using both MP rules with the exception of cancers of the urinary bladder, and kidney and renal pelvis.
Conclusions
The choice of multiple primary coding rules effects incidence rates and trends. Compared to SEER MP coding rules, IARC/IACR rules are less complex, have not changed over time, and report fewer multiple primary cancers, particularly cancers that occur in paired organs, at the same anatomic site and with the same or related histologic type. Cancer registries collecting incidence data using SEER rules may want to consider including incidence rates and trends using IARC/IACR rules to facilitate international data comparisons.
The opinions expressed in this article are those of the authors and may not represent the official positions of NAACCR.
