Characteristics of lung cancers and accuracy and completeness of registration in the New Zealand Cancer Registry.

AIMS: This study aims to report the characteristics of newly diagnosed lung cancer cases, and to examine the data accuracy of registrations in the New Zealand Cancer Registry (NZCR) in 2011-2015.

METHODS: The accuracy and completeness of lung cancer registrations in the NZCR was explored using the Midland Lung Cancer Register (MLCR, including Lakes, Waikato, Tairawhiti and Bay of Plenty District Health Boards) and clinical records. A combined Midland Lung Cancer Dataset was created based on the NZCR and the MLCR. The characteristics of lung cancer cases was described and compared between Māori and non-Māori patients. The subgroup differences were examined by Chi-Square tests. The odds ratio of having small cell lung cancer compared to non-small cell lung cancer between Māori patients and non-Māori patients was estimated using the logistic regression model.

RESULTS: The combined Midland Lung Cancer Dataset included 2,057 verified lung cancer registrations, including 656 (31.9%) Māori patients and 1,401 (68.1%) non-Māori patients. Māori patients were more likely to be diagnosed at a younger age, more likely to be female, more likely to be a current or ex-smoker and more likely to have small cell lung cancer than non-Māori. The difference of cancer stage at diagnosis between Māori and others was not significant. After adjustment, the odds ratio of having small cell lung cancer for Māori patients compared to non-Māori patients was 1.55 (95% CI: 1.17-2.05). The adjusted odds ratio of having small cell lung cancer was 4.06 (95% CI: 1.72-9.60) for current smokers and 2.68 (95% CI: 1.14-6.30) for ex-smokers compared to patients who never smoked.

CONCLUSIONS: Combining the two sources of data gives a more complete picture of the incidence and tumour characteristics of lung cancer in our region. Our dataset suggests that Māori patients are more likely to have small cell lung cancer than non-Māori patients.