Aspects of progress in cancer in New Zealand: comparisons of survival with Australia, and gene mutations in the management of lung cancer

Abstract

Abstract (Study I) Previous studies have shown substantially higher mortality rates from cancer in New Zealand compared to Australia, but these studies have not included data on patient survival. This study compares the survival of cancer patients diagnosed in 2006-10, and compared with 2000-05, in the whole populations of New Zealand and Australia. Identical period survival methods were used to calculate relative survival ratios for all cancers combined, and for 24 cancers in males and 26 cancers in females, from 1 to 10 years from diagnosis. Cancer survival was lower in New Zealand, with 5-year relative survival being 4.2% lower in women, and 3.8% lower in men for all cancers combined during 2006-10. Significantly lower relative survival ratios in New Zealand were seen in 15 out of 24 cancer sites for men, and 17 out of 26 for women, including bowel, lung, female breast, and prostate cancers, at some or all time points. Only two cancers, chronic lymphocytic leukaemia in men and acute myeloid leukaemia for women showed significantly higher survival in New Zealand. For most cancers, the differences in survival were maximum at 1 year after diagnosis, becoming smaller later; however, for breast cancer, the survival difference increased with time after diagnosis. The lower survival in New Zealand, and the higher mortality rates shown earlier, suggest that further improvements in recognition, diagnosis, and treatment of cancer in New Zealand should be possible. As the survival differences are seen soon after diagnosis, attention needs to be given particularly to aspects of early diagnosis in New Zealand. Abstract (Study II) Previous studies found that presence of Epidermal Growth Factor Receptor (EGFR) gene mutations in patients with Non-Small Cell Lung Cancer (NSCLC) is strongly associated with clinical response to Tyrosine Kinase Inhibitors (TKIs). Treating with TKI requires confirmation of EGFR gene mutation by testing. To assist in determining the strategy for routine EGFR gene mutation testing, linked data, sourced from New Zealand Cancer Registry and LabPLUS laboratory, was used to study EGFR gene mutation testing and prevalence in a populationbased cohort of NSCLC patients in northern region of New Zealand between 1st August, 2012 and 30th April, 2014. Of total 748 patients included in this study, 429 (57%, 95% CI 54 to 61%) were tested for EGFR gene mutation, with higher testing rates in females, younger age groups, Southeast Asians, those with metastasis, and those being registered at later time during the study period. Among 414 patients tested having valid results, 86 patients (21%, 95% CI 17 to 25%) were reported as EGFR gene mutation detected. EGFR mutations were found more commonly in females, Southeast Asians, and non-smokers. Of 85 EGFR mutation-positive patients with TKI therapy information, 60 patients (71%, 95% CI 60 to 79%) were given treatment with TKI, either gefitinib or erlotinib or both. Younger patients and those with distant metastasis of the disease were more likely to be given TKI therapy. EGFR gene mutation testing occurred selectively in New Zealand patients, indicating the need to promote involvement of disadvantaged populations. EGFR gene mutation-positive lung cancer is prevalent in New Zealand, with significant variations regarding gender, ethnicity, and smoking status. It provides background information for future research and decision making in EGFR gene mutation testing. Differences in access to TKI drug treatment among mutationpositive patients, being influenced by age and extent of disease, imply that clinical decision may also be relevant.