# Urban Rural Differences in Breast Cancer in New Zealand
## 3 Results  
There were 12,372 women on the two registers with a diagnosis of invasive breast cancer. 2364 were classified as rural, living in an independent rural centre or a rural community, and 9885 were classified as urban (in 123 women domicile was not classified). When comparing the characteristics of urban and rural women with breast cancer, rural women tended to be older and were more likely to be Maori (Table 1). Stage of disease at diagnosis was similar and tumour size was also similar with 51.7% of rural women having a tumour size less than 20 mm and 50.3% of urban women (\(p\) = 0.238). When we stratified by ethnicity, we find that rural Maori tended to be older, more likely to be diagnosed with metastatic breast cancer (\(p\) < 0.01) and less likely to be screen detected than urban Maori (Table 2). Rural NZ European were older and less likely to be diagnosed with Grade 3 cancer, \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{2}{c}{**Characteristics**} & \multicolumn{2}{c}{**Rural**} & \multicolumn{2}{c}{**Urban**} & \multicolumn{2}{c}{**Total**} & \multicolumn{2}{c}{\(p\)**-Value (Chi-Square Test)**} \\ \hline \multicolumn{5}{c}{**Age Groups**} & \multicolumn{5}{c}{**<0.001**} \\ \(<\)40 & 126 & 5.3\% & 669 & 6.8\% & 795 & 6.5\% & \\
40–49 & 401 & 17.0\% & 2263 & 22.9\% & 2664 & 21.7\% & \\
50–59 & 626 & 26.5\% & 2689 & 27.2\% & 3315 & 27.1\% & \\
60–69 & 600 & 25.4\% & 2233 & 22.6\% & 2833 & 23.1\% & \\
70–79 & 364 & 15.4\% & 1178 & 11.9\% & 1542 & 12.6\% & \\
80+ & 247 & 10.4\% & 853 & 8.6\% & 1100 & 9.0\% & \\ \hline \multicolumn{5}{c}{**Cancer Stage**} & \multicolumn{5}{c}{**0.066**} \\ I & 997 & 42.2\% & 4291 & 43.4\% & 5288 & 43.2\% & \\ II & 890 & 37.6\% & 3643 & 36.9\% & 4533 & 37.0\% & \\ III & 345 & 14.6\% & 1514 & 15.3\% & 1859 & 15.2\% & \\ IV & 132 & 5.6\% & 437 & 4.4\% & 569 & 4.6\% & \\ \hline \multicolumn{5}{c}{**Grade**} & \multicolumn{5}{c}{**<0.001**} \\
1 & 557 & 25.3\% & 2270 & 24.1\% & 2827 & 24.4\% & \\
2 & 1113 & 50.5\% & 4281 & 45.5\% & 5394 & 46.5\% & \\
3 & 535 & 24.3\% & 2850 & 30.3\% & 3385 & 29.2\% & \\ Unknown & 159 & & 484 & & 643 & \\ \hline \multicolumn{5}{c}{**Tumour Size (mm)**} & \multicolumn{5}{c}{**0.238**} \\
0-20 & 1123 & 51.7\% & 4726 & 50.3\% & 5849 & 50.5\% & \\
20+ & 1050 & 48.3\% & 4674 & 49.7\% & 5724 & 49.5\% & \\ Unknown & 191 & & 485 & & 676 & \\ \hline \multicolumn{5}{c}{**Mode of Detection**} & \multicolumn{5}{c}{**0.909**} \\ Not screen detected & 1458 & 61.7\% & 6084 & 61.5\% & 7542 & 61.6\% & \\ Screen detected & 906 & 38.3\% & 3801 & 38.5\% & 4707 & 38.4\% & \\ \hline \multicolumn{5}{c}{**EPR**} & \multicolumn{5}{c}{**0.034**} \\ ER and PR negative & 395 & 17.1\% & 1840 & 19.0\% & 2235 & 18.7\% & \\ ER and/or PR positive & 1910 & 82.9\% & 7819 & 81.0\% & 9729 & 81.3\% & \\ Unknown & 59 & & 226 & & 285 & \\ \hline \multicolumn{5}{c}{**Ethnicity**} & \multicolumn{5}{c}{**<0.001**} \\ NZ European & 1932 & 82.2\% & 6943 & 71.2\% & 8875 & 73.3\% & \\ Maori & 311 & 13.2\% & 844 & 8.7\% & 1155 & 9.5\% & \\ Pacific & 38 & 1.6\% & 759 & 7.8\% & 797 & 6.6\% & \\ Asian & 47 & 2.0\% & 920 & 9.4\% & 967 & 8.0\% & \\ Others & 22 & 0.9\% & 285 & 2.9\% & 307 & 2.5\% & \\ Unknown & 14 & & 134 & & 148 & \\ \hline
**Total** & 2364 & 100\% & 9885 & 100\% & 12,249 & 100\% & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Characteristics of urban and rural women. but otherwise they had similar characteristics to urban NZ European including similar screen detected rates and similar stage at diagnosis. When comparing 5-year and 10-year survival for urban versus rural women, we found that breast cancer survival is very similar for urban and rural women overall, but that for Maori women survival appears to be worse for rural compared with urban women (Table 3). Rural Maori women had inferior breast cancer-specific survival at 10 years at 72.1% compared to 77.9% for urban Maori (\(p\) = 0.072). The 5-year and 10-year all-cause survival was 71.6% and 55.8% for rural Maori women compared to 77.9% and 64.9% for urban Maori women (\(p\) = 0.017).