New Zealand Prostate Cancer Prevalence
Fact Check: Lifetime risk for prostate cancer in NZ men is 1 in 5
Movember | MEL Data Team
2025-09-24
Summary
The quoted figure from the Australian context: “1 in 5 men will be diagnosed with prostate cancer in their lifetime” likely substantially overestimates current lifetime risk in NZ.
The Prostate Cancer Foundation NZ and the NZ Cancer Society consistently report lifetime risk for New Zealand men at approximately 12.5%, equivalent to approximately 1 in 8 men.
# Create summary table of lifetime risk comparison
comparison_table <- lifetime_risk_comparison %>%
mutate(
`Lifetime Risk (%)` = risk_pct,
`Equivalent Ratio` = risk_ratio,
) %>%
select(Claim = claim, `Lifetime Risk (%)`, `Equivalent Ratio`)
kable(comparison_table,
caption = "Table 1: Lifetime risk of prostate cancer diagnosis") %>%
kable_styling(bootstrap_options = c("striped", "hover", "condensed"),
full_width = FALSE) %>%
row_spec(which(comparison_table$Claim == "NZ Stat"), bold = TRUE, background = "#E3F2FD")| Claim | Lifetime Risk (%) | Equivalent Ratio |
|---|---|---|
| Original Claim (AU) | 20.0 | 1 in 5 |
| NZ Stat | 12.5 | 1 in 8 |
Historical trends in prostate cancer incidence
This section presents long-term trends in prostate cancer incidence in New Zealand, showing both the absolute number of cases and age-standardised rates over time.
# Create annual incidence count plot
count_plot <- ggplot(prostate_count_data, aes(x = year, y = cases)) +
geom_line(linewidth = 1.2, color = "#2E86C1") +
geom_point(size = 3, color = "#2E86C1") +
geom_smooth(method = "loess", se = TRUE, color = "grey", alpha = 0.2) +
labs(title = "Annual Prostate Cancer Point Incidence",
subtitle = "New Zealand Men, 2009-2022",
x = "Year",
y = "Number of new cases") +
scale_x_continuous(breaks = seq(2009, 2022, 2)) +
scale_y_continuous(labels = comma_format()) +
theme_minimal() +
theme(
plot.title = element_text(size = 12, face = "bold"),
plot.subtitle = element_text(size = 10),
axis.text.x = element_text(angle = 45, hjust = 1)
)
# Create ASR plot
asr_plot <- ggplot(prostate_asr_data, aes(x = year, y = asr)) +
geom_line(linewidth = 1.2, color = "#8E44AD") +
geom_point(size = 3, color = "#8E44AD") +
geom_smooth(method = "loess", se = TRUE, color = "grey", alpha = 0.2) +
labs(title = "Age-Standardised Incidence Rate",
subtitle = "New Zealand Men, 2009-2022",
x = "Year",
y = "ASR per 100,000 men") +
scale_x_continuous(breaks = seq(2009, 2022, 2)) +
theme_minimal() +
theme(
plot.title = element_text(size = 12, face = "bold"),
plot.subtitle = element_text(size = 10),
axis.text.x = element_text(angle = 45, hjust = 1)
)
# Combine plots
combined_trends <- count_plot + asr_plot
combined_trends + plot_annotation(
caption = "Source: Health NZ Cancer Web Tool"
)
Figure 1: Historical trends in prostate cancer incidence in NZ men (2009-2022).
# Calculate trend statistics
trend_stats <- data.frame(
Period = c("2009-2015", "2016-2022", "Overall (2009-2022)"),
`Avg Annual Cases` = c(
round(mean(prostate_count_data$cases[prostate_count_data$year <= 2015])),
round(mean(prostate_count_data$cases[prostate_count_data$year >= 2016])),
round(mean(prostate_count_data$cases))
),
`Avg ASR` = c(
round(mean(prostate_asr_data$asr[prostate_asr_data$year <= 2015]), 1),
round(mean(prostate_asr_data$asr[prostate_asr_data$year >= 2016]), 1),
round(mean(prostate_asr_data$asr), 1)
)
)
kable(trend_stats,
caption = "Table 2: Prostate cancer incidence trends by period") %>%
kable_styling(bootstrap_options = c("striped", "hover", "condensed"),
full_width = FALSE)| Period | Avg.Annual.Cases | Avg.ASR |
|---|---|---|
| 2009-2015 | 3200 | 100.3 |
| 2016-2022 | 4087 | 103.4 |
| Overall (2009-2022) | 3643 | 101.9 |
Technical note: Please note annual point incidence / age standardised rates measure the number of new cases per year and are not equivalent to lifetime risk. Lifetime risk calculations require complex actuarial methods involving subjective population assumptions.
References
Annual prostate cancer registration data is from the Health NZ Cancer Web Tool (Health NZ (Te Whatu Ora) 2024). Lifetime risk estimates are from reported figures from Prostate Cancer NZ and the NZ Cancer Society (Prostate Cancer Foundation NZ n.d.; Te Kahui Matepukupuku o Aotearoa (Cancer Society NZ) 2020). Population data is from Stats NZ (Tatauranga Aotearoa (Stats NZ) 16 February 2024, 10:45am).
Report generated on 2025-09-24 using R version 4.5.1