Prostate cancer--are ethnic minorities disadvantaged?

This study, investigating ethnic differences in the diagnosis and treatment of prostate cancer, was performed because of a perceived paucity of Măori men receiving treatment for localised prostate cancer in the greater Wellington region. It was considered that if real differences could be demonstrated between Măori and non-Măori, it would raise questions as to whether cancer services were equally accessible to all sections of the population, one of the main objectives of the New Zealand Cancer Control Strategy.

The database for this study includes men from the greater Wellington region, presenting with clinically localised prostate cancer between 1996 and 2007, who were treated using three defined protocols. There were 271 men with low-risk prostate cancer treated with brachytherapy (permanent iodine seed implantation), and 188 men with intermediate- or high-risk prostate cancer who were entered into sequential clinical trials run by the Trans-Tasman Radiology Oncology Group (96.01 and RADAR 03.04) and treated with radical external beam radiotherapy. Each man on the database was allocated to a major ethnic group based on ethnic categories defined in the 2006 New Zealand Census. Comparisons were then made of the observed ethnic mix of men in the low- and intermediate/high-risk groups with the expected percentages derived from Census and Cancer Registry data.

Ten Măori men were on the database, compared to 44 expected, and one Pacific man, compared to 37 expected. The same pattern of under-representation of these ethnic minorities was seen for both low-risk and intermediate/high-risk localised prostate cancer.

As Cancer Registry data indicate that Măori have a lower incidence of prostate cancer compared to non-Măori, but a higher mortality rate and ratio (deaths/registrations), it is probable that during the period covered by this study, Măori were more likely to present with advanced cancer no longer confined to the prostate. The most likely explanation for this is that Măori have a cultural reluctance to present for health care until forced to by disabling symptoms. Longstanding negative messages from government agencies on the value of prostate cancer screening have done little to encourage the attitudinal change necessary for earlier, and more beneficial, engagement with health services.