Re: Breast cancer screening and diagnosis

I am writing regarding the article “Breast cancer screening and diagnosis in British Columbia” by Barbara Poole and colleagues [BCMJ 2008;50(4):198-205]. Despite substantial decreases in breast cancer mortality in the past 20 years, too many women are still failing to make full use of what is probably the most significant advance in the fight against breast cancer: annual screening mammography beginning at age 40.

I believe the authors of the article missed an opportunity to highlight a serious gap in the health care provided to women of BC.

It has been well established that women who have an annual screening mammogram beginning at age 40 enjoy an unequivocal survival advantage over those women who don’t. Indeed, mammography is the only intervention known to reduce breast cancer mortality. The decrease in mortality is greatest when mammography is performed annually, and is seen in women in their 40s as well as the 50- to 79-year-old cohort.

It is important for physicians on the front line to distinguish between the public policies that were the focus of this article and what might be best for individual patients. Best practices would have all patients begin annual screening mammography no later than age 40, whereas public policies (set in part by bureaucrats) have established tagets that I believe are exceptionally weak. 

For example, while participation rates as high as 92% have been reported in some jurisdictions, Canada’s target is only 70%. Left unsaid is why 30% of women should not make use of this potentially lifesaving technology.

Furthermore, participation rates as typically defined in Canada count women who have had a mammogram in the prior 2 years, not the prior 12 months, thus overestimating the number of women who are using screening mammography optimally. The authors imply as much by pointing out that, of the more than 1 million women between 40 and 79 in the province, only 256942 had a screening mammogram in 2005. 

This amounts to an annual participation rate of about 25%, shockingly low whether compared with the weak Canadian target, other jurisdictions, and comparable interventions such as seatbelt use and vaccinations.

Finally, the article neglected to mention that public policy focuses on women at average risk. It is impor­tant to note that women at high risk benefit from a combination of annual screening mammography plus annual screening breast MR, yet the latter service is rarely used in BC.

Perhaps the BCMJ could complement this otherwise fine review of public policy with an article focused on how physicians can help individual women benefit best from modern breast imaging modalities. 

—Ian Gardiner, MD
Vancouver