Impact

Breast cancer disease and death in Australia

Breast cancer is the most commonly diagnosed cancer in women in Australia (excluding non-melanoma skin cancer)^[1], with one in eight women diagnosed by the age of 85^[1]. In 2015, 16,852 women were diagnosed with breast cancer, accounting for 28% of all cancers diagnosed in women that year^[1].

Breast cancer was estimated to be the sixth leading cause of disease burden in Australian women in 2012, measured by disability-adjusted life years^[2]. It accounted for 4% of the disease burden, and 24% of the cancer burden in women^[2].

Breast cancer is the second most common cause of cancer death in women in Australia, and the fourth most common overall^[1]. In 2016, there were 2,976 deaths in women due to breast cancer, accounting for 15% of all cancer deaths in women that year^[1].

Breast cancer was the third leading cause of mortality burden (measured by years of life lost) in women in 2015, accounting for 6% of the mortality burden^[3]. In 2015, breast cancer was estimated to cause 60,338 years of life lost to Australian women^[3].

Although much more common in women, breast cancer affects a small number of men each year. In 2015, 152 men were diagnosed with breast cancer^[4]. In 2016, there were 28 breast cancer deaths in men^[4].

Trends

The number of breast cancer cases diagnosed in Australian women increased significantly between 1982 and 2015, from 5,313 cases to 16,852^[4]. This is in part due to a growing and ageing population, but indicates a real increase, with the incidence rate over this period increasing from 70 diagnoses per 100,000 women to 140 per 100,000 women^[4]. The sharp increase in breast cancer diagnoses, seen particularly between 1990 and 1995, has been associated with the introduction of the BreastScreen Australia population-based mammography screening program in 1991. The screening program was phased in between 1991 and 1995, and it is likely that the associated increase in incidence was due to the earlier detection of cases that would not otherwise have been detected during that period.

Breast cancer incidence in women aged 50 and over increased in the years leading up to 2001, but decreased in the following two years, mirroring patterns of the prescription of hormone replacement therapy in Australia which fell by 40% from 2001–2003. Over the same time period, there was no significant change in breast cancer incidence among women under 50 years of age^[5].

Overall, the rate of diagnosis has remained relatively stable since 1995^[2]. The rate of diagnosis is projected to remain stable until 2020, at around the current rate of approximately 113–114 cases per 100,000 women^[6]. However, projected population changes mean the absolute number of diagnoses is estimated to increase from 14,290 in 2011 to 17,210 in 2020^[6].

Breast cancer mortality in Australia has decreased steadily since the mid-1990s. Between 1994 and 2012, the age-standardised mortality rate decreased by 30% from 31 per 100,000 population to 21 per 100,000^[7][2]. Between 1991 (when the BreastScreen Australia program was introduced) and 2010, the breast cancer mortality rate decreased by 37% among women in the target age range of 50–69 years^[8].

The decrease in mortality over time is attributed to increased early detection through BreastScreen Australia, and advances in management and treatment^[9][10].

Aboriginal and Torres Strait Islander Australians

During the period 2004–2008, the incidence rate for breast cancer was lower in women from Aboriginal and Torres Strait Islander communities compared with their non-Indigenous counterparts (81 per 100,000 compared with 103 per 100,000)^[2].

Despite this lower incidence rate, breast cancer mortality rates for Aboriginal and Torres Strait Islander women do not differ significantly from those of non-Indigenous women (21 deaths per 100,000 compared with 23 per 100,000)^[2]. However, a recent study has suggested that the risk of breast cancer mortality is significantly higher in Aboriginal and Torres Strait Islander women once adjustment has been made for a range of possible confounding factors, such as socio-demographic factors, tumour size, nodal spread and time from last screen to diagnosis. Estimates range from a 68% increased risk to approximately double the risk of death from breast cancer for Aboriginal and Torres Strait Islander women compared with non-Indigenous women^[11][12].

Indigenous women diagnosed with breast cancer between 2003 and 2007 also had a 100% higher risk of dying from any cause by 2010 than non-Indigenous women^[13].

These differences in incidence and mortality may be, in part, due to different patterns in breast cancer screening and management among Aboriginal and Torres Strait Islander women^[2]. Women from Aboriginal and Torres Strait Islander communities participate less frequently in screening and re-screening compared with non-Indigenous women^[11][12]. They are also less likely to attend post-screening assessment within the recommended 28 days when recalled and have larger breast cancers at diagnosis^[11][12].

Economic impact

The global cost of breast cancer in 2008 was estimated at US $88 billion, making it the third most expensive cancer after lung and bowel cancer^[14].

In 2008‒2009 in Australia, health expenditure on breast cancer was $411 million, making it the most expensive cancer in Australian women^[15]. The total health system expenditure comprised $175 million for BreastScreen Australia, $147 million on hospital inpatient costs, $60 million on prescription pharmaceuticals and $29 million on out of hospital costs^[15].

BreastScreen Australia expenditure increased from $95.9 million in 2000–01, to $175 million in 2008–09^[15].

A study of the cost of cancer in New South Wales, commissioned by Cancer Council NSW estimated, based on 2005 data, that the lifetime personal cost of breast cancer was $653,600 per person. This figure comprised a financial cost of $64,300 and a ‘burden of disease’ cost of $589,300^[16].

A Queensland-based study found that the majority of the personal economic burden associated with breast cancer was due to lost income, health service expenditure and lost unpaid work^[17]. Based on 2002–2004 data, the average personal economic burden of breast cancer within 18 months of diagnosis was $3,446, including indirect costs of $2,134^[17]. Women with positive lymph nodes (indicative of more advanced disease) reported nearly twice the costs of women with negative lymph nodes – $5,006 compared with $2,650^[17]. Treatment modalities vary according to staging of disease. In general, more advanced breast cancer requires more complex and costly treatment and care, with overall costs for a typical stage IV case in Australia being triple those for a case diagnosed at stage I^[18].

The economic burden of breast cancer is likely to have changed dramatically since these analyses due to changes in available treatments for the disease over the past several years. More recent studies on the cost of breast cancer in Australia are needed.