The proportion of advanced breast cancer versus localised breast cancer in young women appears to be increasing over time, according to Queensland research.
A retrospective study of over 2,000 young women 15-39 years found the incidence rate of first primary breast cancer diagnosed between 1997 and 2014 was relatively stable over time.
However the proportion with advanced disease rose significantly from 63% between 1997 and 2001 to 71% between 2011 and 2014.
Young Indigenous women had higher rates of advanced disease than other women (82% v 67%) while increasing rurality and socioeconomic disadvantage were also associated with more advanced disease.
The study also found tumours with a mixed morphology of ductal and/or lobular were more likely to be advanced (79%) at the time of diagnosis.
Ductal carcinoma was the most common morphology group, accounting for 85% of all cases.
The study found survival improved over time in all young women as a group from 85% for those diagnosed between 1997 and 2001 to 92% for those diagnosed between 2011 and 2014.
“The improvement in survival was only significant, however, among patients with advanced breast cancer, rising from 79% (95% CI = 74%–82%) between 1997 and 2001 to 88% (95% CI = 84%–92%) between 2011 and 2014 ( p < 0.001),” the study authors wrote in the Journal of Adolescent and Young Adult Oncology.
Indigenous women had more than double the mortality risk from breast cancer as non-Indigenous women (five-year, cause-specific survival 67% v 89%; HR 2.68).
“Patients with advanced disease were at a sixfold higher risk of mortality in relationship to those with localised breast cancer (survival of 84% and 97%, respectively, adjusted HR = 6.20; p <0.001).”
“A better understanding of the factors that lead to advanced disease at diagnosis is necessary so that public health programs can then be implemented to aid with prevention and earlier detection,” it said.
The study authors also called for cancer registries to improve the collection of data on stage of cancer at diagnosis.
“Stage data are vital to evaluate changes to incidence and survival over time, which in turn may inform targeted cancer control strategies.”
The study also confirmed five-year, cause-specific survival in young women (88%) was lower than that from comparative data in older women 40-59 years (93%) and 60+ years (91%).
“This survival disparity by age is due, at least in part, to tumours diagnosed at younger ages being more aggressive and hence less responsive to treatment.”