By Karolinska Institutet

Credit: Thirdman from Pexels

The proportion of women with early breast cancer who receive chemotherapy varies significantly across different regions of Sweden. A study from Karolinska Institutet,publishedin the journalBreast Cancer Research, shows that these differences may affect survival among women 65 and older.

The study includes just over 62,000 breast cancer patients diagnosed between 2007 and 2023, with data retrieved from the Swedish National Quality Registry for Breast Cancer (NKBC).

The researchers investigated how often chemotherapy was used in different health care regions and whether these differences were associated with patients' prognosis.

In total, 28% of breast cancer patients received chemotherapy, but its use varied significantly across the country, from 23% in the western health care region to 34.7% in the Stockholm-Gotland health care region.

"We observed clear regional differences in the use of chemotherapy, despite the fact that breast cancer care is based on the same national guidelines," says Johan Hartman, professor at the Department of Oncology-Pathology at Karolinska Institutet and senior consultant at Karolinska University Hospital.

The differences in treatment did not appear to affect survival among women younger than 65. For older women, however, the researchers observed a different pattern. Among women 65 and older, the 10-year mortality rate was 27.9% in the Stockholm-Gotland health care region and 35.8% in the western health care region, a difference of 7.9 percentage points.

Even after taking differences in the biological characteristics of the tumors and socioeconomic factors into account, regional differences in prognosis remained. Health care regions with lower use of chemotherapy had higher mortality rates. The researchers believe that local guidelines and treatment traditions may provide possible explanations for these differences.

"Our results show that common national guidelines are not always sufficient to ensure equal care. Particularly among patients over the age of 65, we see signs that more patients could have received more active treatment—and possibly had a better prognosis—if care had been more consistent across the country," Hartman says.