Metastatic Disease at Breast Cancer Diagnosis: Global Trends

The proportion of patients with breast cancer who have metastatic disease at diagnosis is lowest in North America and highest in sub-Saharan Africa, according to a meta-analysis published in JAMA Oncology.

Researchers also found that patient age and socioeconomic status are associated with breast cancer stage at diagnosis.

For this meta-analysis, the researchers reviewed data from more than 2.4 million breast cancer patients from 81 countries.

The team found that the proportion of breast cancer patients with distant metastatic disease at diagnosis ranged from 0% to 6% in North America. Rates of metastatic disease were also low in Europe and Oceania. In 33 of 36 countries in these regions, less than 10% of breast cancer patients had metastatic disease at diagnosis.

Sub-Saharan Africa, on the other hand, had some of the highest proportions of patients with metastatic disease at diagnosis, ranging from 5.6% to 30.6%. “Five countries of 11 in sub-Saharan Africa had a proportion of metastatic breast cancer cases greater than 24%,” the researchers noted.

The researchers also found that, in 17 of 18 evaluable European countries, at least 60% of breast cancer patients had stage I or II disease at the time of diagnosis. None of the sub-Saharan African countries reached this proportion of stage I-II diagnoses.

The data also showed that patients with lower socioeconomic status were generally more likely to be diagnosed with metastatic disease. For example, in the United States, the proportion of patients diagnosed with distant metastasis was 8% among patients with the lowest socioeconomic status and 4% among those with the highest socioeconomic status.

In addition, older patients were generally more likely to be diagnosed with metastatic disease. In 23 of 25 evaluable countries, older age was associated with larger proportions of metastatic disease at diagnosis. For example, patients aged 70 years or older were at least twice as likely as younger patients to be diagnosed with distant metastasis in Australia, Finland, Spain, and Georgia.

In Israel and Luxembourg, the likelihood of metastatic disease at diagnosis was 3 times higher for patients age 70 and older. France had a 6-fold higher proportion of metastatic diagnoses in patients aged 75 years or older compared with those younger than 50 years.

“To our knowledge, this is the most comprehensive systematic review estimating the global distribution of stage at diagnosis of population-based female breast cancer data to date,” the researchers wrote. “Early diagnosis is needed, especially in lower-income settings where patients are more often diagnosed at more advanced stage and carry a disproportionate share of breast cancer deaths. Improvements in registration and dissemination of cancer stage and harmonizing staging systems to support international comparisons are needed to support effective policies and cancer control plans.”

Reference

Benitez Fuentes JD, Morgan E, de Luna Aguilar A, et al. Global stage distribution of breast cancer at diagnosis: A systematic review and meta-analysis. JAMA Oncol. Published online November 9, 2023. doi:10.1001/jamaoncol.2023.4837

This article originally appeared on Cancer Therapy Advisor