How is hormone receptor status related to prognostic factors in metastatic breast cancer?

This paper evaluates whether prognostic factors(factors that predict outcome of disease) have different effect depending on hormone receptor status in metastatic breast cancer

Metastatic breast cancer (cancer that has spread) is generally incurable with a low survival rate. Several prognostic factors have been identified. Many of these factors are related to hormone receptor status (presence or absence of hormone receptor). Hence, this study evaluates prognostic factors for survival in relation to hormone receptor status. 

Patients were selected from the Netherlands Cancer Registry. Information was collected on patient and tumour characteristics, treatment and follow-up. 2001 patients who developed metastatic disease were included in the analysis.

Of 2,001 patients, 65% had a HR positive tumour(HR present). HR positive patients were more likely to have lobular carcinoma (cancer beginning at breast lobules), small tumour size and negative HER2-Neu (human epidermal growth factor 2, a protein). They were also more likely to have a longer metastatic free interval (time without metastasis) and bone metastases compared to HR negative  patients. There were 1627 deaths among 2,001 patients. On average, HR negative patients survived 8 months while HR positive patients survived 19 months.

Among HR negative patients, those with 1-3 positive lymph nodes (cancer present) had a 42% increase in risk of death than those with negative lymph nodes. However, HR positive patients had a 13% decrease in risk of death for those with 1-3 positive lymph nodes.

Among HR negative patients, patients who are HER2-Neu positive had a 43% decrease in risk of death compared to HER2-Neu negative patients. This was less significant in HR positive tumours, where HER2-Neu positive patients had a 18% decrease in risk.

HR positive patients had a 26% increase in risk of death with adjuvant endocrine treatment. Treatment with first line palliative (pain-relieving) chemotherapy was associated with a 69% decrease in risk of death in HR negative patients but only 24% decrease in risk for HR positive patients. 

In conclusion, the authors found that metastatic breast cancer is aggressive in HR negative patients with negative HER-Neu, a short metastatic free interval and multiple metastases. Furthermore, lymph node status, HER2-Neu status, adjuvant endocrine treatment and first-line palliative chemotherapy depends on HR status. 

There is lack of detailed information on performance status (disease impact), co-morbidity (presence of additional disease) and response to primary breast cancer treatment. 

Patients could discuss with their doctor treatment strategies based on their hormone receptor status.