When it comes to breast cancer, even small tumours can be aggressive

A study has recently warned that small tumours, less than 1 cm, can be aggressive in patients with early stage of breast cancer.

Researchers found that nearly one in four small tumours was aggressive and patients benefited from chemotherapy as aggressive tumours could be identified by a 70-gene signature.

Lead author Konstantinos Tryfonidis from the European Organisation for Research and Treatment of Cancer (EORTC), Brussels, Belgium said that the results challenge the assumption that all small tumours are less serious and do not need adjuvant chemotherapy.

The analysis included the 826 patients with a primary tumour size of less than 1 cm (pT1abpN0).

Clinical and genomic risks were assessed and 196 patients (24 percent) were found to be at clinical low risk and genomic high risk.

The findings suggested that after five years, very few patients who received chemotherapy experienced disease relapses, showing high rates of distant metastases-free survival, disease-free survival and overall survival, which confirms that they derived benefit from chemotherapy.

"We found that nearly one in four patients with small tumours are at risk of distant metastases and do benefit from chemotherapy," said senior author Fatima Cardoso.

The results showed that it's not only tumour size that is important for breast cancer patients but also tumour biology.

All tumours in the study were small - less than 1 cm - and the lymph nodes were free of cancer (node negative), which in principle should be a signal of good prognosis.

The results also suggested that not all small tumours are the same.

Nearly one in four patients - those identified as genomic high risk - derived benefit from chemotherapy.

The research is presented at ESMO 2017 Congress in Madrid, Spain.