Small Tumors in Early Stage Breast Cancer Can Match Aggression in Larger Counterparts

Small node negative tumors can be aggressive, even if classified as clinical low risk.

Small tumors can be just as aggressive as their larger counter parts, according to a study.

Findings from a sub analysis presented at the ESMO 2017 Congress in Madrid showed nearly 1 in 4 small tumors were aggressive and patients benefitted from chemotherapy.

“Our results challenge the assumption that all small tumors are less serious and do not need adjuvant chemotherapy,” lead author Dr Konstantinos Tryfonidis said in a press release.

The sub analysis included 826 patients with early stage breast cancer in the MINDACT study, with a primary tumor less than 1 cm in size.

After assessing for clinical and genomic risks, the investigators found 24% of patients were clinical low risk and genomic high risk.

Participants who were clinical low risk and genomic high risk were randomized to receive either chemotherapy or no chemotherapy.

At 5 years, the results of the study showed few patients who received chemotherapy experienced disease relapses. Furthermore, participants in the chemotherapy arm showed high rates of distant metastases-free survival, disease-free survival, and overall survival, according to the release.

“We found that nearly 1 in 4 patients with small tumors are at risk of distant metastases and do benefit from chemotherapy,” senior author Dr Fatima Cardoso said in the release. “This was striking because based on clinical criteria alone you would say that these tumors are not aggressive and therefore patients do not need chemotherapy. But 24% of small tumors had an aggressive biology, which shows that not all small tumors are the same.”

The findings highlight the importance of tumor size and biology and its role in aggressive cancer.

“This study shows that it’s not only tumor size that is important for breast cancer patients but also tumor biology,” commented Dr Evandro de Azambuja, head of the Medical Support Team, Academic Promoting Team at Jules Bordet Institute in Belgium. “All tumors 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. But nearly 1 in 4 patients––those identified as genomic high risk–––derived benefit from chemotherapy.

“Small node negative tumors can be very aggressive, even if they are classified as clinical low risk. Tumor biology needs to be taken into account when deciding adjuvant treatments in this patient population. One cannot forget the patient’s age, performance status, comorbidities, and, preferences during the discussion.”