Benign lumps can be a sign of cancer

• Identifying and closely monitoring these women could help save lives, the Mayo Clinic team believe.
• Although most non-cancerous breast lumps do not increase future risk of breast cancer, they found faster growing and more abnormal types did.
• This finding, in the New England Journal of Medicine, held even if there was no family history of breast cancer.
• The first sign may be a lump in the breast.
• In the Mayo Clinic study, the researchers looked at biopsy samples from 9,087 women aged 18 to 85 with benign breast lumps that had been taken at their clinic between 1967 and 1991.
• They asked a pathologist who did not know the diagnoses of the women to assign the lesions to one of three categories - proliferative (faster growing), non-proliferative and atypical (abnormal).
• Women with proliferative or atypical benign tumour samples were more likely to have developed breast cancer than those who had non-proliferative benign breast lumps.
• According to the study, six out of 100 women with a non-proliferative benign breast lump would develop cancer within 15 years, compared to 10 out of 100 women with proliferative benign breast lumps and 19 out of 100 women with atypical benign breast lumps.
• For women of the same age, in general the risk of developing breast cancer over 15 years is five per 100.
• Lead researcher Dr Lynn Hartmann suggested women who have a breast lump biopsy that is benign might want to discuss the possibility of additional risks with their doctors.
• Professor Charles Coombes at Cancer Research UK said: "This is an important study which demonstrates that patients who have had a breast operation for benign breast disease showing abnormal cells should be closely monitored and be on long-term follow-up.