Recurrent phyllodes tumours of the breast: pathological features and clinical implications

Phyllodes tumours (PT) of the breast are fibro-epithelial neoplasms that are known to recur locally in up to 19% of patients. The failure to achieve adequate surgical margins is an important risk factor for local recurrence. This, however, is a common problem as PT are clinically similar to the more common fibro-adenoma and are therefore often locally excised without any gross surgical margins. It is still debatable as to whether it is necessary to subject the patient to repeat surgery to obtain pathologically negative margins after a diagnosis of a benign or borderline PT is made. Although the majority of recurrences are histologically similar to the initial tumour, a malignant recurrence is possible. Malignant tumours can metastasize through the haematogenous route and metastases are associated with a poor prognosis as they are poorly responsive to conventional chemotherapy.

We retrospectively reviewed 37 women who presented with local recurrence over a 10-year period to the Singapore General Hospital. Data, including age at the time of diagnosis, clinical presentation, histological features, type of surgery carried out, clinical progression and characteristics of locally recurrent disease, were analysed. Comparisons were made between those with benign, borderline and malignant tumours, as well as between those who developed a malignant recurrence and those who did not.

The mean age at the time of diagnosis was 39.6 +/- 7.4 years and the mean tumour size was 6.0 +/- 5.1 cm. A total of 22 patients were classified as having benign tumour, 9 as having borderline tumour and 6 as having malignant tumour. Tumour grade did not influence the tumour size, the adequacy of surgical margins or the time interval to local recurrence or the number of recurrences. Local recurrence occurred after a median interval of 20 months. Although malignant tumours tended to recur earlier, this was not found to be statistically significant. The majority of recurrent tumours were histologically similar to the initial tumour; however, seven patients (19%) developed a malignant recurrence from an initially benign or borderline tumour. Although these tumours were larger, recurred more frequently and within a shorter interval, no significant predictive factor was found on multivariate analysis. Distant metastasis developed only in patients with malignant tumours and accounted for all three mortalities in the study.

It may be acceptable to use an expectant management towards benign and borderline tumours that are excised without adequate surgical margins. However, surgery for locally recurrent tumours, as well as malignant tumours, should aim to achieve adequate surgical margins to reduce the risk of local recurrence, particularly that of a malignant recurrence.