Efficacy of radiation therapy in Japanese patients with positive margins after breast-conserving surgery.

BACKGROUND: Additional surgical resection is recommended after breast-conserving surgery if the surgical margin is pathologically positive. However, in clinical practice, radiation therapy is sometimes used instead for several reasons. Irradiation may be appropriate for some patients, but real-world data is still insufficient to establish it as standard treatment. We retrospectively investigated the status of local control in patients who received irradiation for positive margins. METHODS: We investigated 85 patients with positive margins after curative partial mastectomy who were treated with irradiation instead of additional excision during the period 2006-2013. The patients received whole-breast irradiation (43.2-50 Gy) using photon beams and additional tumour-bed boost (8.1-16 Gy) using electron beams. Intrabreast tumour recurrence was defined as secondary cancer within the ipsilateral conserved breast. Surgical margin was defined as positive if tumour cell exposure was pathologically confirmed on the margin. RESULTS: Seven patients (8.2%) developed intrabreast tumour recurrence during a mean observation period of 119 months. As to components of positive margin, 76 cases were positive for an intraductal component, of which seven (9.2%) developed intrabreast tumour recurrence. Meanwhile, all nine cases positive for an invasive component were free from intrabreast tumour recurrence. Two of the intrabreast tumour recurrence cases seemed to develop new lesions rather than recurrence, considering tumour location. The cumulative incidence of intrabreast tumour recurrence over 10 years was 6.1%. Limited to true recurrence, intrabreast tumour recurrence incidence was 4.9%. CONCLUSION: Our real-world data supports irradiation as an alternative to additional surgical intervention for positive margins after breast-conserving surgery and offers a basis for further research.

Comparison of tumors with HER2 overexpression versus HER2 amplification in HER2-positive breast cancer patients.

BACKGROUND: Human epidermal growth factor receptor 2 (HER2)-positive tumors are defined by protein overexpression (3+) or gene amplification using immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH), respectively. HER2-positive tumors have historically included both IHC(3+) and IHC(2+, equivocal)/FISH(+) tumors and received the same treatment. Differences in biology between these two tumor types, however, are poorly understood. Considering anti-HER2 drugs bind directly to HER2 protein on the cell surface, we hypothesized anti-HER2 therapies would be less effective in IHC(2+)/FISH(+) tumors than in IHC(3+) tumors, leading to differences in patient outcomes. METHODS: A total of 447 patients with HER2-positive invasive carcinoma who underwent curative surgery were retrospectively investigated. HER2 status was assessed in surgical specimens, except in patients who received neo-adjuvant chemotherapy, where biopsy specimens were employed. RESULTS: Age, tumor size, lymph node status and ER status were independent factors relating to disease-free-survival, but no difference was observed between IHC(3+) and IHC(2+)/FISH(+) tumors. Kaplan-Meier analysis found patient outcomes did not differ, even after stratifying into those that did (n = 314), or did not (n = 129), receive chemotherapy with anti-HER2 drugs. In 134 patients who received NAC, pathological complete response rates in IHC(3+) and IHC(2+)/FISH(+) tumors were 45% and 21%, respectively. Survival after developing metastasis was significantly shorter in the IHC(2+)/FISH(+) group. CONCLUSIONS: The prognosis of patients with IHC(2+)/FISH(+) tumors did not differ from IHC(3+) tumors. However, the significance of HER2 protein overexpression in relation to treatment response remains unclear and warrants further investigations.

Granular Cell Tumor of the Breast Coexisting with Ductal Carcinoma in situ: Case Report.

Granular cell tumor (GCT) is a benign tumor arising from Schwann cells. GCT of the breast is rare and while predominantly benign, it can be difficult to differentiate from breast cancer by imaging. While it is not generally associated with breast cancer, we here report a rare case of GCT coexisting with ductal carcinoma in situ (DCIS). A 38-year-old Japanese woman had microcalcification suggestive of malignancy in the right upper breast and a 6-cm well-defined mass in the right lower breast. Ultrasonography showed that the lower mass was circular in shape with a clear border, and internal echo level was slightly uneven. Contrast-enhanced magnetic resonance imaging found that the inside was unevenly contrast-enhanced and showed fast/washout enhanced pattern. Hence, imaging could not exclude malignancy. Pathological diagnosis from biopsies taken from the upper calcification and lower mass was DCIS and GCT, respectively. Imaging showed no evidence of continuity between the two, but the patient elected for mastectomy. Final pathological diagnosis confirmed an S-100-positive and keratin-negative GCT for the lower lesion and no histological evidence of continuity. Although GCT is a rare disease, greater awareness of the disease and its imaging findings is needed to avoid overdiagnosis, particularly when it coexists with breast cancer.