Treatment outcome of ductal carcinoma in situ patients treated with postoperative radiation therapy

Proportion and clinical outcomes of postoperative radiotherapy omission after breast-conserving surgery in women with breast cancer

PURPOSE

The present study was conducted to investigate the proportion and clinical outcomes of breast cancer patients who did not receive postoperative radiotherapy (PORT) after breast-conserving surgery (BCS).

METHODS

This retrospective study included all breast cancer patients received curative BCS without PORT between 2003 and 2013. In the PORT omission group, characteristics and local recurrence differences were compared between the recommended group and the refused group. To compare the local recurrence-free survival (LRFS) of the PORT omission group and the control group who received PORT, subjects were selected by using the pooled data of patients treated between 1994 and 2007.

RESULTS

During the study period, 96 patients did not receive PORT among a total of 6,680 patients who underwent BCS. Therefore, the overall rate of PORT omission was 1.4%. Among the 96 patients, 20 were recommended for PORT omission (recommended group) and 76 refused PORT (refused group). The median follow-up period of all study participants was 19.3 months (range, 0.3-115.1 months). Patients in the recommended group were older (p=0.004), were more likely to be postmenopausal (p=0.013), and had more number of positive prognostic factors compared with the refused group. Overall, 12 cases of disease recurrence, including 11 cases of local recurrence, developed in the PORT-refused group. The LRFS of the PORT-omission group was significantly inferior to that of patients who received PORT after BCS (p<0.001). In the PORT-omission group, significant favorable prognostic factors for LRFS were having histologic grade 1 or 2 disease (p=0.023), having no axillary lymph node metastasis (p=0.039), receiving adjuvant endocrine therapy (p=0.046), and being in the recommended group (p=0.026).

CONCLUSION

The rate of PORT omission in the present study is very low among women who underwent surgery compared to that of other studies worldwide. PORT omission is significantly related to a high local recurrence rate.

Is radiotherapy necessary for intermediate risk ductal carcinoma in situ after breast conserving surgery?

Identifying ductal carcinoma in situ (DCIS) patients at highest risk for recurrence after breast conserving surgery (BCS) remains a clinical concern. Subjecting all such patients to radiotherapy may be unnecessary. The Van Nuys Prognostic Index (VNPI) is a simple scoring system for predicting the risk of local recurrence in patients with DCIS. We reviewed patients with DCIS applying the VNPI score system. A total of 184 DCIS patients who underwent surgery at our institution between January 2003 and December 2011 were identified. Patients were not treated according to VNPI guidelines; rather, radiation therapy was applied at each surgeon’s discretion. All patients with hormonal receptor positive tumors were treated with hormonal therapy. Pathology reports were reviewed and VNPI scores of each DCIS calculated. Of the 184 patients, 52 (28.3%), 115 (62.5%) and 17 (9.2%) had low, intermediate and high VNPI scores, respectively. Six of the 184 patients (3.3%) developed ipsilateral local recurrence, five in the intermediate and one in the high VNPI score group. Of the five in the intermediate group, three (60%) were in patients with ER-negative tumors. VNPI score itself was not associated with recurrence (P = 0.145). Factors associated with recurrence included tumor size (hazard ratio [HR] 6.88), grade (HR 9.07) and hormone receptor status (HR 11.75). Radiotherapy did not significantly improve recurrence rates in patients with low and intermediate risk DCIS, especially in those with ER-positive tumors. Radiotherapy can be omitted in patients with ER-positive intermediate score DCIS and in patients with low score DCIS.

Influence of boost radiotherapy in patients with ductal carcinoma in situ breast cancer: a multicenter, retrospective study in Korea (KROG 11-04)

To estimate the effect of boost radiotherapy on local recurrence-free survival (LRFS) in patients with ductal carcinoma in situ (DCIS) breast cancer. We included patients from nine institutions who met the following criteria: having Tis, age 18 years or older, having breast conserving surgery (BCS) and radiotherapy within 12 weeks after surgery. From 1995 through 2006, 728 patients were analyzed retrospectively by the Korean Radiation Oncology Group. All patients received whole-breast radiation therapy (WBRT) after BCS. 232 patients (31.9 %) also received boost radiation therapy (RT) (median 10 Gy). After median follow-up of 82 months, 5-year LRFS was 98.4 % and 10-year LRFS was 95.8 % for all patients. There was no statistically significant difference of LRFS between the boost and no-boost groups. Nineteen (2.6 %) patients had ipsilateral breast recurrences, including 12 of invasive recurrence and 7 DCIS. The presence of the HER2 receptor was associated with more invasive recurrences. Nine (1.2 %) patients developed contralateral breast cancer, including six invasive breast cancer and three DCIS. In the multivariate analysis, only the margin status was a significant prognostic factor for LRFS. Boost RT was not associated with further improvement of local control in DCIS after BCS and WBRT. HER2 receptor-positive patients may need further treatment with the anti-HER2 agents.