To evaluate the effect of the simulation method on recurrence among the patients who received radiotherapy after breast-conserving surgery (BCS) for early breast carcinoma.

Between 1995 and 2000, 70 patients with stage I-II breast carcinoma underwent breast-conserving surgery and adjuvant radiotherapy. Twenty nine patients (41.4%) were simulated with the 2D contour-based method (September 1995 to August 1997) and 41 patients (58.6%) were simulated with the 3D CT-based method (September 1997 to February 2000). To analyze the effect of the simulation method, the patient and treatment characteristics were compared.

The characteristics were similar for the patients between the 2D contour-based simulation group and the 3D CT-based simulation group. During a median follow-up period of 75 months, 4 (13.8%) of 29 patients who were treated with 2D simulation and 1 (2.4%) of 41 patients who were treated with 3D simulation group developed treatment failure. The five-year survival rates were 89.2% and 95.1% between the 2D and 3D simulation groups (p=0.196). The five-year disease free survival (DFS) rates were 86.2% and 97.5% between the 2D and 3D simulation groups (p=0.0636). On univariate analysis, age > 40 (p= 0.0226) and the number of dissected axillary lymph node ≥ 10 (p=0.0435) were independent predictors of improved 5-year DFS.

Although our data showed marginal significance for the DFS between the two groups, it is insufficient, due to the small number of patients in our study, to prove whether 3D CT-based simulation might improve the DFS and reduce the risk of recurrence when compared with 2D contour-based simulation. Further study is needed with a larger group of patients.

Breast-conserving therapy (BCT) is a practical alternative to mastectomy for treating ductal carcinoma in situ (DCIS). We reviewed our experience for treating patients with DCIS of the breast to evaluate the outcome after performing breast-conserving surgery plus radiotherapy (BCS-RT).

Between January 1983 and December 2002, 25 patients with clinically or mammographically detected DCIS were treated by BCS-RT. One patient was diagnosed with bilateral DCIS. Thirteen cases (50%) had symptomatic lesions at presentation. All 26 cases of 25 patients underwent BCS such as lumpectomy, partial mastectomy or quadrantectomy. All of them received whole breast irradiation to a median dose of 50.4 Gy. Twenty-four cases (92.3%) received a boost to the tumor bed for a median total dose of 59.4 Gy. The median follow up period was 67 months (range: 38 to 149 months).

Two cases (7.7%) experienced ipsilateral breast tumor recurrence (IBTR) after BCS-RT. The histology results at the time of IBTR showed invasive ductal carcinoma (IDC), and the median time to IBTR was 25.5 months. On the univariate analysis, there were no significant factors associated with IBTR in the DCIS patients. The three-year local recurrence free survival rate was 96.0% and the overall survival rate was 96.3%.

After the treatment for DCIS, the IBTR rate in our study was similar to other previous studies. Considering that we included patients who had many symptomatic lesions, close or positive margins and less that complete early data, our result is comparable to the previous studies. We could not find the prognostic significant factors associated with IBTR after BCS-RT. A longer follow up period with more patients would be required to evaluate the role of any predictive factors and to confirm these short-term results.