Whole Breast Irradiation With Intensity Modulated Radiotherapy and Simultaneously Integrated Boost for Early Stage Breast Cancer Patients

Inclusion Criteria:

* Eastern Cooperative Oncology Group performance score﹤2
* All patients aged \>18 years and \< 70 years after breast conserving surgery.
* On histological examination, the tumor must be DCIS or invasive adenocarcinoma of the breast.
* Negative nodal status determined by sentinel node biopsy, or axillary dissection. Axillary staging is not required for patients with DCIS
* No evidence of distant metastasis
* Gross disease may be unifocal or multifocal with pathologic (invasive and/or DCIS) tumor size excised with negative margins（\>2mm）
* Surgical treatment of the breast must have been lumpectomy. Re-excision of surgical margins is permitted.
* The patient must consent to be in the study and must have signed an approved consent form.

Exclusion Criteria:

* Eastern Cooperative Oncology Group performance score≧2
* Presence of extensive intraductal component (ductal carcinoma in situ occupying \> 25% of the primary invasive tumour and present adjacent to the primary tumour).Suspicious microcalcifications, densities, or palpable abnormalities (in the ipsilateral or contralateral breast) unless biopsied and found to be benign.
* Proven multicentric carcinoma (invasive cancer or DCIS) in more than one quadrant of separated.
* Metastatic disease (M1)
* Pregnancy or lactating
* Surgical margins that cannot be microscopically assessed or are positive at pathologic evaluation.
* Psychiatric or addictive disorders that preclude obtaining informed consent or adherence to protocol.
* Collagen vascular disease, specifically dermatomyositis with a CPK level above normal or with an active skin rash, systemic lupus erythematosis, or scleroderma.
* Prior breast or thoracic RT for any condition.
* Previous or concomitant malignancies except non-melanoma skin cancer, carcinoma in situ of the cervix, and invasive carcinoma of the colon, thyroid, cervix, or endometrium treated five years prior to study entry.
* Synchronous chemotherapy or target therapy is not permitted.
* Refusal of the patients to be included in the study