This study will assess results of intraoperative radiotherapy as boost after neoadjuvant chemotherapy in patients with nonmetastatic breast cancer candidate for breast conserving surgery. Recruitment will be done in three treatment centers. Major inclusion criteria comprise of female gender; age between 30 and 70 years; and operable breast cancer patient who is candidate for breast conserving surgery. Major exclusion criterion consist of pregnancy and breast feeding; active collagen vascular diseases; previous history of chest wall radiotherapy; multifocal breast cancer in two separate quadrants of breast; and poor clinical response to the neoadjuvant chemotherapy. The study is unblinded, single-grouped, and prospective. Twenty patients will be incorporated using convenience sampling method and assessed by complete history taking and physical examination, bilateral mammography, and breast/axilla sonography and metastases work-up before the intervention. Then, a detectable marker will be inserted under the guide of sonography in the tumor. Afterwards, the patients will receive neoadjuvant chemotherapy based on the standards of the treating institute. Before each course of chemotherapy, the patients will be examined for clinical response to chemotherapy. At the end of neoadjuvant treatment, the patients will undergo full physical examination and mammographic and sonographic assessment. In case of appropriate clinical response, the patients will undergo lumpectomy two weeks after completion of neoadjuvant treatment. During surgery, the patients will receive 20 gray intraoperative radiotherapy by intrabeam system Zeiss. After surgery, the patients will receive external beam radiotherapy (50 gray to the whole breast and 45 to 50 gray to the supraclavicular lymph node). Patients will be followed up every 3 months during the first 2 year, and then every 6 months until 5 years by physical examination and annual mammography (or sonography in case of dense breast). Patients will be analyzed based on complications of treatment and two-year disease-free survival.