Phase II study on the use of intraoperative radiotherapy in early breast cancer

To report our early experience using the Intrabeam radiotherapy delivery system for intraoperative radiotherapy [IORT] in early breast cancer. This is a prospective phase 2 study carried out at the Department of Surgery and Radiology, King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia from December 2010 to November 2012. Females eligible for breast-conserving surgery with biopsy-proven invasive duct carcinoma, and with a mass of 3 cm, with lymphovascular invasion, multifocal lesion, extensive intraductal carcinoma, and positive nodes. Early and late toxicity were recorded using the Radiation Therapy Oncology Group [RTOG] criteria. Forty-five patients were included with a median age of 54 [range: 27-79 years]. Thirty-six cases [80%] had tumor <3 cm in diameter, and 36 [67%] have pathologically negative axillary lymph node metastases. None of the patients developed delayed wound healing, postoperative infection requiring intravenous antibiotic, or breast seroma requiring aspiration. Sixteen [36%] received EBRT after IORT. Twelve patients developed radiologically proved fat necrosis. The IORT for early stage breast cancer patients using the Intrabeam delivery system was easily implemented in our center with an acceptable toxicity profile and cosmetic outcome

comparison study of radiation dose received during cone beam computerized tomography and portal imaging techniques

Although widely varied in modality and method, all radiographic guidance techniques have one thing in common; they can give a significant radiation dose to the patient; which may have a late radiation stochastic effect on normal body tissues. To quantify and compare radiation doses to the tumour and the surrounding critical organs resulting from the orthogonal pair portal and megavoltage cone beam computarized tomography [MV CBCT] imaging techniques. The dose to the patient resulting from the orthogonal pair and the MV CBCT imaging techniques, has been calculated based on a 6 MV Oncor linear accelerator equipped with an amorphous silicon flat panel. All calculations were done on Eclipse 3D treatment planning system. 18 patients representing three different treatment sites [head and neck, thorax, and pelvis] were analysed. Data from 6 patients for each treatment site were used to calculate the mean doses. Calculations were done for: The integral dose, maximum dose to the patient, dose at the isocenter, and mean dose to the tumour and each critical organ. The absolute dose measured as integral dose, maximum dose to the patient, dose at the isocenter, and mean dose to the tumour and each critical organ was higher for MV CBCT as compared to orthogonal pair technique for all treatment sites. For both techniques, the absolute dose was higher for head and neck and thorax as compared to pelvis. The difference of maximum dose to the patient showed greater variation for head and neck, but not for thorax and pelvis. There are relatively high dose regions generated by MV CBCT that occur inside critical organs as well treatment area and tend to be larger than those generated by the orthogonal pair technique

3D-CRT techniques for simultaneously integrated boost in breast conserving radiation therapy

To evaluate the dosimetric outcomes of two different three dimensional conformal radiation therapy [3D-CRT] of concomitant boost delivery to the intact breast. Ten patients were evaluated using two standard opposed tangents conformal to the whole breast PTV, plus a pair of wedged fields conformal to the boost PTV; all fields have the same isocenter, placed in the whole breast planning target volume [PTV] [WBI] or located in the boost [BI] PTV. Dose Volume Histograms were calculated and analysed for the difference in maximum and minimum doses; also mean doses and volumes receiving 90% and 107% of the prescribed dose. Lung irradiation was analysed in terms of maximum and mean doses. For breast PTV coverage, significant differences were observed only in the maximum doses [62.3Gy Vs. 61Gy, p=0.003] and higher Dose Homogeneity Index DHI [0.66 Vs. 0.64, p=0.003] in favour WBI. For boost PTV coverage, a significant difference between the two techniques with maximum dose [62.6 versus 60.87, p=0.003] as well the DHI [0.97 Vs. 0.94, p=0.002] in favour of WBI. The Conformity Index CI was significantly better in WBI [0.87 Vs. 0.64, p=0.001]. Dose to lung or healthy tissue was not statistically significant difference between the two methods. This study shows a dosimetrical superiority of using the whole breast isocenter technique over boost isocenter technique in whole breast PTV coverage, dose homogeneity index and boost PTV coverage. The clinical significance of this difference needs further clinical studies

Intensity modulated radiotherapy [IMRT] versus dynamic wedge techniques in radiation therapy of the breast; impact on dosimetric parameters and radiation dose to contralateral breast

New techniques of radiation therapy are being introduced in the management of breast cancer. One of the most rapidly emerging new techniques is intensity modulated radiotherapy [IMRT]. The purpose of the study is to compare between two different techniques of radiation therapy of breast cancer for intact breasts after breast conservative therapy [BCT]; IMRT and dynamic wedge [DW] [standard technique] regarding their impact on dosimetric features of the treated breast and the radiation dose received by the contralateral breast. Fourteen female patients with breast cancer treated with BCT and referred for adjuvant radiation therapy at radiation therapy department of King Abdulaziz University hospital; Jeddah Saudi Arabia during the period January 2007-August 2007 had been studied. Their archived CT scans for breasts were retrieved and the two plans [IMRT and dynamic wedge techniques] were implemented in those CT cuts. The dosimetric parameters [maximum dose; minimum dose, mean dose and homogeneity index] for the treated breast as well as the radiation dose received by the other breast [at 5%, 50% and 95% of its volume] were compared between the two techniques. Fourteen patients had been included in the study; their mean age was 44.9 years; 8 were left sided, and 6 right sided and all of them had been referred for radiation therapy after BCT. The mean radiation dose received by DW technique was 50.68 Gy as compared to 51.23 by IMRT [p value: 0.023], the mean homogeneity index [HI] of dynamic wedge technique was 15.36 [ +/- 39 SD] as compared to 7.02 for IMRT [p value 0.001]. Regarding the radiation therapy dose received by the contralateral breast; it had been found that in DW technique; the 5%; 50% and 95% of the volume of the contralateral breast received a mean radiation dose of 1.16 Gy, 0.31 Gy, and 0.097 Gy respectively as compared to 4.11 Gy, 1.33 Gy and 0.82 Gy respectively; a highly significant difference [p value: 0.0001] with significantly higher dose to contralateral breast by IMRT technique as compared to DW technique. Although the IMRT technique achieved a better dose homogeneity as compared to dynamic wedge technique; however; the radiation dose received by the contralateral [normal] breast was significantly higher in IMRT technique. So we have to be cautious if we want to implement the IMRT technique in radiation therapy of breast to avoid unnecessary radiation exposure to the contralateral breast with its possible impact on late incidence of carcinogenesis