STUDY OF EARLY RADIATION PNEUMONITIS IN CARCINOMA BREAST AND LUNG TREATED WITH RADIOTHERAPYJaganath KP, Lokesh V, DR Thejaswini B, Ajay GV, Asha Latha D, Suchandana Bhaumik, Priya Darshini.
Background toxicity of the respiratory system is quite common after radiotherapy of thoracic tumors. Breast and lung cancer patients represent one of the groups for whom there is a long expected survival. The quantification of lung tissue response to irradiation is important in designing treatments associated with a minimum of complication and maximum tumor control.
OBJECTIVE :- To study the impact of lung volume irradiated on early pneumonitis in patients undergoing RT for cancer breast.
METHOD :- The Study was conducted as per ICH GCP guidelines and Ethics Committee approval.This is a prospective study of cancer of breast and lung treated with radiotherapy from February 2004 to January 2005. Computerized tomography (CT) simulation was part of treatment planning. The volume of lung irradiated was calculated by using both CLD method and summation of area technique. Chest x-ray and spirometric tests were done first as a baseline procedure and later at one month and at 3 months after completion of radiotherapy.
Patients of either sex and Karnofsky performance status (KPS)>70 and all cases of carcinoma breast and lung receiving radiotherapy were included.Patients who have received previous chemotherapy with drugs like bleomycin and mitomycin were excluded from the study.
The incidence of RP in carcinoma breast is 3.9%. With conventional technique of treatment planning for carcinoma breast, percentage of lung volume irradiated in majority of cases (16/26) was within 11% and Central Lung Distance (CLD) proved to be best predictor of it.
The spirometry evaluation showed reduction in the percentage values in different compartments patients. Changes were maximum in patients treated with anthracyclin-based chemotherapy also.
INTERPRETATION AND CONCLUSION The incidence of RP of carcinoma breast is 3.9% treated with locoregional radiotherapy, which is accepted globally. The CLD (Central Lung Distance) method of calculation of PIV (Percentage of Irradiated Lung Volume) is recommended. With the conventional 3-field technique of radiotherapy, the lung volume included is within acceptable limits of 11%. The total dose of 45-50 Gy with conventional fractionation and dose/Fr of 180-200 cGy is safer. The spirometry is helpful in assessing the radiation damage of lung. The anthracycline-based chemotherapy can add to the radiation injury to lung and also interval between radiotherapy and chemotherapy should be more than 3 to 4 weeks.
RP(RADIATION PNEUMONITIS); Radiotherapy of Ca Breast; CLD(Central Lung Distance ); PIV(Percentage of Irradiated Lung Volume)
American Journal of Diagnostic Imaging
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