Speaker
Prof.
Satish B S Rao
(Division of Radiobiology & Toxicology, Manipal Life Sciences Centre, Manipal University)
Description
With improving overall survival rates, there is emerging focus on the quality of life after adjuvant cancer treatment. During radiotherapy, unacceptable normal tissue toxicity is the major limiting factor for delivering a tumoricidal dose. Therefore, it is of great importance to determine whether variations in inherent cellular radiosensitivity along with extrinsic factors have greater influence on individual differences in the normal tissue adverse reactions. Assays and parameters to predict, what severity of the skin reactions will develop after the treatment remains absolutely necessary for clinicians to make therapeutic choices for personalized therapy. Aim of the present investigation is to assess the usefulness of γH2AX assay in predicting the radiotherapy induced normal tissue response among breast cancer patients.
Breast cancer patients (n=42) selected for the study were treated with radiation therapy using Linac X-ray linear accelerator. The individual radiosensitivity was determined by the microscopic scoring of γH2AX foci in peripheral lymphocytes collected prior to radiotherapy, and irradiated in vitro with 2 Gy X-rays. The DSB damage and repair capacity (as residual damage) at different repair time points (0.25, 3 and 6h) was analyzed. Acute skin adverse reactions were scored by Radiation Therapy Oncology Group (RTOG) criteria.
There exists a clear interindividual variation in radiosensitivity among the subjects (CV=15.54%) with reference to their residual damage. Based on the toxicity grading criteria patients were grouped in to non-over-reactors (G0 & G1) and over-reactors (G2 & G3). These groups showed a significant difference (P=0.0282) in their residual damage levels. Linear regression analysis of initial damage, residual damage (3h & 6h) with RTOG grades revealed a significant association (R2=0.1175, P=0.0263) at 6h of post repair time point with radiotherapy induced acute skin reactions. Although, this study has limited sample size we could able to associate the residual damage with the development of acute skin reactions. With additional sample size this study may have more valid findings with clinical implications for tailoring radiotherapy.
The facilities of Manipal University and the financial support from Department of Biotechnology, Government of India (BT/01/COE/06/02/07) are gratefully acknowledged.
Primary author
Prof.
Satish B S Rao
(Division of Radiobiology & Toxicology, Manipal Life Sciences Centre, Manipal University)
Co-authors
Dr
Donald Fernandes
(Department of Radiotherapy & Oncology, Shiridi Sai Baba Cancer Hospital and Research Center, Manipal University, Manipal – 576 104, Karnataka, India)
Mr
Goutham H V
(Division of Radiobiology & Toxicology, Manipal Life Sciences Centre, Manipal University, Manipal – 576 104, Karnataka, India)
Dr
Guruprasad K P
(Division of Biotechnology, Manipal Life Sciences Centre, Manipal University, Manipal – 576 104, Karnataka, India)
Mr
Kamalesh Mumbrekar
(Division of Radiobiology & Toxicology, Manipal Life Sciences Centre, Manipal University, Manipal – 576 104, Karnataka, India)
Prof.
Satyamoorthy Kapaettu
(Division of Biotechnology, Manipal Life Sciences Centre, Manipal University, Manipal – 576 104, Karnataka, India)
Dr
Vadiraja B M
(Department of Radiation Oncology, Manipal Hospital, Bangalore, Karnataka, India)
