Author/Authors :
Rezaeijo, S.M Department of Medical Physics - Faculty of Medical Sciences - Tarbiat Modares University, Tehran, Iran , Hashemi, B Department of Medical Physics - Faculty of Medical Sciences - Tarbiat Modares University, Tehran, Iran , Mofid, B Department of Radiation Oncology - Faculty of Medicine - Shahid Beheshti University of Medical Sciences, Tehran, Iran , Bakhshandeh, M Department of Radiology Technology - Faculty of Allied Medical Sciences - Shahid Beheshti University of Medical Sciences, Tehran, Iran , Rostami, A Department of Medical Physics - Faculty of Medicine - Iran University of Medical Sciences, Tehran, Iran , Molana, S.H Department of Radiation Oncology - Roshana Radiation Oncology Center, Tehran, Iran
Abstract :
Background: Comparing three whole pelvic radiotherapy (WPRT) procedures as well as two local radiotherapy (LRT) procedures with each other for the treatment of prostate cancer patients using dosimetric parameters and radiobiological models: tumor control probability (TCP), normal tissue
complication probability (NTCP), and equivalent uniform dose (EUD).
Materials and Methods: Two groups of prostate cancer patients underwent
WPRT (n=16) and LRT (n=16) procedures. In the WPRT group, the patients
treated with two intensity modulated radiation therapy (IMRT+IMRT)
procedures at two consecutive phases. Then, two other techniques including
a three dimensional (3D) conformal radiation therapy (3DCRT) phase followed
by an IMRT phase (3DCRT+IMRT) and also two consecutive 3DCRT procedures
(3DCRT+3DCRT) were carried out on the patients' data. In the LRT group, the
patients treated with just an IMRT technique. Then a 3DCRT technique was
also performed on the patients' data. All the WPRT and LRT procedures
compared with each other based on the dosimetric parameters and
radiobiological models. Results: The mean of dosimetric parameters did not
exceed the specified dose constraints for the bladder and femoral heads in
the 3DCRT+ IMRT, and for the bladder in the 3DCRT technique. In the WPRT
and LRT procedures, the TCP values for the prostate did not reveal any
significant differences (P>0.05). The NTCP results in accordance with the
dosimetric results for the organs at risk (OARs) showed a significant decrease
in the IMRT+IMRT (WPRT) and the IMRT (LRT) techniques (P<0.05). However,
the EUD results were dependent on the type of the procedure and OARs.
Conclusion: For selecting the appropriate treatment technique for each
prostate cancer patient, a compromise between the dosimetric and radiobiological evaluation of the WPRT and LRT procedures should be considered.
Keywords :
Prostate cancer , whole pelvic radiotherapy (WPRT) , local radiotherapy (LRT) , dosimetric parameters , radiobiological models
