Normal tissue complication probability: Does simultaneous integrated boost intensity-modulated radiotherapy score over other techniques in treatment of prostate adenocarcinoma

Aim: The main objective of this study was to analyze the radiobiological effect of different treatment strategies on high-risk prostate adenocarcinoma. Materials and Methods: Ten cases of high-risk prostate adenocarcinoma were selected for this dosimetric study. Four different treatment strategies used for treating prostate cancer were compared. Conventional four-field box technique covering prostate and nodal volumes followed by three-field conformal boost (3D + 3DCRT), four-field box technique followed by intensity-modulated radiotherapy (IMRT) boost (3D + IMRT), IMRT followed by IMRT boost (IMRT + IMRT), and simultaneous integrated boost IMRT (SIBIMRT) were compared in terms of tumor control probability (TCP) and normal tissue complication probability (NTCP). The dose prescription except for SIBIMRT was 45 Gy in 25 fractions for the prostate and nodal volumes in the initial phase and 27 Gy in 15 fractions for the prostate in the boost phase. For SIBIMRT, equivalent doses were calculated using biologically equivalent dose assuming the \u3b1/\u3b2 ratio of 1.5 Gy with a dose prescription of 60.75 Gy for the gross tumor volume (GTV) and 45 Gy for the clinical target volume in 25 fractions. IMRT plans were made with 15-MV equispaced seven coplanar fields. NTCP was calculated using the Lyman-Kutcher-Burman (LKB) model. Results: An NTCP of 10.7 \ub1 0.99%, 8.36 \ub1 0.66%, 6.72 \ub1 0.85%, and 1.45 \ub1 0.11% for the bladder and 14.9 \ub1 0.99%, 14.04 \ub1 0.66%, 11.38 \ub1 0.85%, 5.12 \ub1 0.11% for the rectum was seen with 3D + 3DCRT, 3D + IMRT, IMRT + IMRT, and SIBIMRT respectively. Conclusions: SIBIMRT had the least NTCP over all other strategies with a reduced treatment time (3 weeks less). It should be the technique of choice for dose escalation in prostate carcinoma

Normal tissue complication probability: Does simultaneous integrated boost intensity-modulated radiotherapy score over other techniques in treatment of prostate adenocarcinoma

Aim: The main objective of this study was to analyze the radiobiological effect of different treatment strategies on high-risk prostate adenocarcinoma. Materials and Methods: Ten cases of high-risk prostate adenocarcinoma were selected for this dosimetric study. Four different treatment strategies used for treating prostate cancer were compared. Conventional four-field box technique covering prostate and nodal volumes followed by three-field conformal boost (3D + 3DCRT), four-field box technique followed by intensity-modulated radiotherapy (IMRT) boost (3D + IMRT), IMRT followed by IMRT boost (IMRT + IMRT), and simultaneous integrated boost IMRT (SIBIMRT) were compared in terms of tumor control probability (TCP) and normal tissue complication probability (NTCP). The dose prescription except for SIBIMRT was 45 Gy in 25 fractions for the prostate and nodal volumes in the initial phase and 27 Gy in 15 fractions for the prostate in the boost phase. For SIBIMRT, equivalent doses were calculated using biologically equivalent dose assuming the α/β ratio of 1.5 Gy with a dose prescription of 60.75 Gy for the gross tumor volume (GTV) and 45 Gy for the clinical target volume in 25 fractions. IMRT plans were made with 15-MV equispaced seven coplanar fields. NTCP was calculated using the Lyman-Kutcher-Burman (LKB) model. Results: An NTCP of 10.7 ± 0.99%, 8.36 ± 0.66%, 6.72 ± 0.85%, and 1.45 ± 0.11% for the bladder and 14.9 ± 0.99%, 14.04 ± 0.66%, 11.38 ± 0.85%, 5.12 ± 0.11% for the rectum was seen with 3D + 3DCRT, 3D + IMRT, IMRT + IMRT, and SIBIMRT respectively. Conclusions: SIBIMRT had the least NTCP over all other strategies with a reduced treatment time (3 weeks less). It should be the technique of choice for dose escalation in prostate carcinoma

Normal tissue complication probability of fibrosis in radiotherapy of breast cancer: Accelerated partial breast irradiation vs conventional external-beam radiotherapy

Aims: Radiotherapy forms an integral part of breast-conserving treatment in early-stage breast cancer. Subcutaneous fibrosis of the treated breast is an important late effect in whole-breast irradiation. The aim of this study was to compare the normal tissue complication probability (NTCP) for radiation-induced fibrosis in treated breast using accelerated partial-breast irradiation (APBI) vs conventional treatment. Materials and Methods: Ten postoperative early-stage breast cancer patients (T1N0M0) were included in this dosimetric analysis. APBI treatment was planned using conformal radiotherapy technique and conventional treatment plans included two tangential portals. All the APBI treatment plans were made with five non-coplanar beams with 6 MV photons. The prescription dose was 38 Gy in 10 fractions for the APBI treatments and 50 Gy in 25 fractions, followed by a boost dose of 16 Gy in 8 fractions, for the conventional treatments. We used Lyman′s relative-seriality model and the breast fibrosis NTCP model fitting parameters for the study. Results: The equivalent uniform dose (EUD) was 30.09 Gy and 50.79 Gy in APBI and conventional treatment, respectively. The mean NTCP values for ipsilateral breast fibrosis in APBI and conventional treatment were 0.51 and 25.66%, respectively. Using the paired t-test, a statistically significant difference was seen in the breast fibrosis NTCP values for APBI vs conventional treatment (P < 0.001). Conclusions: APBI reduces the ipsilateral breast fibrosis compared to conventional whole-breast treatment in early-stage breast cancer

Reirradiation for progressive brain metastases

Brain metastases constitute one of the most common distant metastases of cancer and are increasingly being detected with better diagnostic tools. The standard of care for solitary brain metastases with the primary disease under control is surgery followed by radiotherapy. Radiotherapy is also the primary modality for the treatment of multiple brain metastases, and improves both the quality of life and survival of patient. Unfortunately, more than half of these treated patients eventually progress leading to a therapeutic dilemma. Another course of radiotherapy is a viable but underutilized option. Reirradiation resolves distressing symptoms and has shown to improve survival with minimal late neurotoxicity. Reirradiation has conventionally been done with whole brain radiotherapy, but now studies with stereotactic radiosurgery have also shown promising results. In this review, we focus on reirradiation as a treatment modality in such patients. We performed a literature search in MEDLINE (www.pubmed.org) with key words brain metastases, reirradiation, whole brain radiotherapy, stereotactic radiosurgery, interstial brachytherapy, and brain. The search was limited to the English literature and human subjects

Reirradiation for progressive brain metastases

Brain metastases constitute one of the most common distant metastases of cancer and are increasingly being detected with better diagnostic tools. The standard of care for solitary brain metastases with the primary disease under control is surgery followed by radiotherapy. Radiotherapy is also the primary modality for the treatment of multiple brain metastases, and improves both the quality of life and survival of patient. Unfortunately, more than half of these treated patients eventually progress leading to a therapeutic dilemma. Another course of radiotherapy is a viable but underutilized option. Reirradiation resolves distressing symptoms and has shown to improve survival with minimal late neurotoxicity. Reirradiation has conventionally been done with whole brain radiotherapy, but now studies with stereotactic radiosurgery have also shown promising results. In this review, we focus on reirradiation as a treatment modality in such patients. We performed a literature search in MEDLINE (www.pubmed.org) with key words brain metastases, reirradiation, whole brain radiotherapy, stereotactic radiosurgery, interstial brachytherapy, and brain. The search was limited to the English literature and human subjects