Moderate Hypofractionated Protracted Radiation Therapy and Dose Escalation for Prostate Cancer: Do Dose and Overall Treatment Time Matter?

Abstract

SummaryThis report compares, retrospectively, the 5-year treatment outcomes and toxicity rates of 2 sequential dose escalation regimens of twiceweekly 4 Gy/fractions hypofractionated intensity modulated radiation therapy in patients with localized prostate cancer. A single 4-Gy additional fraction in patients treated with 14 Â 4 Gy resulted in a similar and minimal acute toxicity, in worse moderate to severe urinary and gastrointestinal late effects, but a significantly better biochemical control.Purpose: This was a retrospective study of 2 sequential dose escalation regimens of twice-weekly 4 Gy/fractions hypofractionated intensity modulated radiation therapy (IMRT): 56 Gy and 60 Gy delivered within a protracted overall treatment time (OTT) of 6.5 and 7 weeks, respectively. Methods and Materials: 163 prostate cancer patients with cT1c-T3a disease and nodal involvement risk 20% (Roach index) were treated twice weekly to the prostate AE seminal vesicles with 2 sequential dose-escalated IMRT schedules: 56 Gy (14 Â 4 Gy, nZ81) from 2003 to 2007 and 60 Gy (15 Â 4 Gy, nZ82) from 2006 to 2010. Patient repositioning was made with bone matching on portal images. Gastrointestinal (GI) and genitourinary (GU) toxicities were scored according to the Common Terminology Criteria for Adverse Events version 3.0 grading scale. Results: There were no significant differences regarding the acute GU and GI toxicities in the 2 dose groups. The median follow-up times were 80.2 months (range, 4.5-121 months) and 56.5 months (range, 1.4-91.2 months) for patients treated to 56 and 60 Gy, respectively. The 5-year grade !2 late GU toxicity-free survivals with 56 Gy and 60 Gy were 96 AE 2.3% and 78.2 AE 5.1% (PZ.001), respectively. The 5-year grade !2 late GI toxicity-free survivals with 56 Gy and 60 Gy were 98.6 AE 1.3% and 85.1 AE 4.5% (PZ.005), respectively. Patients treated with 56 Gy showed a 5-year biochemical progression-free survival (bPFS) of 80.8 AE 4.7%, worse than patients treated with 60 Gy (93.2 AE 3.9%, PZ.007). A trend for a better 5-year distant metastasis-free survival was observed among patients treated in the high-dose group (95.3 AE 2.7% vs 100%, PZ.073, respectively). On multivariate analysis, only the 60-Gy group predicted for a better bPFS (PZ.016, hazard ratio Z 4.58).

Intensive Local Radiotherapy Is Associated With Better Local Control and Prolonged Survival in Bone-Metastatic Nasopharyngeal Carcinoma Patients

“…Besides, many patients presented with oligometastasis, and longer survival durations were often observed among them, thus the short fractionation schedules, which sometimes required the need for retreatment (18), were less adequate. Our results suggested the use of intensive dose prescription, which was consistent with the results in hepatocellular cancer (HCC), renal and prostate cancers (19)(20)(21)(22). Kim et al (20) selected HCC patients who were followed up for at least 1 year and a positive dose-response relationship was observed.…”

GLS-driven glutamine catabolism contributes to prostate cancer radiosensitivity by regulating the redox state, stemness and ATG5-mediated autophagy

“…Next day plates were irradiated with 0 Gy, 2 Gy, 4 Gy and 6 Gy of X-rays (Yxlon Y.TU 320; 200 kV X-rays, dose rate 1.3Gy/min at 20 mA, filtered with 0.5 mm Cu). We have irradiated cells with a single dose of 4Gy for some of our experiments, as several clinical studies suggested the safety and efficiency of moderate hypofractionation (doses of 2.5-4 Gy per fraction) for prostate cancer [77][78][79]. After the irradiation, cells were left in the humidified CO2 incubator for 7 to 10 days.…”

Impact of hydrogel spacer injections on interfraction prostate motion during prostate cancer radiotherapy

“…Whole pelvic irradiation was delivered in two patients followed by a hypofractionated boost of 24 Gy in 6 fractions. Details concerning treatment schedules as well as dose constraints for inverse planning have been previously described [13][14][15]. All patients were treated with a volumetric modulated arc therapy on a Novalis TX linear accelerator with a High Definition Millennium HD120 MLC equipped with an on-board imaging device (OBI) and À6 degrees of freedom robotic couch.…”