Long-term Outcomes of a Dose-reduction Trial to Decrease Late Gastrointestinal Toxicity in Patients with Prostate Cancer Receiving Soft Tissue-matched Image-guided Intensity-modulated Radiotherapy
| Autor: | Ken Yoshida, Gen Suzuki, Tatsuyuki Nishikawa, Satoaki Nakamura, Daisuke Shimizu, Hideya Yamazaki, Haruumi Okabe, Koji Masui, Naomi Sasaki |
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| Rok vydání: | 2017 |
| Předmět: |
Male
Cancer Research medicine.medical_specialty Gastrointestinal Diseases medicine.medical_treatment Urology Tomotherapy 030218 nuclear medicine & medical imaging 03 medical and health sciences Prostate cancer 0302 clinical medicine medicine Humans Cumulative incidence Radiation Injuries Urinary Tract Survival rate Aged Aged 80 and over business.industry Prostatic Neoplasms Radiotherapy Dosage General Medicine Middle Aged Prostate-Specific Antigen medicine.disease Confidence interval Radiation therapy Gastrointestinal Tract Prostate-specific antigen Treatment Outcome Oncology 030220 oncology & carcinogenesis Toxicity Radiotherapy Intensity-Modulated Radiotherapy Conformal business Radiotherapy Image-Guided |
| Zdroj: | Anticancer research. 38(1) |
| ISSN: | 1791-7530 |
| Popis: | Background/aim We experienced an unexpected high incidence of gastrointestinal (GI) toxicity in patients undergoing image-guided intensity-modulated radiotherapy (IG-IMRT) using helical tomotherapy in our initial 2.2 Gy/fraction schedule for prostate cancer; hence, a dose-reduction trial from 2.2 Gy to 2 Gy/fraction was conducted using modified planning target volume (PTV) contouring. Patients and methods We compared 130 patients treated using 2.2 Gy/fraction (Group A) and 144 treated using the 2 Gy/fraction (Group B) with modified PTV (excluding rectal volume) with a median follow-up period of 62 months. Prescribed dose was 72.6-74.8 Gy in 33-34 fractions (Group A) and 72-74 Gy in 36-37 fractions (Group B). Results Patients in Group B had a reduced rectal and bladder V10-V70 and were irradiated at the maximal dose. Their cumulative incidence of grade ≤2 GI toxicity at 5 years improved from 10.1% [95% confidence interval (CI), 4.9-15.3%] to 1.4% (0-3.3%). Grade 2≤ urinary toxicity also decreased from 5.5% (1.5-9.4%) in Group A to 1.4% (0-3.3%, p=0.0167) in Group B. The biochemical failure-free 5-year survival rate was 89.1% (95%CI=83.6-95.4%) and 87.5% (82.0-92.9%, p=0.75) in groups A and B, respectively. Conclusion The reduced dose fraction schedule decreased the incidence of late GI toxicity without compromising prostate-specific antigen control. Careful target volume definition and fraction size are important even for IG-IMRT. |
| Databáze: | OpenAIRE |
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