Parameters Favorable to Intraprostatic Radiation Dose Escalation in Men With Localized Prostate Cancer

• Published in: International journal of radiation oncology, biology, physics Vol. 80; no. 2; pp. 614 - 620
• Main Authors: Housri, Nadine, M.D, Ning, Holly, Ph.D, Ondos, John, C.M.D, Choyke, Peter, M.D, Camphausen, Kevin, M.D, Citrin, Deborah, M.D, Arora, Barbara, M.S, Shankavaram, Uma, Ph.D, Kaushal, Aradhana, M.D
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.06.2011; Elsevier
• Subjects: Biological and medical sciences; BLADDER; BODY; CAT SCANNING; COMPUTERIZED TOMOGRAPHY; DIAGNOSTIC TECHNIQUES; DIGESTIVE SYSTEM; DISEASES; Dose escalation; DOSES; FRACTIONATED IRRADIATION; GASTROINTESTINAL TRACT; GLANDS; Gynecology. Andrology. Obstetrics; Hematology, Oncology and Palliative Medicine; Hip - anatomy & histology; Hip - diagnostic imaging; Humans; IMRT; INTESTINES; IRRADIATION; LARGE INTESTINE; Magnetic Resonance Imaging; Male; Male genital diseases; MALE GENITALS; Maximum Tolerated Dose; Medical sciences; MEDICINE; NEOPLASMS; Nephrology. Urinary tract diseases; NMR IMAGING; NUCLEAR MEDICINE; ORGANS; Organs at Risk - anatomy & histology; Organs at Risk - diagnostic imaging; PLANNING; PROSTATE; Prostate - diagnostic imaging; Prostate - pathology; Prostate cancer; Prostatic Neoplasms - diagnostic imaging; Prostatic Neoplasms - pathology; Prostatic Neoplasms - radiotherapy; RADIATION DOSES; Radiography; RADIOLOGY; RADIOLOGY AND NUCLEAR MEDICINE; RADIOTHERAPY; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; RECTUM; Rectum - anatomy & histology; Rectum - diagnostic imaging; THERAPY; TOMOGRAPHY; Treatment planning; Tumors; Tumors of the urinary system; Urinary Bladder - anatomy & histology; Urinary Bladder - diagnostic imaging; URINARY TRACT; Urinary tract. Prostate gland; IMRT; Dose escalation; Radiotherapy; Prostate cancer; Treatment planning; Human; Urinary system disease; Prostate disease; Male; Malignant tumor; Radiation dose; Intensity modulated radiotherapy; Treatment; Adult; Male genital diseases; Cancer
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2010.06.050

Purpose To identify , within the framework of a current Phase I trial, whether factors related to intraprostatic cancer lesions (IPLs) or individual patients predict the feasibility of high-dose intraprostatic irradiation. Methods and Materials Endorectal coil MRI scans of the prostate from 42 men were evaluated for dominant IPLs. The IPLs, prostate, and critical normal tissues were contoured. Intensity-modulated radiotherapy plans were generated with the goal of delivering 75.6 Gy in 1.8-Gy fractions to the prostate, with IPLs receiving a simultaneous integrated boost of 3.6 Gy per fraction to a total dose of 151.2 Gy, 200% of the prescribed dose and the highest dose cohort in our trial. Rectal and bladder dose constraints were consistent with those outlined in current Radiation Therapy Oncology Group protocols. Results Dominant IPLs were identified in 24 patients (57.1%). Simultaneous integrated boosts (SIB) to 200% of the prescribed dose were achieved in 12 of the 24 patients without violating dose constraints. Both the distance between the IPL and rectum and the hip-to-hip patient width on planning CT scans were associated with the feasibility to plan an SIB ( p = 0.002 and p = 0.0137, respectively). Conclusions On the basis of this small cohort, the distance between an intraprostatic lesion and the rectum most strongly predicted the ability to plan high-dose radiation to a dominant intraprostatic lesion. High-dose SIB planning seems possible for select intraprostatic lesions.