Fractionated Proton Beam Therapy for Acoustic Neuromas: Tumor Control and Hearing Preservation.

PURPOSE: This prospective cohort evaluated patients with acoustic neuroma treated with proton irradiation at Loma Linda University Medical Center. A dose of 50.4 Gy in 28 fractions was given to improve hearing preservation while maintaining tumor control. PATIENTS AND METHODS: Ninety-five patients were treated from March 1991 to March 2008. Fractionated proton radiotherapy at daily doses of 1.8 Gy was employed. Patients were treated to 1 of 3 total doses: 59.4 Gy, used initially for patients without serviceable hearing; 54 Gy, used for patients with serviceable hearing through October 2000; and 50.4 Gy used since 2001 for patients with serviceable hearing. Survival and local control were calculated using the Kaplan-Meier method. Logistic regression analysis was preformed comparing dose, tumor size, and tumor location with hearing preservation. RESULTS: Ninety-four patients were assessable; the median follow-up was 64 months. Five-year local control rates for the 59.4 Gy, 54 Gy, and 50.4 Gy groups were 95%, 97%, and 92%, respectively (P = .80); the overall 10-year actuarial control rate was 90%. Cranial nerve injuries occurred in <5% in all groups. Four-year actuarial rates of hearing preservation were maintained in 44% of patients treated with 54 Gy and 64% treated with 50.4 Gy (P = .284). On multivariate analysis, initial tumor diameter (≤1.5 cm) was found to be a prognostic factor for maintaining serviceable hearing in both groups (P = .011). CONCLUSIONS: Fractionated proton therapy of 50.4 Gy offers excellent local control and minimal cranial nerve toxicities. Improved rates of hearing preservation that are comparable with radiosurgery were seen with 50.4 Gy compared with higher doses, although this did not reach significance. Maintaining hearing was found to be associated with smaller initial tumor size.

Proton radiation for treatment of cancer of the oropharynx: early experience at Loma Linda University Medical Center using a concomitant boost technique.

PURPOSE: To assess accelerated fractionation using photon and proton radiation to improve local control and reduce complications in treating locally advanced oropharyngeal cancer. METHODS AND MATERIALS: Twenty-nine patients with localized Stage II-IV oropharyngeal cancer received accelerated photon and proton radiation, 75.9 GyE in 45 fractions/5.5 weeks, to the primary disease, involved lymph nodes, and potential areas of subclinical spread. Follow-up ranged from 2 to 96 months. RESULTS: Five-year actuarial control for local disease was 88%, and for neck node disease, 96%; yielding a 84% locoregional control rate at 5 years. Four patients developed distant metastases. The 5-year actuarial locoregional control rate was 84%. The actuarial 2-year disease-free survival rate was 81%; at 5 years, it was 65%. All patients completed the prescribed treatment; though aggressive nutritional and anesthetic support was necessary. Late Grade 3 toxicity was seen in 3 patients. CONCLUSIONS: Protons used as a concomitant boost with photons effectively delivered an accelerated time-dose schedule to the cancer with a more tolerable schedule to surrounding normal tissues. Preliminary results reveal increased locoregional control without increased toxicity. Future studies must evaluate the optimum time-dose schedule.

Proton therapy for prostate cancer: the initial Loma Linda University experience.

PURPOSE: We analyzed results of conformal proton radiation therapy for localized prostate cancer, with emphasis on biochemical freedom from relapse. METHODS AND MATERIALS: Analyses were performed for 1255 patients treated between October 1991 and December 1997. Outcomes were measured on primarily in terms of biochemical relapse and toxicity. RESULTS: The overall biochemical disease-free survival rate was 73%, and was 90% in patients with initial PSA

Conformal proton radiation therapy for pediatric low-grade astrocytomas.

BACKGROUND: To evaluate the safety and efficacy of proton radiation therapy (PRT) for intracranial low-grade astrocytomas, the authors analyzed the first 27 pediatric patients treated at Loma Linda University Medical Center (LLUMC). PATIENTS AND METHOD: Between September 1991 and August 1997, 27 patients (13 female, 14 male) underwent fractionated proton radiation therapy for progressive or recurrent low-grade astrocytoma. Age at time of treatment ranged from 2 to 18 years (mean: 8.7 years). Tumors were located centrally (diencephalic) in 15 patients, in the cerebral and cerebellar hemispheres in seven patients, and in the brainstem in five patients. 25/27 patients (92%) were treated for progressive, unresectable, or residual disease following subtotal resection. Tissue diagnosis was available in 23/27 patients (85%). Four patients with optic pathway tumors were treated without histologic confirmation. Target doses between 50.4 and 63.0 CGE (Cobalt Gray Equivalent, mean: 55.2 CGE) were prescribed at 1.8 CGE per fraction, five treatments per week. RESULTS: At a mean follow-up period of 3.3 years (0.6-6.8 years), 6/27 patients experienced local failure (all located within the irradiated field), and 4/27 patients had died. By anatomic site these data translated into rates of local control and survival of 87% (13/15 patients) and 93% (14/15 patients) for central tumors, 71% (5/7 patients) and 86% (6/7 patients) for hemispheric tumors, and 60% (3/5 patients) and 60% (3/5 patients) for tumors located in the brainstem. Proton radiation therapy was generally well tolerated. All children with local control maintained their performance status. One child with associated neurofibromatosis, Type 1, developed Moyamoya disease. All six patients with optic pathway tumors and useful vision maintained or improved their visual status. CONCLUSIONS: This report on pediatric low-grade astrocytomas confirms proton radiation therapy as a safe and efficacious 3-D conformal treatment modality. Results are encouraging for central tumors as well as large optic pathway tumors, where dose conformity is of particular importance; yet it is difficult to achieve. Longer follow-up time is needed to fully evaluate the benefits of normal tissue sparing.