5-year Actuarial Control Rate Research Articles

Fractionated Proton Radiotherapy for Benign Cavernous Sinus Meningiomas

To evaluate the efficacy of fractionated proton radiotherapy for a population of patients with benign cavernous sinus meningiomas. Between 1991 and 2002, 72 patients were treated at Loma Linda University Medical Center with proton therapy for cavernous sinus meningiomas. Fifty-one patients had biopsy or subtotal resection; 47 had World Health Organization grade 1 pathology. Twenty-one patients had no histologic verification. Twenty-two patients received primary proton therapy; 30 had 1 previous surgery; 20 had more than 1 surgery. The mean gross tumor volume was 27.6 cm(3); mean clinical target volume was 52.9 cm(3). Median total doses for patients with and without histologic verification were 59 and 57 Gy, respectively. Mean and median follow-up periods were 74 months. The overall 5-year actuarial control rate was 96%; the control rate was 99% in patients with grade 1 or absent histologic findings and 50% for those with atypical histology. All 21 patients who did not have histologic verification and 46 of 47 patients with histologic confirmation of grade 1 tumor demonstrated disease control at 5 years. Control rates for patients without previous surgery, 1 surgery, and 2 or more surgeries were 95%, 96%, and 95%, respectively. Fractionated proton radiotherapy for grade 1 cavernous sinus meningiomas achieves excellent control rates with minimal toxicities, regardless of surgical intervention or use of histologic diagnosis. Disease control for large lesions can be achieved by primary fractionated proton therapy.

Linear accelerator radiosurgery for vestibular schwannomas

Radiosurgery has become a popular treatment for small vestibular schwannomas (VSs). The aim of this study was to review an extensive, single-institution experience with linear accelerator (LINAC) radiosurgery for VSs. Between July 1988 and August 2005, 390 patients with VSs were treated with LINAC-based radiosurgery at the authors' institution. Patient and treatment variables were prospectively maintained in a computer database. Outcomes were tracked through periodic clinical examinations and annual scanning studies. Multivariate and actuarial statistics were used to analyze rates of local tumor control and complications, including facial and trigeminal neuropathies, after treatment. One- and 2-year actuarial control rates were both 98%, and the 5-year actuarial control rate was 90%. Only four patients (1%) required surgery for tumor growth. Seventeen patients (4.4%) reported facial weakness and 14 patients (3.6%) reported facial numbness after radiosurgery. The risk of these complications rose with increasing tumor volume or increasing radiosurgical dose to the tumor periphery. Since 1994, when doses were deliberately lowered to 1250 cGy, only two patients (0.7%) have experienced facial weakness and two (0.7%) have experienced facial numbness. Radiosurgery provides a safe and effective therapeutic alternative to surgery for small VSs.

The use of stereotactic radiosurgery in the management of meningiomas

This is a systematic review of a consecutive series of 309 meningiomas treated with gamma knife stereotactic radiosurgery between 1994 and 2000. There was an extreme selection bias towards lesions unfavourable for surgery, determined by the patients referred for treatment: 70% of tumours involved the skull base, 47% specifically the cavernous sinus: 15% of patients had multiple meningiomatosis or type 2 neurofibromatosis. Tumour histology was the main determinant of growth control (p < 0.001), the 5-year actuarial control rates being 87% for typical meningiomas, 49% for atypical tumours and 0% for malignant lesions. Complications from radiosurgery were rare, occurring in 3% of tumours, and were most frequently trigeminal and eye movement disturbances treating cavernous sinus meningiomas. Given the problems inherent in managing these tumours, radiosurgery is a valuable strategy and adjuvant treatment for these meningiomas.

Assessing the variability of outcome for patients treated with localized prostate irradiation using different definitions of biochemical control

Purpose : Biochemical control using serial posttreatment serum prostate specific antigen (PSA) levels is being increasingly used to assess treatment efficacy for localized prostate cancer. However, no standardized definition of biochemical contrl has been established. We reviewed our experience treating patients with localized prostate cancer and applied three different commonly used definitions of biochemical control to determine if differences in therapeutic outcome would be observed. Methods and Materials : Between January 1987 and December 1991, 480 patients with clinically localized prostate cancer received external beam irradiation (RT) using localized prostate fields at William Beaumont Hospital. The medial dose to the prostate was 66.6 Gy (range 57–70.4) using a four-field or arc technique. Pretreatment and posttreatment serum PSA levels were recorded. Over 86% (414 of 480) of patients had a pretreatment PSA level available. Three different definitions of biochemical control were increases of PSA were noted, the patient was scored a failure at the time of the first increase; (b) PSA nadir < 1.5 ng/ml within 1 year of treatment completion. After achieving nadir, if two consecutive increases of PSA were noted, the patient was scored a failure at the time of the first increase; (c) Posttreatment PSA nadir < 4 ng/ml without a time limit. Once the nadir was achieved, if it did not rise above normal the patient was considered to be biochemically controlled. Clinical local control was defined as no palpable prostate nodularity beyond 18 months, no new prostate nodularity, or a negative prostate biopsy. Results : Median follow-up was 48 months (range 3–112). Pretreatment PSA values were correlated with treatment outcome using the three definitions of biochemical control as well as clinical local control. Pretreatment PSA values were stratified into five groups (Group 1: PSA < 4; Group 2: PSA 4–10; Group 3: PSA 10–15; Group 4: PSA 15–20; and Group 5: PSA > 20), and 5-year actuarial rates of biochemical control were calculated using the three biochemical control and one clinical local control definitions. For Group 1, 5-year actuarial rates of biochemical control were 84%, 90%, 91%, and 906% for Definitions 1–3 and clinical local control, respectively. For Group 2, 5-year actuarial control rates were 45%, 54%, 74%, and 92% for the four definitions, respectively. For Group 3, 5-year actuarial control rates were 26%, 31%, 63%, and 100% for the four definitions, respectively. For Group 4, 5-year actuarial control rates were 24%, 24%, 50%, and 100% for the four definitions, respectively. Finally, for Group 5, 5-year actuarial control rates were 5%, 14%, 15%, and 89% for the four definitions, respectively. Depending on the definition used, statistically significant differences overall in outcome rates were observed. Differences between all four definitions for all pairwise comparisons ranged from 5 top 53% ( p < 0.001). Conclusion : When different definitions of biochemical control are used in assessing treatment outcome, significantly different rates of success are noted. Until a standardized definition of biochemical control is adopted, differences in treatment outcome cannot be meaningfully compared.