Weekly paclitaxel (P) with concurrent external beam radiation (EBRT) and androgen deprivation therapy (ADT) in high-risk prostate cancer (PC) patients with or without prior prostatectomy (RP)

5122

Background: EBRT with ADT (4 mos to 2–3 yrs) is standard treatment for high risk PC. In this trial, we evaluated weekly P given concurrently with EBRT and ADT in high risk PC. Methods: For pts undergoing RP, high risk was defined as: pT3 and/or pN+, M0, and/or rising PSA (> 0.5) post RP. For pts not undergoing RP (i.e. locally advanced PC [LAPC]) high risk included: cT2b-4N0, N+, M0; bGS 8–10; bGS ≥ 7 + PSA ≥ 10 but ≤ 150; and/or PSA ≥ 20 but ≤ 150. Treatment included ADT (4 or 24 mos, preplanned based on clinical presentation), P (40, 50, or 60 mg/m2/wk) x 7 with EBRT, and whole pelvis EBRT 45 Gy with 19.8 Gy boost (total 64.8 Gy) to prostate bed in RP pts and 25.2 Gy boost (total 70.2 Gy) to prostate in LAPC pts. Results: Between October 1999 and December 2006, 59 pts (29 W, 28 AA) were enrolled (n = 29 LAPC, n = 30 RP); median age 67 yrs, median PSA at trial entry 5.9 (27.5 LAPC, 1.6 RP), median GS 8. Pts were enrolled at different weekly doses of P: 40 mg/m2 n = 10 pts; 50 mg/m2 n = 31 pts; 60 mg/m2 n = 18 pts. ADT for 4 mos was given in 29 pts and for 24 mos in 30 pts. At 40 mg/m2 67/70 (96%), 50 mg/m2 202/217 (93%), and 60 mg/m2 98/126 (78%) planned doses of P were given. There were no acute grade 4 toxicities. Most common grade 3 toxicities were diarrhea 15%, urinary urgency or incontinence 10%, tenesmus 5%, and leukopenia 3%. Median duration of f/u was 75.3 mos, OS 78%, biochemical progression 24/59 (41%) pts, clinical progression 11/59 (19%) pts. Time to biochemical progression was similar between RP vs. LAPC (p = 0.17), between ADT 4 mos vs. 24 mos (p = 0.61), and between AA vs. W (p = 0.54). Conclusions: This trial establishes the feasibility of tri-modality therapy with ADT, EBRT and weekly paclitaxel in high risk PC, both in RP pts and in LAPC pts with intact prostate glands. The maximum tolerated dose of paclitaxel is 50 mg/m2 /wk when given weekly with concurrent radiation to the pelvis and hormone ablation.

No significant financial relationships to disclose.

Gamma Knife stereotactic radiosurgery in the treatment of brain metastases from breast cancer

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Background: Outcomes of gamma knife stereotactic radiosurgery (GK-SRS) for patients with brain metastases specifically from breast cancer have not been well-defined. This study was undertaken to report the long-term experience with GK-SRS in this subset of patients. Methods: From 1995 to 2005, 75 patients with 162 brain lesions were treated with GK-SRS at the University of Maryland Medical Center. Complete follow-up data were available in 65 patients. Additional whole brain radiation therapy (WBRT) was administered to 53 (81.5%) patients. The median WBRT dose was 36.75 Gy (30.0–45.0 Gy). The median number of lesions treated with GK-SRS was 2 (1–8 lesions). The median follow-up, age, and KPS were 7.2 months (0.4–75.7 months), 53.5 years (23–81 years), and 90 (40–100), respectively. The factors included in the univariate and multivariate analyses for overall survival (OS) and progression free survival (PFS) were age, Karnofsky Performance Status (KPS), tumor histology, estrogen receptor status, Her-2-neu status, number of intracranial lesions, and presence of systemic disease. Results: Median PFS and OS from GK-SRS were 5.3 months (0.4–33.2 months) and 8.1 months (0.4–75.7 months), respectively. The 6, 12, and 24 month actuarial PFS were 47.8%, 24.9%, and 9.6% respectively. The 6, 12, and 24 month actuarial OS were 60.7%, 39.1%, and 18.1% respectively. The tumor local control after WBRT and GK-SRS was 87.7%. Radiation necrosis was a complication in 10.8% of patients. Forty-seven (72.3%) patients had neurological symptoms prior to gamma knife treatment. Seven (14.9%) and 9 (19.1%) of these patients experienced symptom resolution and significant symptomatic improvement, respectively. Multivariate and univariate analysis did not reveal any of the prognostic factors in question to be significantly associated with OS nor PFS. Conclusions: This relatively large cohort of patients experienced poor survival outcomes despite aggressive therapy with WBRT and GK-SRS. However, GK-SRS can provide significant symptomatic relief, with acceptable complication rates. More research is required to improve the survival of breast cancer patients with intracranial metastases.

No significant financial relationships to disclose.

Comparative analyses of linac and Gamma Knife radiosurgery for trigeminal neuralgia treatments

Dedicated linac-based radiosurgery has been reported for trigeminal neuralgia treatments. In this study, we investigated the dose fall-off characteristics and setup error tolerance of linac-based radiosurgery as compared with standard Gamma Knife radiosurgery. In order to minimize the errors from different treatment planning calculations, consistent imaging registration, dose calculation and dose volume analysis methods were developed and implemented for both Gamma Knife and linac-based treatments. Intra-arc setup errors were incorporated into the treatment planning process of linac-based deliveries. The effects of intra-arc setup errors with increasing number of arcs were studied and benchmarked against Gamma Knife deliveries with and without plugging patterns. Our studies found equivalent dose fall-off properties between Gamma Knife and linac-based radiosurgery given a sufficient number of arcs (>7) and small intra-arc errors (<0.5 mm) were satisfied for linac-based deliveries. Increasing the number of arcs significantly decreased the variations in the dose fall-off curve at the low isodose region (e.g. from 40% to 10%) and also improved dose uniformity at the high isodose region (e.g. from 70% to 90%). As the number of arcs increased, the effects of intra-arc setup errors on the dose fall-off curves decreased. Increasing the number of arcs also reduced the integral dose to the distal normal brain tissues. In conclusion, linac-based radiosurgery produces equivalent dose fall-off characteristics to Gamma Knife radiosurgery with a high number of arcs. However, one must note the increased treatment time for a large number of arcs and isocentre accuracies.