12 Gy gamma knife radiosurgical volume is a predictor for radiation necrosis in non-AVM intracranial tumors.

PURPOSE: To determine whether the 12-Gy radiosurgical volume (12-GyV) correlates with the development of postradiosurgical imaging changes suggestive of radiation necrosis in patients treated for non-arteriovenous malformation (non-AVM) intracranial tumors with gamma knife stereotactic radiosurgery (GKSRS). METHODS AND MATERIALS: A retrospective single-institution review of 129 patients with 198 separate non-AVM tumors was performed. Patients were followed with magnetic resonance imaging (MRI) and physical examinations at 3- to 6-month intervals. Patients who developed postradiosurgical MRI changes suggestive of radiation necrosis were labeled as having either symptomatic radiation necrosis (S-NEC) if they experienced any decline in neurologic examination associated with the imaging changes, or asymptomatic radiation necrosis (A-NEC) if they had a stable or improving neurologic examination. RESULTS: 12-GyV correlated with risk of S-NEC, which was 23% (for 12-GyV of 0-5 cc), 20% (5-10 cc), 54% (10-15 cc), and 57% (>15 cc). The risk of A-NEC did not significantly change with 12-GyV. Logistic regression analyses showed that the following factors were associated with the development of S-NEC: 12-GyV (p<0.01), occipital and temporal lesions (p<0.01), previous whole-brain radiotherapy (p=0.03), and male sex (p=0.03). Radiosurgical plan conformality did not correlate with the development of S-NEC. CONCLUSION: The risk of S-NEC, but not A-NEC after GKSRS for non-AVM tumors correlates with 12-GyV, and increases significantly for 12-GyV>0 cc.

Prostate-specific antigen response after definitive radiotherapy for Skene's gland adenocarcinoma resembling prostate adenocarcinoma.

OBJECTIVES: To assess prostate-specific antigen response after definitive radiotherapy in a patient with localized Skene's gland adenocarcinoma resembling prostate adenocarcinoma. MATERIALS AND METHODS: A 71-year-old patient was evaluated for a 2 year history of painless hematuria and found to have a localized Skene's gland adenocarcinoma resembling prostate adenocarcinoma with a pre-therapy PSA of 54.52 ng/ul. She elected to undergo definitive radiotherapy holding radical surgery for salvage. She received 73.8 Gy of intensity modulated radiotherapy in 41 fractions. Serum PSA, imaging, and cystoscopy were followed at 6 month intervals for 2.5 years. RESULTS: The PSA decreased to 0.65 ng/ul 32 months after treatment, her clinical symptoms resolved, and on imaging and exam she has no evidence of residual disease. The PSA half life was 6.16 months (r(2) = 0.97). CONCLUSIONS: For this rare tumor we show that PSA is a reliable marker for disease response and also show that definitive radiotherapy can be an option for organ and functional preservation in patients with localized disease. Cases of periurethral adenocarcinomas should be pathologically screened to assess if they are of Skene's gland origin, as our results suggest a radiotherapy treatment paradigm may be appropriate management in a select subgroup of women with periurethral adenocarcinoma.

Palliative radiotherapy: when is it worth it and when is it not?

Palliative radiotherapy has been prescribed since shortly after the discovery of the x-ray in the late 1800s, and it provides symptom relief that is successful, time-efficient, and cost-effective. Although palliative radiotherapy is worthwhile in a wide variety of clinical circumstances, there are situations where it is less worthwhile. We contrast the effective use of palliative radiotherapy with its ineffective use because of issues related to the patient, treatment, or health care system.