Influence of tumor cell proliferation and sex-hormone receptors on effectiveness of radiation therapy for dogs with incompletely resected meningiomas.

摘要

20 dogs with incompletely resected intracranial meningiomas were treated with 48 Gy of radiation 3 times weekly on an alternate-day schedule of 4 Gy/fraction for 4 weeks, using bilateral parallel-opposed fields. Tumour proliferative fraction measured by immunohistochemical detection of proliferating cell nuclear antigen (PFPCNA index) ranged from 10 to 42% (median, 24%). Progesterone receptor immunoreactivity was detected in 70% of tumours. Oestrogen receptor immunoreactivity was not detected. An inverse correlation was found between detection of progesterone receptors and the PFPCNA index. The overall 2-year progression-free survival (PFS) rate was 68%. The only prognostic factor that significantly affected PFS rate was the PFPCNA index. The 2-year PFS was 42% for tumours with a high PFPCNA index (value >=24%) and 91% for tumours with a low PFPCNA index (value <24%). Tumours with a high PFPCNA index were 9.1 times as likely to recur as were tumours with a low PFPCNA index. Prognostic value of thePFPCNA index suggests that duration of treatment and interval from surgery to start of irradiation may affect outcome. Loss of progesterone receptors in some tumours may be responsible for an increase in PFPCNA index and may indirectly affect prognosisafter radiation therapy.