Opinions from the experts: exploring what prostate cancer patients should know about post-operative radiotherapy

The present study investigated health professionals' opinions about important questions that should be discussed with patients who may require post-prostatectomy radiotherapy. A 74-question survey was conducted among radiation oncologists, urologists, nurses, and radiation therapists involved in the care of prostate cancer patients. Survey questions covered six domains: understanding my situation and prostate cancer diagnosis, making a decision, radiotherapy: procedures involved, potential benefits, side effects, and my support network during radiation treatment. Respondents rated the importance of addressing these questions as either essential, important, no opinion, or avoid with a hypothetical post-prostatectomy case. The majority of questions were rated as either essential or important. There was disagreement between professions on essential questions, mostly between nurses and urologists in the side-effects domain. There was agreement between all professions regarding which questions should be avoided.

Intratumoral concentrations of imatinib after oral administration in patients with glioblastoma multiforme

Imatinib, an orally administered tyrosine kinase inhibitor of PDGF receptor, c-abl and c-kit, is currently in clinical trials to assess its efficacy in malignant gliomas. Although imatinib does not readily penetrate an intact blood-brain barrier (BBB), the extent to which it distributes into regions of high grade gliomas where the BBB is compromised has not been determined. Patients with recurrent high-grade gliomas for whom repeat surgical tumor debulking was clinically indicated received imatinib mesylate 600 mg orally once a day for seven days prior to surgery. Tissue samples were collected from different regions of the tumor and the approximate location of these samples was determined using frameless stereotactic neuronavigation. Plasma samples were obtained immediately before and after the resection. The concentration of imatinib in the plasma and tumor samples was determined using high performance liquid chromatography with mass spectrometric detection. Eleven tumor samples were obtained from three patients with recurrent glioblastoma multiforme. The median concentration of imatinib in these 11 tumor specimens was 1.34 microg/g (range 0.21-4.31 microg/g) and the median tumor-to-plasma ratio was 0.71 (range 0.28-3.03). These findings suggest that imatinib can reach intratumoral concentrations similar to those or higher than in plasma in regions of glioblastoma where the BBB is disrupted as indicated by contrast enhancement on magnetic resonance imaging.

Phase II study of imatinib in patients with recurrent gliomas of various histologies: a European Organisation for Research and Treatment of Cancer Brain Tumor Group Study

PURPOSE

To evaluate the safety and the efficacy of imatinib in recurrent malignant gliomas.

PATIENTS AND METHODS

This was a single-arm, phase II study. Eligible patients had recurrent glioma after prior radiotherapy with an enhancing lesion on magnetic resonance imaging. Three different histologic groups were studied: glioblastomas (GBM), pure/mixed (anaplastic) oligodendrogliomas (OD), and low-grade or anaplastic astrocytomas (A). Imatinib was started at a dose of 600 mg/d with dose escalation to 800 mg in case of no toxicity; during the trial this dose was increased to 800 mg/d with escalation to 1,000 mg/d. Trial design was one-stage Fleming; both an objective response and 6 months of progression-free survival (PFS) were considered a successful outcome to treatment.

RESULTS

A total of 112 patients (51 patients with GBM, 25 patients with A, and 36 patients with OD) were enrolled. Imatinib was in general well tolerated. The median number of cycles was 2.0 (range, 1 to 43 cycles). Five patients had an objective partial response, including three patients with GBM; all had 6 months of PFS. The 6-month PFS rate was 16% (95% CI, 8.0% to 34.0%) in GBM, 4.0% (95% CI, 0.3% to 15.0%) in OD, and 9% (95% CI, 2.0% to 25.0%) in A. The exposure to imatinib was significantly lower in patients using enzyme-inducing antiepileptic drugs. The presence of ABCG2 point mutations were not correlated with pharmacokinetic findings. No somatic activating mutations of KIT or platelet-derived growth factor receptor-A or -B were found.

CONCLUSION

In the dose range of 600 to 1,000 mg/d, single-agent imatinib is well tolerated but has limited antitumor activity in patients with recurrent gliomas.