A new indication of sildenafil in medicine: hypoxic cell sensitizer for penile cancer.

PURPOSE: To evaluate the feasibility and results of sildenafil used as radiosensitizer by causing penile vasodilatation and reducing tumor hypoxia in radical radiotherapy for penile cancer. MATERIALS AND METHODS: Three men with histopathologic diagnosis of squamous carcinoma of penis were treated with radical external radiotherapy with concomitant sildenafil. Acute and late adverse events were noted according to RTOG toxicity criteria. Response to radiotherapy, as well as disease-free and overall survivals, was evaluated. RESULTS: All three patients achieved tumescence, completed the treatment and achieved complete response. One patient had recurrence at 10 months and died of the disease after 23 months from starting the treatment. Other two patients are disease-free and alive at 48 and 53 months respectively. No excess acute or late adverse event was observed. CONCLUSION: Sildenafil may act as radiosensitizer by causing penile vasodilatation and reducing hypoxia. Larger controlled studies are required to validate the hypothesis.

T2 weighted MRI in assessment of volume changes during radiotherapy of high grade gliomas.

AIM: To determine whether any changes in gross tumor volume occur between pre treatment MRI and week 5 MRI in high grade gliomas treated by conformal radiotherapy. METHODS AND MATERIALS: Between July 2003-July 2005, 17 patients with WHO grades 3 and 4 malignant gliomas treated with conformal radiotherapy to a total dose of 60 Gy were included in this retrospective study. All patients had undergone T2 weighted MRI a day before treatment and then again at end of week 5 of treatment for definition of initial and boost fields respectively. Gross tumor volumes were delineated on the two MRI's of each patient and the differences were noted. Two patients with multifocal disease were excluded from the final analysis. RESULTS: Of the 15 patients with unifocal disease, 12/15 cases (80%) showed a reduction in tumor volumes (median 54.85 cc). Of these, 4/15 (26.6%) cases (two each of grade 3 and grade 4 gliomas) had an objective reduction in GTV (> or = 50%) and 3/15 (20%) cases (two of grade 4 and one of grade 3 gliomas) demonstrated an increase in tumor volume (median 14 cc). CONCLUSIONS: This study has shown that a change in gross tumor volume occurred in almost all patients on week 5 MRI. The likelihood of treatment success would appear to be decreased if the tumour is not within the treatment field and hence it may be worthwhile to do a mid treatment MRI for definition of boost volumes especially in dose escalation trials employing highly conformal radiotherapy fields.

Sanazole as a sensitizer of hypoxic cells with radical radiation in the treatment of advanced cancer of cervix an Indian experience.

AK-2123, is a nitrotriazole with a potential to sensitize hypoxic tissue to radiation. Cancer of cervix in advanced stages are predominantly treated with radiation. These are the tumours which harbour a large hypoxic core. This is an Indian experience of the multicentric trial. Patients were randomized to control and AK-2123 arm. 49 patients were randomized to each group. Patients received external radiation with telecobalt to a dose of 50 Gy in five weeks. Those in the study arm received 600 mg/m2, on alternate days. The patients were further treated with intracavitory radiation a dose of 20 Gy. The total dose of 70 Gy was achieved. Patients in the study arm had a complete response of 71.43% (35 of 49) while only 21 of 49 (42.86%) responded in the control group. The overall survival at two years was 72.2% for the study group and 32.43% for control. Neuropathy, a drug related toxicity was transient except, in one patient, which has persisted. AK-2123, has shown significant radiation sensitizing potential.