Treatment of astrocytoma grade III with Photofrin II as a radiosensitizer

Antitumor efficiency of contact radiotherapy in combination with a chlorin-based photosensitizer in experiment

Authors have studied the antitumor efficacy of contact radiation therapy (CRT) in combination with a chlorin-based photosensitizer (PS) in an experiment on laboratory animals with transplanted tumors. The experimental study was performed in 50 white outbred rats weighing 250±50 g. Subcutaneously transplanted Pliss lymphosarcoma (PLS) and alveolar liver cancer RS1 (RS1) were used as tumor models. Chlorinbased PS photolon (RUE «Belmedpreparaty», Republic Belarus) was injected intravenously at a dose of 2.5 mg/kg. The radiation sessions were carried out 2.5–4 hours (depending on the tumor model) after the administration of the PS using the device «microSelectron HDR V3 Digital» («Nucletron», Netherlands) with a 192-Ir radiation source in single focal doses 5 and 10 Gy. All laboratory animals (for PLS and RS1) were subdivided into 5 groups of 5 animals each: intact control, CRT 5 Gy, CRT 10 Gy, PS + CRT 5 Gy, PS + CRT 10 Gy. For the PLS tumor model – on the 14th day from the beginning of the experiment Vav. in groups were 26.31±5.81; 22.45±6.97; 18.99±4.86; 10.75±5.18 and 28.06±2.85 cm3, respectively (p˂0.05). The coefficients of tumor growth inhibition in the experimental groups were 14.67%, 27.82%, 59.14% and 6.65%, respectively. The frequency of complete tumor regressions 60 days after the start of the experiment was 0%, 20%, 20%, 60%, and 20%, respectively. On RS1 tumor model – on the 14th day from the beginning of the experiment Vav. in groups were 4.48±1.03; 0.80±0.21; 0.29±0.09; 0.19±0.07 and 0.32±0.08 cm3, respectively (p=0.009). The coefficients of tumor growth inhibition in the experimental groups were 82.14%, 93.53%, 95.76% and 92.86%, respectively. The frequency of complete tumor regressions 60 days after the start of the experiment was 0%, 0%, 20%, 0%, and 0%, respectively. Systemic administration of chlorin-based PS before the CRT session increases the antitumor efficacy of radiation therapy in animals with transplantable tumors of different histological structure and growth patterns. The data obtained indicate that further studies of the radiosensitizing properties of PS are promising.

5-Aminolevulinic acid radiodynamic therapy for treatment of high-grade gliomas: A systematic review

INTRODUCTION

Radiodynamic therapy (RDT) involves administration of a radiosensitizing agent and its subsequent activation by ionizing radiation for destruction of neoplastic cells.

MATERIALS AND METHODS

A comprehensive evaluation of the literature was performed to review the history of RDT using porphyrins for solid tumors, the cellular mechanisms of action, immunomodulatory effects, and both preclinical and clinical studies for use in high-grade gliomas (HGGs). This manuscript was prepared in accordance with the PRISMA guidelines.

RESULTS

A total of 271 articles were considered for initial review. After removal of duplicates, articles not unrelated to specific topic, and exclusion of commentary articles, a total of 11 articles were subject to full analysis that included in vivo, in vitro, and human studies. Porphyrins such as 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) selectively accumulate in neoplastic cells and are currently used for fluorescent-guided surgical resection and photodynamic therapy (PDT) of HGG and other brain tumors. 5-ALA is also shown to act as a radiosensitizer by increasing oxidative stress in neoplastic cell mitochondria and enhancing the host immune response. Postoperative radiation therapy is currently the standard of care for treatment of HGG.

CONCLUSION

RDT remains a promising adjuvant therapy for HGGs and requires further investigation. Clinical trials of 5-ALA RDT for HGG are needed to evaluate the optimum timing, dosing and effectiveness.

Treatment of cervix carcinoma FIGO IIIb with Photofrin II as a radiosensitizer: a case report

Cervical cancer is the fourth-most common type of cancer and cause of death in women. Human papilloma virus (HPV) infection is responsible for over 90% of cervical cancers. The recommended treatment is multidisciplinary, consisting of a combination of surgery, chemotherapy, and radiation therapy. The standard treatment in advanced stages, such as FIGO IIIb, is radio-chemotherapy with overall 5-year survival of 32%. Photofrin II has been demonstrated to serve as a specific and selective radiosensitizing agent in both in vitro and in vivo tumor models, admitted for radiation therapy. We describe a patient with advanced cervical carcinoma (squamous cell) who contacted us for further therapy in 2003. Staging included a gynecological examination, colonoscopy, explorative laparotomy, biopsy and pelvic MRI. The explorative laparotomy showed enlarged pelvic and para-aortal lymph nodes. The histologic examination described tumor infiltrated, positive lymph nodes (Stage FIGO IIIb). Contrary to recommendations, the patient refused standard treatment with a combination of chemotherapy and radiotherapy, but accepted a combined treatment of Photofrin II as a radiosensitizer and a radiotherapy procedure. She underwent irradiation with a 50.4 + 14 Gy boost with fractionation of 1.8 Gy day-1 for 5 days per week; the boost was given with 2 Gy fractions. She was injected with a single intravenous dose in a slow infusion (30 min) of 1 mg kg-1 of Photofrin II 24 h prior to radiation therapy. A localized relapse in the cervix appeared after 30 months, and was resected by hysterectomy. The patient is still alive with no evidence of disease after 15 years.