Treatment of inoperable or metastatic paragangliomas and pheochromocytomas with peptide receptor radionuclide therapy using 177Lu-DOTATATE

OBJECTIVES

Inoperable or metastatic paragangliomas (PGLs) and malignant pheochromocytomas (PCCs) are rare tumours with limited options for systemic treatment. Aim of this study was to assess the safety and efficacy of the radiolabelled somatostatin analogue (177LutetiumDOTA0-Tyr3)octreotate (177Lu-DOTATATE) for the treatment of PGLs and PCCs.

METHODS

Patients with histologically proven inoperable or malignant PGLs and PCCs treated with 177Lu-DOTATATE at our centre were retrospectively analysed. Patients were treated with up to four cycles of 177Lu-DOTATATE with an intended dose of 7.4 Gb per cycle. Response was assessed with use of RECIST 1.1.

RESULTS

Thirty patients were included: 17 with parasympathetic, 10 with sympathetic PGLs and 3 with PCCs. Grade 3/4 subacute haematotoxicity occurred in 6 (20%) of patients. A reversible subacute adverse event due to cardiac failure following possible catecholamine release occurred in two patients. Best tumour response was partial response in 7 (23%) and stable disease in 20 (67%), whereas 3 (10%) patients had progressive disease. In 20 patients with baseline disease progression, tumour control was observed in 17 (85%); the median progression-free survival was 91 months in patients with parasympathetic PGLs, 13 months in patients with sympathetic PGLs and 10 months in patients with metastatic PCCs.

CONCLUSION

This study suggests that PRRT with 177Lu-DOTATATE is a safe and effective treatment option for patients with inoperable or malignant PGL and PCC.

Re-irradiation: outcome, cumulative dose and toxicity in patients retreated with stereotactic radiotherapy in the abdominal or pelvic region

The purpose of the present study was to explore the outcome, cumulative dose in tumor and organs at risk and toxicity after extra-cranial stereotactic re-irradiation. Twenty-seven patients were evaluated who had been re-irradiated with stereotactic body radiotherapy (SBRT) after conventional radiotherapy (CRT). The dose summation of the SBRT and CRT plans was done by dose point calculations accounting for fraction size by the linear-quadratic model. Efficacy and toxicity was scored by looking at the reduction in tumor size, pain and bleeding. Symptomatic response was observed in 96% of the patients. The median maximum SBRT dose to the tumor was 90 Gy₃ (range: 42-420 Gy₃). The median cumulative dose for the rectum, bowel and bladder resulted in 104 Gy₃, 98 Gy₃ and 113 Gy₃, respectively. No grades 5, 4 and 3 acute and late toxicity was observed. In conclusion: re-irradiation to the same region using extra-cranial stereotactic radiotherapy is feasible and resulted in a 96% symptomatic response with low toxicity.

Second re-irradiation: efficacy, dose and toxicity in patients who received three courses of radiotherapy with overlapping fields

PURPOSE

To explore the outcome, cumulative dose and toxicity in 23 patients after a third radiation treatment, with a partial or complete overlap of the previous two irradiated regions.

METHODS AND MATERIAL

The dose summation of the three radiation plans was made by the planning system. For patients treated with cyberknife or brachytherapy dose summation was done by dose point calculations. Efficacy and toxicity was scored by looking at the reduction of tumor, pain and bleeding.

RESULTS

Symptomatic response was observed in 81% and 73% of the patients after, respectively, the third and second radiation. The median cumulative maximum dose to the tumor and its regions was 133Gy(3) (range: 82-496Gy(3)). The median corrected cumulative dose for the rectum, bowel and bladder resulted in 91Gy(3), 73Gy(3) and 79Gy(3), respectively. Grade 3 acute skin toxicity was only seen in the third radiation course.

CONCLUSION

The constraints of 100Gy(3) for rectum, 90Gy(3) for bowel and 110Gy(3) for bladder are safe and can be used as guidelines in the decision for re-irradiation. Symptomatic relieve was seen in 81% of the patients with low grade 3 and no grade 4 acute and late toxicity.