Session Item

To evaluate feasibility, toxicities and clinical response in Stage IV patients with bulky tumour treated with LATTICE technique. The aim of the present study, called LATTICE_01, is to deliver high doses of radiation to hypoxic areas within the gross tumour volumes (GTV). The goals of this innovative approach are to stimulate abscopal effect and to activate bystander effect on the nearby normoxic areas.     

From June 2020 to October 2021 we selected all metastatic patients with bulky tumour both unresectable and unsuitable to ablative radiotherapy in the experimental centers (G. Martino Messina University Hospital, REM Radiotherapy srl Viagrande, IOM Viagrande Foundation). Among these, we enrolled the patients who had a Karnofsky Performance Status (KPS) ≥ 60, a life expectancy major of six months and permissive clinical/biochemical parameters. 

Twenty-two patients (17 male and 5 female) with histological diagnosis of neoplastic and systemic disease were enrolled. The median age was 75 years (range 42-91); all patients had contrast-enhanced CT, 18F-PET/CT and in selected cases contrast-enhanced MRI.

The first therapy’s phase provided to deliver high radiation doses within bulky tumour using “balls of dose”, called VERTEX, positioned between hypoxic and normoxic tissue following a non-geometric model. The median total dose delivered on VERTEX was 15Gy (range 10-27Gy) in 1-5 fractions. In the second treatment phase, a median total dose of 30Gy (range 18 – 40,05Gy) was delivered on GTV ± Clinical Target Volume (CTV). 

With a median follow up of seven months (range 1-13 months) we recorded an 89% of clinical response (figure 1; 2). Particularly, 23% of the patients showed a complete response (CR) and in 63% of patients, a partial response (PR) has been observed. Stable disease (SD) and progression disease (PD) were 9% and 4.5% respectively. The toxicities records were poor: radiodermatitis G1 have been observed in the 36% of the patients, while no grade 3 toxicities were recorded.

The LATTICE_01 approach is feasible and well tolerated with encouraging results in terms of toxicities and overall response rate. These preliminary results seem to indicate that this kind of therapy could emerge as a therapeutic option in this setting of patients.