First-ever Clinical Experience With Magnetic Resonance-based Lattice Radiotherapy for Treating Bulky Gynecological Tumors

Background/Aim: Bulky gynecological tumors are a rare entity of large primary tumors, for which only a limited range of therapeutic options is available. Among these, when surgical approach is deemed unsuitable based on comorbidities and/or technical feasibility, radiotherapy is administered at low doses with palliative intent only. Aggressive treatment of such large primary tumors might significantly prolong patient survival and improve their quality of life by effectively delaying tumor progression to extra-pelvic sites. Lattice radiotherapy is a type of Spatially Fractionated Radiation Therapy, specifically devoted to treat and debulk large tumor masses, which are not candidates for normofractionated homogeneous high-dose radiotherapy schedules due to potential harmful dose-volume effects. The aim of this case study was to report on the feasibility of a Magnetic Resonance Imaging-based Lattice approach. Case Report: Herein we report a case of a patient with a locally advanced uterine serous papillary carcinoma submitted to radical surgery and rapidly experiencing a painful large pelvic recurrence eroding the sacrum. The patient was submitted to Magnetic Resonance Imaging-based Lattice radiotherapy consisting of an Apparent Diffusion Coefficient Map-Based boost followed by a normofractionated radiotherapy course. The patient impressively developed an almost complete clinical response with a long-lasting symptom relief. Subsequently, the disease course was burdened by limited extra-and in-field recurrences amenable of re-irradiation as long as the cumulative radiation dose did not seriously threaten the tolerance of neighboring organs at risk (especially the bowel). The patient is still alive 20 months after Lattice radiotherapy delivery with no radiation -related toxicities. Conclusion: Magnetic resonance imaging (MRI)-based Lattice radiotherapy might be safe and effective for the treatment of inoperable bulky gynecological tumors.