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Purpose Evaluate efficacy and toxicity of hypofractionated stereotactic radiotherapy (HSRT) for patients treated for pituitary adenoma (PA) with an alternative HSRT escalating protocol delivering 35 Gy in 5 fractions. Material and methods From June 2007 to March 2017, 29 patients with pituitary adenoma were treated in Antoine Lacassagne Cancer Centre with an alternative HSRT protocol. Prescribed dose was 35 Gy in 5 fractions of 7 Gy. Radiographic responses were assessed by annual MRI. Hormone blood samples were evaluated each year after HSRT. Results A total of 29 patients aged between 23 and 86 years (median 54 years) were included. Twelve patients received HSRT for recurrent cases and 12 received postoperative adjuvant HSRT, 5 patients did not have surgery. After a median follow-up period of 47 months local control rate was 96%. One patient presented an out-field tumor regrowth 73 months after HSRT. The majority of PA were endocrine-active (18 patients, 62%). After HSRT, 8 patients (44%) presented complete response on initial secretion, 4 patients (23%) presented partial response on initial secretion. Four patients (14%) presented grade 2 or more acute radiation toxicities. One grade 4 visual disorder was observed for one patient. Conclusions HSRT delivering 35 Gy in 5 fractions represents a feasible treatment and shows promising results to reduce hormonal overproduction and to improve local control in PA.

The Papillon experience and the Lyon R96-02 trial have shown that contact X-ray brachytherapy of 50kV is efficient and safe to achieve long term local control and organ preservation for cT1 and early cT2-3 rectal cancers. The OPERA trial, using the Papillon 50™ machine, brings further support to this preservation strategy for selected T2T3ab lesions. Future trials using a contact X-ray boost will try to consolidate and enlarge its place in organ preservation for rectal cancers.

Contact X ray brachytherapy 50 kVp was initiated in the 1930s with the Siemens unit and popularized with the Philips unit in the 1950s. A renaissance was seen in the early 2000s with the Intrabeam™ unit for breast IORT. Presently the Papillon™ systems thanks to its high dose rate (> 10 Gy/mn) can be used to treat breast (IORT), skin, eyelid and rectal cancers. Future developments are expected to consolidate the place of contact radiotherapy as a safe and efficient treatment for accessible early tumors.