It is a multicenter prospective observational study including consecutive patients with esophageal tumor or rectum with indication for radiotherapy

The main objective of this study is to evaluate the feasibility of fiducial markers placement under EUS guidance. The evaluation criteria are:

• Success rate evaluation of the placement of two markers : one in the upper part of the tumor and one in the lower part. Success of the procedure will be evaluated by the endoscopist at the end of the procedure. Pictures of the markers will objectify the good placement of the markers.
• Complications (early within 24 hours and late complications) such as pain, bleeding, perforation, infection, migration of the markers
• The length of the procedure
• The costs (procedure, hospitalization)
• The clinical efficacy, by studying the decrease of the estimated target volume, the decrease of the dose delivered to the healthy tissue and the improvement of positioning of the irradiation beams by the radiotherapy technician
• The presence of the markers at the end of the radiotherapy

• Rational Cancers of the rectum and esophagus affect 15 000 and 4300 people per year in France (TNCD, the national digestive cancer thesaurus). Their prognosis remains bleak, particularly due to late diagnosis, with a 5-year survival rate of 10% for cancers of the esophagus and 55% at 5 years for rectal cancers (TNCD). When diagnosed at an advanced stage (> T2 or N +), treatment with radiotherapy +/- chemotherapy is indicated. The precise definition of macroscopic tumor volume in radiotherapy represents an important difficulty because it is based on endoscopic and imaging data obtained under conditions different from those used in the preparation of radiotherapy treatment. A better definition of the target tumor volume using radiopaque markers known as fiducial markers would be likely to improve the efficacy and tolerance of this treatment, or even to allow additional irradiation that would be targeted more precisely on the tumor.
• Objectives :

The main objective of this study is to evaluate the feasibility of fiducial markers placement under EUS guidance.

The secondary objectives are to evaluate :

• Complications (early within 24 hours and late complications) such as pain, bleeding, perforation, infection, migration of the markers
• The length of the procedure
• The costs (procedure, hospitalization)
• The clinical efficacy, by studying the decrease of the estimated target volume, the decrease of the dose delivered to the healthy tissue and the improvement of positioning of the irradiation beams by the radiotherapy technician
• The presence of the markers at the end of the radiotherapy primary and secondary • Research methodology It is a prospective multicenter study, 18 centers will participate. Forty patients are to include over a period of 24 months.

Inclusion Criteria:

• Patients > 18 years
• Patients presenting an oesophageal or a rectal tumor passable with a linear echoendoscope
• TP> 60% et Platelets > 50 000/mm3
• No anticoagulant treatment or antiagregants being taken other than aspirin in the five days preceding the EUS
• Patient affiliated to a social security scheme (payee or beneficiary)
• Patient who signed a free and informed consent

Exclusion Criteria:

• Patient < 18 years
• Pregnant Woman
• Tumor stenosis impassable by the linear echoendoscope
• Patient participation refusal
• Patient under legal protection regime (guardianship / curatorship)