ESTRO 36 Abstract Book

S245 ESTRO 36 2017 _______________________________________________________________________________________________

11 CHU Timone, Bouches-du-Rhone, Marseille, France 12 Hôpital Universitaire Carémeau, Gard, Nimes, France 13 Centre Alexis Vautrin, Meurthe-et-Moselle, Nancy, France 14 Hopital Lariboisiere, Paris, Paris, France 15 CHU Hotel-Dieu, Puy-de-Dome, Clermont-Ferrand, France 16 CHU de Bordeaux- Hopital Pellegrin, Gironde, Bordeaux, France 17 CHU de Bordeaux- USMR, Gironde, Bordeaux, France Purpose or Objective The objective was to compare local excision (LE) and total mesorectal excision (TME) in patients with a good response after radiochemotherapy for low rectal cancer. Material and Methods Patients with T2-T3 low rectal carcinoma, maximum size 4 cm, received neoadjuvant radiochemotherapy. Good clinical responders (residual tumor ≤ 2 cm) were randomized between LE and TME. In the LE group, a completion TME was required if ypT2-3. The primary end point was a composite outcome including death, recurrence, morbidity and after-effects at 2 years. Secondary outcomes were pathologic response, 3-year local recurrence and survival. Results A hundred forty eight good clinical responders to radiochemotherapy were randomized, 3 were excluded and 145 were analyzed: 74 in the LE group and 71 in the TME group. In the LE group, 26 patients had a completion TME. At 2 years, significant events occurred in 56% in the LE group and 48% in the TME group (p=0.320). In intention- to-treat analysis, there was no difference between LE and TME in all components of the composite outcome. Per protocol analysis showed a lower morbidity (11%/21%/48%,p=0.001) and fewer after-effects (17%/29%/62%,p<0.001) according to type of surgery LE, TME and completion TME. Pathologic results showed a low rate of positive lymph nodes in ypT0-1 (0%) and ypTx/cN0 (2%). 3-year local recurrence (5%) and overall survival (92%) were similar between LE and TME groups. Conclusion LE is oncologically safe as compared to TME. Globally it is not superior to TME, due to a high rate of completion TME that increases morbidity and after-effects. A better patient selection removing unnecessary completion TME (ypT2/cN0) will improve the strategy. OC-0466 Brachytherapy for conservative treatment of penile carcinoma: prognostic factors and outcome A. Escande 1 , C. Haie-Meder 1 , R. Mazeron 1 , P. Castelnau- Marchand 1 , P. Maroun 1 , A. Cavalcanti 2 , F. Marsolat 1 , K. Doyeux 1 , R. De Crevoisier 3 , F. Martinetti 1 , I. Dumas 1 , E. Deutsch 1 , C. Chargary 1 1 Gustave Roussy Cancer Campus, Brachytherapy Unit- Radiation Oncology, Villejuif, France 2 Gustave Roussy Cancer Campus, Department of Surgery, Villejuif, France 3 Eugene Marquis Cancer Center, Radiation Oncology, Rennes, France THIS ABSTRACT FORMS PART OF THE MEDIA PROGRAMME AND WILL BE AVAILABLE ON THE DAY OF ITS PRESENTATION TO THE CONFERENCE. OC-0467 Investigating reporting-and-learning systems of Irish radiation therapy: Can standards be improved? K. Dowling 1 , C. Poole 1 , L. Mullaney 1 , S. Barrett 1 1 Trinity College Dublin, Discipline of Radiation Therapy, Dublin, Ireland Purpose or Objective Wide variation exists between event (incidents and near- misses) reporting-and-learning systems utilised in the field of radiation oncology. Due to the high potential for error

Conclusion A real-time 3D tumor motion monitoring method was established and validated in experiments and simulations using known Calypso-recorded liver tumor motion. The method is fully automatic and can be used for arbitrarily shaped fiducial markers in the thorax or abdomen on a conventional linac without additional time or hardware. The internal position estimation can also be performed for non-coplanar fields where there is no room to deploy the kV imaging system. OC-0465 Organ preservation for rectal cancer: the GRECCAR 2 randomized phase III trial V. Vendrely 1 , P. Rouanet 2 , J.J. Tuech 3 , H. Mosnier 4 , B. Lelong 5 , M. Rivoire 6 , J.L. Faucheron 7 , M. Jafari 8 , G. Portier 9 , B. Meunier 10 , B. Sastre 11 , M. Prudhomme 12 , F. Marchal 13 , M. Pocard 14 , D. Pezet 15 , A. Rullier 16 , J. Asselineau 17 , A. Doussau 17 , E. Rullier 1 1 CHU de Bordeaux, Gironde, Pessac, France 2 Institut Regional du Cancer Montpellier, Herault, Montpellier, France 3 CHU Charles Nicolle, Seine-Maritime, Rouen, France 4 Groupe Hospitalier Diaconesses Croix Saint-Simon, Paris, Paris, France 5 Département de Chirurgie Oncologique- Institut Paoli Calmette, Bouches-du-Rhone, Marseille, France 6 Département de Chirurgie Oncologique- Centre Léon Bérard, Rhone, Lyon, France 7 Service de Chirurgie Digestive- Hôpital A. Michallon, Isere, Grenoble, France 8 Centre Oscar Lambret, Nord, Lille, France 9 Hopital Purpan - Pavillon Dieulafoy, Haute-Garonne, Toulouse, France 10 CHU Pontchaillou, Ille-et-Vilaine, Rennes, France