{Reference Type}: Journal Article
{Title}: Retrospective observational studies in ultra-rare sarcomas: A consensus paper from the Connective Tissue Oncology Society (CTOS) community of experts on the minimum requirements for the evaluation of activity of systemic treatments.
{Author}: Stacchiotti S;Maria Frezza A;Demetri GD;Blay JY;Bajpai J;Baldi GG;Baldini EH;Benjamin RS;Bonvalot S;Bovée JVMG;Callegaro D;Casali PG;D'Angelo SP;Davis EJ;Dei Tos AP;Demicco EG;Desai J;Dileo P;Eriksson M;Gelderblom H;George S;Gladdy RA;Gounder MM;Gupta AA;Haas R;Hayes A;Hohenberger P;Jones KB;Jones RL;Kasper B;Kawai A;Kirsch DG;Kleinerman ES;Le Cesne A;Maestro R;Martin Broto J;Maki RG;Miah AB;Palmerini E;Patel SR;Raut CP;Razak ARA;Reed DR;Rutkowski P;Sanfilippo RG;Sbaraglia M;Schaefer IM;Strauss DC;Strauss SJ;Tap WD;Thomas DM;Trama A;Trent JC;van der Graaf WTA;van Houdt WJ;von Mehren M;Wilky BA;Fletcher CDM;Gronchi A;Miceli R;Wagner AJ;
{Journal}: Cancer Treat Rev
{Volume}: 110
{Issue}: 0
{Year}: Aug 2022 18
{Factor}: 13.608
{DOI}: 10.1016/j.ctrv.2022.102455
{Abstract}: <B>BACKGROUND: </B>In ultra-rare sarcomas (URS) the conduction of prospective, randomized trials is challenging. Data from retrospective observational studies (ROS) may represent the best evidence available. ROS implicit limitations led to poor acceptance by the scientific community and regulatory authorities. In this context, an expert panel from the Connective Tissue Oncology Society (CTOS), agreed on the need to establish a set of minimum requirements for conducting high-quality ROS on the activity of systemic therapies in URS.<BR><B>METHODS: </B>Representatives from > 25 worldwide sarcoma reference centres met in November 2020 and identified a list of topics summarizing the main issues encountered in ROS on URS. An online survey on these topics was distributed to the panel; results were summarized by descriptive statistics and discussed during a second meeting (November 2021).<BR><B>RESULTS: </B>Topics identified by the panel included the use of ROS results as external control data, the criteria for contributing centers selection, modalities for ensuring a correct pathological diagnosis and radiologic assessment, consistency of surveillance policies across centers, study end-points, risk of data duplication, results publication. Based on the answers to the survey (55 of 62 invited experts) and discussion the panel agreed on 18 statements summarizing principles of recommended practice.<BR><B>CONCLUSIONS: </B>These recommendations will be disseminated by CTOS across the sarcoma community and incorporated in future ROS on URS, to maximize their quality and favor their use as control data when results from prospective studies are unavailable. These recommendations could help the optimal conduction of ROS also in other rare tumors.