Comparison of investigator-delineated GTV in chemoradiotherapy (CRT) for locally advanced nonmetastatic pancreatic cancer (LANPC): Analysis of the pretrial test case for the SCALOP trial.

Background: SCALOP, a randomized, multicenter, phase II trial, tested efficacy/toxicity of gemcitabine (Gem) versus capecitabine (Cap) based CRT following 4 cycles of induction chemotherapy. 114 patients from 28 centers were registered and 75 patients had CRT. The RT Quality Assurance included a test case. GTVs outlined by investigators were evaluated by the chief investigator (CI). We report analysis of the test case.

Methods: the test case was LANPC of head of pancreas. The gold standard GTV (gsGTV) was outlined by the CI and trial radiologist. Protocol specified margins (GTV + 2cm sup-inf, 1.5 cm radial) were applied to generate the gold standard PTV (gsPTV). CT-DICOM dataset of the planning scan was sent to participating centers for tumor volume delineation by investigators and individualized feedback was provided by CI. CERR software was used to compare the investigator volumes (iGTV and iPTV) against the gold standard.

Results: volumes from 25 investigators were analyzed. The results are summarized below (Table). Slice-by-slice conformity indices and qualitative review showed that most variation occurred at the superior and inferior extremes of the tumor and a peri-tumoral node was frequently missed by investigators.

Conclusions: SCALOP is the first trial in LANPC to test investigator-delineated volumes using conformity indices, and has demonstrated considerable variation in iGTVs. Trial workshops and real-time central review of tumor outlines are proposed.

10.1200/jco.2013.31.4_suppl.230

1527-7755

Mukherjee, Somnath

b2ff936d-d068-48d5-9bb5-9f3431013b5b

Halle, Charlotte

02f4c653-dfc0-42d2-90e8-22605494e233

Spezi, Emiliano

2eab7319-0edc-4658-996d-9b00959b9124

Hurt, Chris

bf8b37a0-8f08-4b47-b3f3-6fc65f7ab87f

et al.

February 2013