Comprehensive Quantitative Evaluation of Variability in Magnetic Resonance-Guided Delineation of Oropharyngeal Gross Tumor Volumes and High-Risk Clinical Target Volumes: An R-IDEAL Stage 0 Prospective Study.

PURPOSE: Tumor and target volume manual delineation remains a challenging task in head and neck cancer radiation therapy. The purpose of this study was to conduct a multi-institutional evaluation of manual delineations of gross tumor volume (GTV), high-risk clinical target volume (CTV), parotids, and submandibular glands on treatment simulation magnetic resonance scans of patients with oropharyngeal cancer. METHODS AND MATERIALS: We retrospectively collected pretreatment T1-weighted, T1-weighted with gadolinium contrast, and T2-weighted magnetic resonance imaging scans for 4 patients with oropharyngeal cancer under an institution review board-approved protocol. We provided the scans to 26 radiation oncologists from 7 international cancer centers that participated in this delineation study. We also provide the patients' clinical history and physical examination findings, along with a medical photographic image and radiologic results. We used both the Simultaneous Truth and Performance Level Estimation algorithm and pair-wise comparisons of the contours, using overlap/distance metrics. Lastly, to assess experience and CTV delineation institutional practices, we had participants complete a brief questionnaire. RESULTS: Large variability was measured between observers' delineations for GTVs and CTVs. The mean Dice similarity coefficient values across all physicians' delineations for GTVp, GTVn, CTVp, and CTVn were 0.77, 0.67, 0.77, and 0.69, respectively, for Simultaneous Truth and Performance Level Estimation algorithm comparison, and 0.67, 0.60, 0.67, and 0.58, respectively, for pair-wise analysis. Normal tissue contours were defined more consistently when considering overlap/distance metrics. The median radiation oncology clinical experience was 7 years. The median experience delineating on magnetic resonance imaging was 3.5 years. The GTV-to-CTV margin used was 10 mm for 6 of 7 participant institutions. One institution used 8 mm, and 3 participants (from 3 different institutions) used a margin of 5 mm. CONCLUSIONS: The data from this study suggests that appropriate guidelines, contouring quality assurance sessions, and training are still needed for the adoption of magnetic resonance-based treatment planning for head and neck cancers. Such efforts should play a critical role in reducing delineation variation and ensure standardization of target design across clinical practices.

Inguinal lymph node recurrence in the untreated groin of patients with anal carcinoma.

BACKGROUND: Inguinal lymph node metastasis is predictive of locoregional recurrence and poor overall survival in anal carcinoma. Metachronous lymph node metastasis occurs in 10% of all anal cancer patients, but multiple studies have shown that the benefit of elective irradiation of the groin depends on T-stage, and the toxicity of groin irradiation must not be underestimated. OBJECTIVE: To analyze the inguinal recurrence rates among patients with anal carcinoma (T1-4, N0-1) who did not receive elective irradiation therapy to the groin and to determine predictors of inguinal recurrence. DESIGN: Data on 119 patients treated between 1987 and 2005 were retrospectively analyzed. Patients were treated with 3-dimensional radiotherapy. The median dose was 60 Gy. During radiotherapy, 108 patients also received chemotherapy (5-fluorouracil and mitomycin-C). RESULTS: AJCC staging showed a distribution of 21 T1 (18%), 58 T2 (49%), 27 T3 (23%), 13 T4 (11%), 101 N0 (85%) and 18 N1 (15%) tumors. The median follow up was 65 months (range, 1-240 months). The 5-year inguinal recurrence rate was 0% for T1, 10% for T2, 21% for T3 and 19% for T4 tumors (p = 0.034). T2 tumors of the perianal skin and the anal canal had 5-year inguinal recurrence rates of 12% and 8%, respectively. The 5-year inguinal recurrence rate was 21% for tumors ≥4 cm vs. 2% for tumors <4 cm in size (p = 0.003). LIMITATIONS: Eleven patients did not receive chemotherapy. CONCLUSIONS: Elective irradiation of the groin should be considered for local control in patients (N0-N1) with T2 tumors ≥4 cm in size and/or located in the perianal skin, and in all patients with T3 and T4 tumors.