Kim, Seungwon

This phase II trial of transoral surgery (TOS) with deintensified postoperative management in human papillomavirus (HPV)–associated oropharynx cancer (OPC) enrolled patients with resectable cT1-2 stage III/IV American Joint Committee on Cancer (AJCC) seventh edition p16+ OPC without matted neck nodes. Those with clear margins, 0-1 + nodes (LN), and no extranodal extension (ENE) were observed (arm A); those with clear margins, 2-4 + LN, or ENE ≤1 mm were randomly assigned to 50 Gy (arm B) or 60 Gy (arm C); and those with involved margins, >4 + LN, or >1 mm ENE received weekly cisplatin and 60-66 Gy (arm D). Among 359 evaluable patients, the 54-month progression-free (PFS) and overall survival (OS) were 90.6% (90% CI, 87.2% to 93.1%) and 95.3% (93.0% to 96.9%), respectively. The 54-month PFS by arm was A 93.2% (79.6% to 97.8%; all four recurrences among N1 patients), B 94.9% (89.7% to 97.5%), C 90.2% (82.7% to 94.6%), and D 85.5% (77.5% to 90.8%). The 54-month OS by arm was A 97.1% (85.7% to 99.4%), B 97.9% (93.5% to 99.3%), C 95.1% (90.1% to 97.6%), and D 92.5% (86.9% to 95.7%). PFS or OS did not differ by primary site or smoking history. TOS and neck dissection with deintensified postoperative management results in outstanding 54-month PFS and OS. Among patients with favorable pathologic characteristics, those with N1 disease are at risk of late recurrence without radiation.

6009 Background: E3311 is a phase II trial of TOS by credentialed surgeons with pathology-driven deintensified post-operative management in HPV+ OPC. Intermediate risk patients were randomized between standard and reduced dose radiation. We present mature outcome data, at median follow up of 52.4 months (m). Methods: Patients were eligible who had resectable cT1-2 stage III/IV AJCC7 p16+ OPC without matted neck nodes. Those with clear margins, 0-1 + nodes (LN), and no extranodal extension (ENE) were observed (Arm A, N=38); those with clear margins, 2-4 + LN, or ENE ≤1mm were randomized to 50Gy (Arm B, N=100) or 60Gy (Arm C, N=108); those with involved margins, >4 + LN, or >1mm ENE received weekly cisplatin 40 mg/m2 and 60-66Gy (Arm D, N=113). Progression-free survival (PFS) and overall survival (OS) were estimated by the Kaplan-Meier method and compared using a log-rank test, stratified by arm for comparisons of primary site and smoking history. Results: Among 359 evaluable patients, 54-m PFS and OS were 90.6% (90% CI: 87.2%, 93.1%) and 95.3% (90% CI: 93.0%, 96.9%). 54-m PFS by arm was: A 93.2% (90% CI: 79.6%, 97.8%); B 94.9% (90% CI: 89.7%, 97.5%); C 90.2% (90% CI: 82.7%, 94.6%) and D 85.5% (90% CI: 77.5%, 90.8%). 54-m OS by arm was: A 97.1% (90% CI: 85.7%, 99.4%); B 97.9% (90% CI: 93.5%, 99.3%), C 95.1% (90% CI: 90.1%, 97.6%) and D 92.5% (90% CI: 86.9%, 95.7%). Among patients in Arm A, 11 had N0 and 27 N1 stage. Median Arm A lymph node yield (LNY) was 29 (11 to 91 LN) and did not differ for patients with/without recurrence (p=0.83). All Arm A recurrences were in N1 patients: 1 at 18 m and 3 at > 40 m. No significant difference in PFS or OS was observed by prescribed radiation dose for intermediate risk patients (Arm B vs. C). Outcome did not differ by primary site of tonsil vs. other OPC (oOPC): 54-m PFS Tonsil 89.3% (90% CI: 84.9%, 92.5%) vs. oOPC 92.9% (90% CI: 87.0%, 96.2%), p=0.28, and 54-m OS Tonsil 94.6% (90% CI: 91.5%, 96.6%) vs oOPC 96.6% (90% CI: 92.4%, 98.5%), p=0.35. Smoking history also did not impact outcome. 54-m PFS was 89.9% (90% CI: 85.9%, 92.9%) for those with ≤10 pack-years (PY) tobacco exposure and 91.7% (90% CI: 83.9%, 95.9%) for those with >10 PY. Conclusions: TOS, neck dissection with deintensified risk-based post-operative management results in outstanding 54-m PFS and OS across all subsites of T1-2 p16+ OPC, irrespective of smoking history. Late recurrence is not increased when post-operative radiation is reduced from 60 to 50Gy for intermediate risk patients. Pathologic >1mm ENE (N=87), involved margin (N=12) or >4 involved LN (N=30) accurately identify patients at increased recurrence risk and outcomes were favorable among such patients. Among patients with favorable pathologic characteristics, a subset with N1 disease are at risk for late recurrence and further characterization of these patients is warranted. Clinical trial information: NCT01898494 .

6036 Background: E3311 is a phase II randomized study of intermediate risk HPV+ OPC patients who underwent TOS by credentialed surgeons and were then treated by pathology-guided, deintensified post-operative treatment. Recent retrospective population data suggest that time to post-operative radiotherapy (PORT) > 6 weeks is associated with worse progression-free survival (PFS). Methods: We retrospectively analyzed demographics, pathologic characteristics, and oncologic outcomes in E3311 by time to initiation of PORT (short vs long, exploring both 6 and 7 weeks postop as the cutpoint). Binary and categorical variables were compared using a chi-square test (or a Fisher’s exact test for small sample sizes). Ordinal variables were compared using a Wilcoxon rank sum test. PFS and overall survival (OS) were estimated using the Kaplan-Meier method and compared using a log-rank test, which was stratified by intermediate- (Arms B/C) vs high-risk (Arm D). Results: Among 321 evaluable patients, the median time to initiation of PORT was 5.1 weeks (range 0.7-15.7); 5.0 (0.7-15.7) for Arm B, 5.1 (2.4-7.0) for Arm C, 5.6 (3.6-7.9) for Arm D. No significant difference in PFS or OS was observed whether PORT commenced by 6 or 7 weeks postoperatively, compared with longer time to initiation of PORT (p = 0.62 and 0.65, p = 0.30 and p = 0.41, respectively). 3-yr PFS rates were 93.5% (95% CI: 89.4%, 96.0%) among those treated ≤6 weeks, and 91.2% (95% CI: 81.4%, 95.9%) among those treated > 6 weeks; 3-yr OS rates were 96.1% (95% CI: 92.7%, 98.0%) among those treated ≤6 weeks, and 94.1% (95% CI: 84.9%, 97.8%) among those treated > 6 weeks. No significant differences in outcomes were observed between intermediate risk treatment arms (deintensified (50Gy) or standard dose (60Gy) RT). Additional demographic and pathologic characteristics, including primary site, margin status, histologic grade, stage, and extranodal extension were not significantly different between those with short vs long time to PORT, whether 6 or 7 weeks was used as the cutpoint. There were more T2 tumors in those treated > 7 weeks postop (84% vs. 49%, p = 0.007). PS = 1 patients were more numerous among those with shorter time to PORT (10% vs 0%, with the 7 week cutpoint). Conclusions: In contrast to retrospective NCDB data, intermediate- and high-risk HPV+ OPC patients enrolled on E3311 had favorable 3-yr PFS and OS rates that were not significantly worse when adjuvant therapy was started > 6 wks or > 7wks. These results argue against a survival advantage for initiation of PORT within 6 or 7 weeks for early-stage HPV+ OPC managed with high-quality transoral resection. The optimal time window to initiate PORT in HPV+ OPC patients remains to be determined. Clinical trial information: NCT01898494 .

ObjectiveThe American Joint Committee on Cancer (AJCC) 8th edition introduced distinct clinical and pathological staging paradigms for human papilloma virus positive (HPV+) oropharyngeal squamous cell carcinoma (OPSCC). Treatment planning for OPSCC often utilizes positron emission tomography/computed tomography (PET/CT) to assess clinical stage. We hypothesize that PET/CT will accurately predict final pathologic AJCC 8th edition staging in patients with HPV+ OPSCC.MethodsAll patients with primary HPV+ OPSCC with preoperative PET/CT who underwent transoral robotic surgery and neck dissection between 2011 and 2017 were identified. Data were collected via chart review. Two neuroradiologists performed blinded re‐evaluation of all scans. Primary tumor size and cervical nodal disease characteristics were recorded and TNM staging was extrapolated. Cohen's kappa statistic was used to assess interrater reliability. Test for symmetry was performed to analyze discordance between radiologic and pathologic staging.ResultsForty‐nine patients met inclusion criteria. Interrater reliability was substantial between radiologists for nodal (N) and overall staging (OS) (κ = 0.715 and 0.715). Radiologist A review resulted in identical OS for 67% of patients, overstaging for 31%, and understaging for 2%. Radiologist B review resulted in 61% identical OS, 39% overstaging, and 0% understaging. In misclassified cases, the test of symmetry shows strong bias toward overstaging N stage and OS (P < .001). Radiologic interpretation of extracapsular extension showed poor interrater reliability (κ = 0.403) and poor accuracy.ConclusionPET/CT predicts a higher nodal and overall stage than pathologic staging. PET/CT should not be relied upon for initial tumor staging, as increased FDG uptake is not specific for nodal metastases. PET/CT is shown to be a poor predictor of ECE.Level of Evidence4 Laryngoscope, 131:1535–1541, 2021