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Background: E3311 is a phase II randomized study which showed favorable outcomes among intermediate (INT) risk HPV+ OPC patients (pts) who underwent TOS followed by pathology-guided or adapted, deintensified adjuvant treatment. Among HPV+ pts treated with definitive chemoradiation, survival outcomes are worse among those who smoked > 10 pack years (pk-yrs). Methods: We retrospectively analyzed demographics, pathologic results, and efficacy outcomes from E3311 by smoking group (current (C) vs. former (F) and > 10 vs. ≤10 pk-yrs the latter a pre-specified stratification factor for INT patients). Binary and categorical variables were compared using a chi-square test (or Fishers exact test for small sample sizes). Ordinal variables were compared using a Wilcoxon rank sum test. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method and compared using a log-rank test. Results: Among 359 evaluable pts, performance status (PS) was significantly worse for pts with > 10 pk-yrs vs. ≤10 pk-yrs (15.4% vs. 7.9% with PS of 1, p = 0.034). Primary site, margin status, histologic grade, stage, and extranodal extension were not significantly different between the groups of > 10 vs. ≤10 pk-yrs. Smoking status (F vs. C) was available for 182 pts with a history of smoking. Slightly more C vs. F smokers had tonsil as primary site (79.5% vs. 65.0%, p = 0.09). Positive margins were significantly more frequent among C smokers (10.3% vs. 2.1%; p = 0.029). Overall, there were no significant differences in PFS (p = 0.55) or OS (p = 0.94), comparing those with > 10 vs. ≤10 pk-yrs, or comparing C vs. F smokers (p = 0.76, p = 0.82, respectively). Similarly, no significant differences were observed within the treatment arms. (Table 1) Conclusions: In this analysis of smoking status in E3311, INT risk HPV+ OPC pts who are C smokers or have a history of > 10 pk-yrs had favorable 3-yr PFS and OS rates that were not significantly worse than those with < 10 pk-yrs history. This data represents the first treatment approach for HPV+ OPC in which outcomes were not influenced by smoking status. Clinical trial information: NCT01898494.
| Smoking History(pk-yrs)
| N (pts)
| 3-yr PFS (%), 90% CI
| 3-yr OS (%), 90% CI
|
|---|
All evaluable pts, N = 356*
| > 10
< 10
| 104
252
| 95.5, (91.9%, 99.2%)
92.5, (89.7%, 95.3%)
| 96.8, (93.8%, 99.8%)
95.4, (93.1%, 97.6%)
| Arm A
| > 10
| 7
| 100%
| 100%
|
| ≤ 10
| 30
| 96, (90%, 100%)
| 96, (91%, 100%)
| Arm B
| > 10
| 33
| 97 (92%, 100%)
| 100
|
| ≤ 10
| 67
| 94 (89%, 99%)
| 99, (96%, 100%)
| Arm C
| > 10
| 30
| 95, (88%, 100%)
| 96, (90%, 100%)
|
| ≤ 10
| 78
| 93, (88%, 98%)
| 95, (90%, 99%)
| Arm D
| > 10
| 34
| 93, (86%, 100%)
| 93, (85%, 100%)
|
| ≤ 10
| 77
| 90, (84%, 96%)
| 93, (89%, 98%)
| Known Smoking status, N = 182
| Current (C)
Former (F)
| 39
143
| 93.8, (87.2%, 100%)
94.7, (91.6%, 98.0%)
| 94.3, (88.0%, 100%)
95.6, (92.7%, 98.5%)
|
|
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