A Dosimetric Comparison of Primary Chemoradiation Versus Postoperative Radiation for Locally Advanced Oropharyngeal Cancer
Bibliographic record
Abstract
Introduction Advanced-stage oropharyngeal cancer can be treated with primary chemoradiation (CRT) or primary surgery with adjuvant radiotherapy, both with similar survival outcomes. Though primary CRT prescribes a higher dose, adjuvant radiation requires irradiating the surgical bed, which may increase the high dose planned target volume (PTV). We hypothesize that the integral dose to the neck and dose to critical structures will be lower with primary CRT than adjuvant radiotherapy. Methods We selected the last 18 patients who underwent surgery and adjuvant radiotherapy at one institution between July 2015 and August 2016 with American Joint Committee on Cancer (AJCC) stage III or IVA oropharyngeal squamous cell cancer. Primary CRT treatment plans were created on the patients' preoperative computed tomography (CT) scans and prescribed 70 Gy in 33 fractions, while postoperative plans were prescribed 60 Gy in 30 fractions. The radiation doses received by organs at risk for each primary CRT plan were compared to the corresponding adjuvant radiation plan. Results Primary CRT plans had significantly smaller high dose PTV than adjuvant radiation plans (187.3 cc (95% CI 134.9-239.7) and 466.3 cc (95% CI 356.7-575.9), p<0.0001). The neck integral dose was lower in 14 of 18 plans using primary CRT, although this was not statistically significant (p=0.5375). The primary CRT plans had lower mean doses to ipsilateral (31.8 Gy (95% CI 27.5-36.0) vs 39.3 Gy (95% CI 35.4-43.1), p=0.0009)) and contralateral parotid glands (22.5 Gy (95% CI 22.1-22.8) vs 27.6 Gy (95% CI 23.4-31.8), p=0.0238) and larynx (20.7 Gy (95% CI 19.3-22.2) vs 40.2 Gy (95% CI 30.8-46.6), p<0.0001). Conclusion Primary CRT offered a decreased neck integral dose, though it was statistically insignificant. Primary CRT plans reduce mean dose to larynx and parotid glands in comparison to postoperative radiation, which may result in lower toxicities. Clinical trials comparing primary CRT and primary surgery are warranted to compare patient toxicities.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".