Postoperative chemoradiotherapy vs. preoperative chemoradiotherapy for locally advanced (operable) gastric cancer: clarifying the role and technique of radiotherapy.
Bibliographic record
Abstract
BACKGROUND: Worldwide, almost one million new cases of stomach cancer were diagnosed in 2012, making it the fifth most common cancer, and the third leading cause of cancer deaths. The current tumor node metastasis (TNM) staging system represents a consensus between the East and the West, and will serve as a strong foundation upon which to build future evidence. In this review article, we first discuss the definition and optimal surgery for locally advanced gastric cancer, followed by the general principles when considering a pre vs. postoperative radiotherapy (RT) strategy. We then provide a synthesis of the existing randomized trial evidence in an attempt clarify the role of pre and postoperative RT in the management of locally advanced gastric cancer. METHODS: A Medline search 1966-Jun 2014 was undertaken. Randomized trials including patients with locally advanced gastric cancer (using established definitions), comparing RT [with or without chemotherapy (CT)], with surgery alone or other treatment modalities were included. Systematic reviews and evidence based practice guidelines that include this body of primary studies were preferentially discussed. Medline, Cochrane Library, Clinicaltrial.gov, Guidelines Clearinghouse were searched. RESULTS: Sixteen randomized trials, three systematic reviews and one practice guideline were included as the evidence base. In this group of studies, two reports compared postoperative chemoradiotherapy (CRT) with surgery alone. Driven predominantly by INT0116, they established the role of postoperative CRT to provide a survival benefit in a patient group that underwent surgery with predominantly D0-1 dissections. Preoperative RT (four studies) showed promise for survival benefit but the risks of bias in these trials were high. Postoperative CRT compared with CT alone (eight trials) showed no survival benefit with the addition of radiation although some evidence of activity can be observed with improved local regional control. CONCLUSIONS AND FUTURE DIRECTIONS: Technical expertise to enable the delivery of high quality RT to complex target volumes as is required in gastric cancer, and surgical standards to ensure the delivery of high quality surgery, have matured in recent years. Six trials with large sample sizes are currently ongoing to better define the role of preoperative CRT (two studies) and postoperative CRT (four studies), when used in conjunction with high quality surgery and RT, and contemporary CT regimens. The moderate likelihood of locoregional recurrences and the favorable therapeutic ratio with using RT preoperatively in other settings, provide optimism that preoperative CRT would have a pivotal role to play in locally advanced gastric cancer. Active accrual into ongoing trials is strongly encouraged.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.004 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".