Pathologic complete response to standard preoperative chemoradiation in patients with locally advanced rectal cancer.
Bibliographic record
Abstract
686 Background: Pathologic complete response (pCR) is associated with lower rates of recurrences and longer disease-free survival rates in locally advanced rectal cancer (LARC) patients. The purpose of this study was to evaluate clinical outcomes of neoadjuvant chemoradiation and pCR among these patients. Methods: A retrospective chart review was performed for all patients treated for LARC between August 2005 and May 2011 at St. Michael's Hospital, Toronto. Patients were stratified into pCR and no-pCR groups and compared with respect to tumor size, nodal status, and treatment characteristics. Descriptive statistics were calculated for all variables of interest. Chi-square and t-tests were conducted to test for associations between categorical and continuous variables respectively. Disease free survival was calculated as the time between diagnosis and recurrence date, censored at last follow up. Results: A total of 92 patient charts were reviewed; 21 patients had metastatic carcinoma and were excluded from analysis. 63.4% (45/71) were male, with a mean age of 61.2 years and median follow up of 15 months. 12.7% (9/71) of patients achieved a pCR, while the remaining 87.35% (62/71) were no-pCR. All pCR patients received and completed standard pre-operative chemotherapy-radiotherapy. 73.4% (52/71) of the patients had complications from chemoradiotherapy. Furthermore, there was a significant association between having a significant response to treatment and achieving a pCR; where 78% (7/9) of pCR patients had a significant response to treatment. Overall, 4/71 patients had a local recurrence, 22.2% (2/9) pCR and 3.2% (2/62) no-pCR. Those with no-pCR had a recurrence at 1 and 2.2 years post diagnosis, while those with pCR had a recurrence at 3.7 years. Conclusions: This study suggests that patients undergoing standard pre-operative chemoradiotherapy are likely to have a significant response and achieve a pCR. Based on this study, although a pCR does not prevent the risk of recurrence, it delays the onset of local recurrence. Longer follow-up is required to determine if these results are robust and to develop future studies to improve efficacy of treatment delivery in LARC patients.
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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 | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.001 | 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".