A retrospective outcome study in the elder patient with locally advanced rectal cancer treated with hypofractionated or conventional preoperative radiotherapy
Bibliographic record
Abstract
Background: Neoadjuvant chemoradiotherapy is considered the standard approach for T3-4 M0 rectal cancer; however, the optimal dose remains undefined for the elderly. We performed a retrospective analysis to compare conventional (C) and hypofractionated (HF) schedules in elderly patients. We compared survival rates, local control and morbidity. Methods: From 2000 to 2008, 177 patients older than 65 years with T3-4 M0 rectal cancer received preoperative radiotherapy according to either a conventional protocol (45 to 50.4 Gy in 1.8-2 Gy daily fractions) or a hypofractionated (39 Gy in 3 Gy daily fractions) protocol. Fifty-five patients in the conventional group and none of the patients in the hypofractionated group received concomitant chemotherapy. Both groups were equivalent in terms of their characteristics. The median follow-up was 36 months. Results: The occurrence of early grade 3-4 radiation toxicity was equivalent between the 2 groups (7%). Surgery was performed in 98% of the patients in the HF group versus 92% in the conventional ( p =0.08). The delay between radiotherapy and surgery was 22 days in the HF group versus 45 days in the conventional group ( p =0.0021). The downstaging rates were 39% in HF group and 45% in the C group ( p =0.53). For lower rectum tumors, the conservative surgery rates were 43% in the HF group and 35% in the C group, ( p =0.52). The postoperative death rates at 30 days were equal between the two groups (3%). The 5-year local control rates was 87.3% in group C and 91.7% in group HF ( p =0.5). Based on a Kaplan-Meier analysis, the 1-, 3- and 5-year overall survival rates were 88%, 67% and 45%, respectively, in the C group and 84%, 60% and 39%, respectively, in the HF group ( p =0.28). In a multivariate analysis, the prognostic factors for overall survival were a Charlson index < 2 ( p =0.0034 HR=0.3), pT stage ≤2 ( p =0.0042 HR=0.16), pN0 stage ( p =0.0072 HR=0.388), and downstaging ( p =0.0498 HR=0.651). Radiation schedule and concomitant chemotherapy had no impact. Conclusion: In this series, the local control rates and the overall survival results are equivalent for patients treated with HP and C radiation schedules. As hypofractionated radiotherapy is more convenient for elderly patients and has equivalent morbidity, additional prospective studies with this population could be of great interest.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| 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) | 0.001 | 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 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".