The KTP Laser Is an Effective Treatment for Chronic Radiation Proctopathy
Bibliographic record
Abstract
Purpose: Chronic radiation proctopathy (CRP) is a complication of radiotherapy to the pelvis. The KTP (potassium titanyl phosphate) laser is a Nd/YAG-driven unit that uses light with a wavelength of 532nm. The purpose of this study was to study the therapeutic results of the KTP laser. We also evaluated whether the presence of certain co-morbidities that would predispose patients undergoing external beam radiotherapy (EBRT) to develop chronic bleeding from endoscopically proven CRP. Methods: All the patients treated with the KTP laser for chronic bleeding secondary to CRP at the BCCA were assessed from 1997 to 2002. Bleeding magnitude and frequency were graded on a 5-point scale with a mean follow-up of 17 months. The presence of hypertension, diabetes and a >20 pack year smoking history were recorded on all patients with prostate cancer over the same time period treated with EBRT with endoscopically proven CRP. We then used a 3:1 age matched cohort as a control group and performed a statistical analysis. Results: 52 patients with a mean age of 69 years (41 to 82 years) were treated. 38 were men treated for prostate cancer, 14 were women treated for gynecological malignancies. The mean EBRT dose was 5839 cGy (4839–7200cGy) in 50 patients. 12 also received intracavitary insertion with an average of 2107cGy (530–2700cGy). 2 patients received I125 brachytherapy to the prostate. An average of 2.4 KTP laser treatments were performed with an average follow up of 17.1 months (1 to 65 months). 32 (61.5%) patients had resolution of bleeding, 14 (26.9%) had significant reduction in bleeding, 5 (9.6%) failed treatment and 1 (2%) underwent hemicolectomy secondary to a rectal ulcer. Mean time to symptoms was 9.6 months (0–43 months) post radiotherapy. Treatments were well tolerated. 36 patients were analyzed and compared to 108 age matched control. The odds ratio for developing chronic bleeding from CRP was 1.18 for hypertension (p = 0.5), 1.20 for a >20 pack year smoking history (p = 0.24) and 1.20 for diabetes mellitus (p = 0.91). Conclusions: The KTP laser is a safe and effective treatment for rectal bleeding from CRP. 88.4% of patients either had complete resolution or a significant decrease in bleeding. There was an increased odds ratio for developing CRP after EBRT with the presence of these factors but it did not reach statistical significance. This is the largest study to evaluate the KTP laser in the management of CRP.
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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 | 0.000 |
| 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) | 0.003 | 0.001 |
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".