Indications for additional volume studies for gland volume estimation in prostate cancer brachytherapy
Bibliographic record
Abstract
An estimated gland volume of > 60 cc is a relative contraindication to brachytherapy for prostate cancer. As volume estimation using biopsy ultrasound (Bx-US) alone may be inaccurate, many centers perform additional volume assessments prior to the brachytherapy procedure. At the study institution, computed tomography (CT) based volume assessments were routinely performed on all patients to determine brachytherapy eligibility. This study aimed to determine whether this CT imaging could be omitted for certain Bx-US based gland volume estimates. To investigate this, 1576 consecutive patients that received ultrasound based intraoperatively planned brachytherapy at a single comprehensive cancer center between 2003 and 2021 were reviewed. Gland volume as estimated by Bx-US, CT and magnetic resonance (MR) imaging were compared to intraoperatively contoured gland volume (ICGV) or the larger contoured gland volume on CT for any patients receiving neo-adjuvant androgen deprivation therapy (ADT) for gland downsizing (IM-US-corr). There was a significant difference between IM-US-corr and estimated gland volume for Bx-US (P < 0.001) and MR (P < 0.001), but not CT (P = 0.160). Bx-US and MR tended to underrepresent the IM-US-corr, with a > 20% difference from actual volume in 31% and 59% of cases, respectively. When Bx-US volume was estimated to be < 40 cc, < 50 cc and < 60 cc, an IM-US-corr > 60 cc was encountered in 2%, 5% and 7% of cases, respectively. In contrast, IM-US-corr > 60 cc was encountered in 0.2%, 1% and 2% of cases for CT estimates of < 40 cc, < 50 cc and < 60 cc. In patients with an estimated gland volume of < 50 cc by Bx-US, dedicated pre-operative volume studies are unlikely to alter management. However, patients above this cut-off stand to benefit from the use of additional volume assessment to better delineate gland volume and determine eligibility for brachytherapy.
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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 | 0.005 | 0.013 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| 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".