Clinical calculator summary
Original colorectal PSDSS
Clinical calculator summary
Original colorectal PSDSS
A 2-22 additive score using symptoms, PCI category, and joint histopathology.
Evidence-based context for fast calculator use
- Purpose:
- Reproduce the source-defined PSDSS stage for colorectal peritoneal metastases.
- Population:
- Patients with colorectal cancer and peritoneal metastases in the original historical cohorts.
- Factors:
- Clinical symptoms, PCI category, Joint histopathology and nodal category
- Reference:
- Pelz JO, et al. J Surg Oncol. 2009;99(1):9-15. PMID 18937291.
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Peritoneal Surface Disease Severity Score (PSDSS)
Clinical Context & Background
This calculator implements the original Pelz 2009 Peritoneal Surface Disease Severity Score for colorectal cancer with peritoneal metastases. The score has three components: clinical symptoms, Peritoneal Cancer Index category, and a joint primary-tumor histopathology category that already incorporates nodal status.
The PCI middle category includes both 10 and 20. The histopathology categories must be selected exactly as published; nodal status is not scored separately. The result is an exact integer from 2 to 22 and maps to PSDSS Stages I-IV without rounding.
The model is not applicable to colorectal cancer without peritoneal metastases or to appendiceal, ovarian, gastric, mesothelioma, or other peritoneal malignancies. It is historical prognostic stratification, not an individualized survival estimate, resectability test, or CRS/HIPEC recommendation.
Formula Logic
Original colorectal PSDSS = clinical-symptom points (0, 1, or 6) + PCI-category points (1, 3, or 7) + joint histopathology points (1, 3, or 9); total 2-22.Reference Data
| PSDSS stage | Exact total | Interpretation |
|---|---|---|
| Stage I | 2-3 | Historical prognostic stratum |
| Stage II | 4-7 | Historical prognostic stratum |
| Stage III | 8-10 | Historical prognostic stratum |
| Stage IV | 11-22 | Historical prognostic stratum |
Clinical Workflow
Use, Interpret, And Continue The Patient Pathway
Expand for workflow guidance, limitations, examples, and related next steps.
Clinical Workflow
Use, Interpret, And Continue The Patient Pathway
Expand for workflow guidance, limitations, examples, and related next steps.
When To Use
- For source-faithful historical stratification of colorectal cancer with confirmed peritoneal metastases.
- Use the clinical-symptom, PCI, and joint histopathology categories from the original model.
How To Interpret
- Totals 2-3, 4-7, 8-10, and 11-22 map to PSDSS Stages I, II, III, and IV.
- The stage is a historical cohort stratum, not an individualized survival prediction.
What To Do Next
- Document the exact source categories used.
- Integrate the result with multidisciplinary imaging, disease biology, resectability, comorbidity, goals, and treatment-preference assessment.
Limitations
- Derived and supported in historical colorectal peritoneal-metastasis cohorts with treatment-era and referral-selection limitations.
- The 2010 cohort excluded non-colorectal origin, death within 30 days after exploration, and more than three extra-abdominal metastases.
- Not validated for other peritoneal malignancies or colorectal cancer without peritoneal metastases.
- Does not independently determine resectability or recommend CRS/HIPEC.
Calculation verification history
Verified
Calculation verification history
Verified: Production browser revalidation
- Three source-backed cases passed through visible production controls at PSDSS totals 2, 4, and 22.
- Stages I, II, and IV rendered as expected across low and maximum component profiles.
- No unexpected N/A, literal undefined value, stale control, unsupported gauge, or browser-console error was observed.
Case-level evidence is retained in validation/browser-revalidation/prostate-cancer-specific-disease-free-survival-psdss-2026-08-03.json.
: Production browser validation
- Ten source-backed cases were exercised on the public production route through visible browser controls; 10/10 case records passed their expected-versus-observed assertions across 11 visible submissions.
- Overall browser status: failed-console. medium: Production emitted minified React error #418 during route loads/reloads used by this run.
- Case-level inputs, expected and observed results, reset/repeat behavior, failure reproductions, and console evidence are retained in the production-browser evidence record.
Case-level production evidence is retained in validation/browser-production/prostate-cancer-specific-disease-free-survival-psdss.json.
: Full validation test
- 326/326 independent source-table, stage-boundary, malformed-input, UI, trace, presentation, reset, immutability, registry, report, history, and isolation checks passed.
- This verifies source-to-code implementation only; it is not independent clinical validation, an individualized survival estimate, resectability assessment, or treatment recommendation.
: Calculation, input-contract, and model-identity correction
- Corrected the public name to the original colorectal Peritoneal Surface Disease Severity Score while preserving the permanent bookmarked route.
- Restored the original three components and removed independent nodal points, favorable defaults, coercion, extra-field summation, and impossible totals.
- Corrected moderate N-positive, poorly differentiated, and signet-ring histopathology weights; removed the mixed survival table, candidacy labels, and prescriptive treatment claims.
Included in the current validation report.
Verification confirms the calculator implementation against the cited model; it is not independent clinical validation, regulatory approval, or medical advice.
Related Tools
Frequently Asked Questions
Is nodal status scored separately?
No. Nodal status is part of the published joint histopathology category and must not be added again.
Where do PCI values of exactly 10 and 20 belong?
Both are included in the 10-20 category, which contributes three points.
Does PSDSS determine CRS/HIPEC candidacy?
No. It is historical prognostic stratification and must not replace multidisciplinary resectability and treatment assessment.
Evidence-based oncology decision support. Verify with clinical guidelines.