PERITONEAL CANCER
INDEX (PCI) EXPLAINED
The PCI score — from 0 to 39 — is the single most important number in peritoneal oncology. It quantifies the extent of your peritoneal disease, determines whether complete cytoreduction is surgically achievable, and predicts the likely outcome of CRS-HIPEC.
analyticsAt a Glance
- check_circlePCI scores 13 abdominal-pelvic regions from 0–3 based on the largest deposit in each region — maximum score 39
- check_circlePCI ≤20 is the general threshold for curative-intent CRS-HIPEC eligibility — specific thresholds vary by tumour type
- check_circleCT and MRI underestimate true PCI by 30–40% — diagnostic laparoscopy provides the definitive score
- check_circlePCI must be interpreted in the context of histology, not used in isolation — a PCI of 25 in PMP carries a different prognosis than PCI of 25 in gastric cancer
What Is the PCI and Why Was It Developed?
The Peritoneal Cancer Index was developed by Paul Sugarbaker — the surgeon who pioneered CRS-HIPEC — as a reproducible, standardised method to quantify peritoneal tumour burden before surgery. Before PCI, peritoneal disease was described in vague terms ('diffuse,' 'extensive') that made comparing outcomes between patients and centres impossible. PCI introduced a precise numerical language that is now used globally.
“The PCI is not just a number — it is the basis of the conversation between you and your surgeon about whether complete cytoreduction is achievable, what the surgery will involve, and what survival benefit you can realistically expect.”
The 13 Abdominal-Pelvic Regions
The abdomen and pelvis are divided into 13 regions: nine abdominal regions in a 3×3 grid (central, right upper, epigastric, left upper, left flank, left lower, pelvic, right lower, right flank) and four small bowel regions (upper jejunum, lower jejunum, upper ileum, lower ileum). Each region receives a score of 0–3 based on the largest tumour nodule present in that region.
Lesion Size Score (LS): 0 to 3
LS-0: no tumour in the region. LS-1: tumour nodules up to 0.5 cm. LS-2: nodules 0.5 cm to 5 cm. LS-3: nodules >5 cm or confluent disease covering the entire peritoneal surface of the region. The 13 region scores are summed to give the total PCI — maximum 39.
PCI Thresholds by Tumour Type: What Your Score Means
The prognostic significance of a given PCI score differs by tumour histology — PCI thresholds for CRS-HIPEC eligibility are not universal.
| Tumour Type | PCI Threshold for Surgery | Rationale | Outcome Context |
|---|---|---|---|
| Colorectal cancer (CRC) | ≤20 (strict); ≤17 at some centres | Higher PCI associated with inability to achieve CC-0/1 resection | Median OS 30–40 months with CC-0; 5-year OS ~30% at most centres |
| Ovarian cancer | No strict upper limit — debulking goal drives decision | Complete or near-complete debulking is the primary aim regardless of PCI | Median OS improvement with HIPEC regardless of PCI in OVHIPEC trial |
| Pseudomyxoma peritonei (PMP) — low-grade | No absolute cutoff — PCI 30–39 may still be operable | PMP grows slowly — even extensive disease can be completely removed | 10-year OS >80% for complete resection regardless of initial PCI |
| Appendiceal cancer (DPAM/PMCA) | ≤20 for PMCA; more liberal for DPAM | Aggressive histology (PMCA) with high PCI carries very poor prognosis | DPAM: 10-year OS >70%; PMCA: 5-year OS ~30% even with surgery |
| Gastric cancer | ≤6–12 (strict patient selection) | Gastric PC with high PCI rarely achieves complete cytoreduction | Median OS 15–24 months for selected PCI <12 patients |
| Peritoneal mesothelioma | ≤30 at experienced centres | Epithelioid subtype can achieve long survival even with higher PCI | Median OS 40–92 months for epithelioid; 10–15 months for biphasic |
| Uterine cancer (selected) | ≤12–15 investigational threshold | Limited data; being evaluated in clinical trials | Insufficient evidence for routine recommendation; specialist discussion required |
How Your PCI Is Assessed: From Imaging to Laparoscopy
PCI assessment follows a sequential approach — from cross-sectional imaging to the definitive surgical assessment at laparoscopy or open surgery.
- 1
CT Scan PCI Estimation
Multiphase CT with IV and oral contrast is the standard first-line PCI estimation tool. An experienced radiologist or peritoneal oncology surgeon reviews the scan using the 13-region framework, assigning a score to each visible region of disease. CT underestimates true PCI by 30–40%, particularly for deposits on small-bowel surfaces and in the pelvis.
- 2
MRI Peritoneal Protocol (DWI)
Diffusion-weighted MRI is significantly more sensitive than CT for deposits ≤5 mm. It is increasingly used at specialist centres to identify small-volume disease that CT misses — particularly in the pelvis, on the liver capsule, and on the bowel surface. MRI provides a more accurate pre-operative PCI estimate than CT alone.
- 3
PET-CT
FDG-PET identifies extra-abdominal disease that would change management — mediastinal lymph nodes, bone metastases, or pleural disease. Less useful than CT/MRI for PCI scoring itself due to limited spatial resolution for small peritoneal deposits.
- 4
Diagnostic Laparoscopy
The definitive PCI assessment — performed at a specialist peritoneal oncology centre under general anaesthesia. All 13 regions are directly visualised, deposits are measured, small-bowel mesenteric involvement is assessed, and biopsies are taken. Laparoscopy identifies cases where CT-estimated PCI of 15 is actually 28 at direct visualisation — avoiding an unnecessary major operation.
- 5
Intraoperative PCI at CRS
The final, definitive PCI is recorded at the start of the CRS-HIPEC operation after laparotomy and full abdominal exploration. This intraoperative PCI is the most accurate of all — and forms the basis of outcome prediction in published series.
How PCI Predicts Survival After CRS-HIPEC for Colorectal Cancer
The following data illustrate the relationship between PCI and survival outcomes after CRS-HIPEC for colorectal peritoneal metastases — showing why PCI threshold selection is fundamental to patient selection.
Median Overall Survival by PCI Category — CRC Peritoneal Metastases
Pooled from PSOGI international registry and French multicentre series; CC-0/1 resection cases only
- PCI 1–648+ months
- PCI 7–1238 months
- PCI 13–2028 months
- PCI 21–3016 months
- PCI >309 months
CT-Estimated PCI vs Laparoscopic PCI: The Accuracy Gap
One of the most clinically important facts about PCI assessment is that CT significantly underestimates true disease extent — affecting eligibility decisions made on imaging alone.
CT-Estimated PCI (Pre-Op)
- Underestimates by 30–40% on averageCT misses deposits ≤5 mm on bowel and mesenteric surfaces — which are invisible on cross-sectional imaging but visible and measurable at direct laparoscopic inspection.
- Small-bowel surface is a CT blind spotThe most critical information for CRS-HIPEC eligibility — the extent of small-bowel mesenteric involvement — is poorly assessable on CT and may only be fully revealed at laparoscopy.
- May lead to over- or under-triageA CT-estimated PCI of 12 might be a surgical PCI of 20 at laparoscopy — the difference between curative and palliative intent. Conversely, a CT PCI of 22 might be 17 at laparoscopy.
- Appropriate for initial screeningCT is the right first step — rapid, widely available, and sufficient to identify patients with obviously high PCI (>30) who do not need diagnostic laparoscopy.
Laparoscopic / Surgical PCI (Definitive)
- The only reliable assessment of small-bowel rootLaparoscopy directly visualises the small-bowel mesentery — the critical anatomical region where involvement determines whether complete cytoreduction is technically possible.
- Changes management in 30–40% of patientsPublished series show that diagnostic laparoscopy changes the treatment plan — either upgrading to surgery or downgrading to palliative care — in approximately one-third of patients compared to CT-alone staging.
- Required before CRS-HIPEC at specialist centresAll high-volume peritoneal oncology centres perform diagnostic laparoscopy before committing to CRS-HIPEC — it is a standard pre-operative step, not an optional extra.
- Brief procedure with rapid recoveryDiagnostic laparoscopy takes 30–60 minutes under general anaesthesia; most patients are discharged within 24 hours. The small risk and recovery time are justified by the major management information it provides.
More from the Peritoneal Oncology Resource Library
Continue exploring CRS-HIPEC — from what peritoneal carcinomatosis is to surgery details and specific tumour types.
Frequently Asked Questions
Common questions from patients about the PCI score and what it means for their treatment options.
About the PCI Score
My CT report does not mention a PCI score — does that mean I do not have peritoneal carcinomatosis?
No. The PCI score is a surgical staging tool, not a standard radiology reporting term — most routine CT reports describe peritoneal findings descriptively ('peritoneal thickening,' 'omental caking,' 'peritoneal nodules') without assigning a formal PCI. The absence of a PCI number in your report does not mean you have been assessed for it. A peritoneal oncology surgeon or CancerFax specialist can review your existing imaging and provide a preliminary PCI estimate using the standardised 13-region scoring framework.
My surgeon said my PCI is too high for surgery. Is there a second opinion I can seek?
Yes — and seeking a second opinion is strongly recommended for peritoneal carcinomatosis. PCI assessment from imaging requires specific expertise in peritoneal surface oncology that is not universally available. A CT-estimated PCI of 25 may represent a surgical PCI of 18 at diagnostic laparoscopy at a specialist centre — a difference that takes a case from 'inoperable' to 'potentially curable.' CancerFax can arrange a second opinion with a high-volume CRS-HIPEC surgeon who will review your imaging specifically for surgical PCI and eligibility.
Does a low PCI guarantee that CRS-HIPEC will cure my cancer?
A low PCI is necessary but not sufficient for curative intent. The other critical factor is the completeness of cytoreduction achieved at surgery — called the CC score (CC-0: no residual disease, CC-1: residual nodules ≤2.5 mm, CC-2: residual nodules 2.5 mm–2.5 cm). Survival benefit from CRS-HIPEC is primarily driven by achieving CC-0 or CC-1 resection. A PCI of 8 with CC-2 residual disease has a worse prognosis than a PCI of 15 with CC-0 resection. Both PCI and the expected completeness of resection must be discussed together with your peritoneal oncology surgeon.
How CancerFax Helps
CancerFax is a specialist cancer access and patient-navigation platform. We help patients and families understand their options, organise medical records, coordinate hospital communication, and support cross-border treatment planning where appropriate.
We help collect and organise reports, scans, pathology, biomarker results, and treatment history for structured case review.
We communicate with hospitals or trial teams to assess whether a case may be suitable for further screening.
We support appointment coordination, document submission, translation, and direct communication with international departments.
For international patients, we help with practical coordination — travel planning, hospital admission guidance, and local support.
If this option is not suitable, we help explore other relevant treatments, clinical trials, or advanced care pathways.
From inquiry through to follow-up, our coordinators provide a single point of contact for the family.
CancerFax does not guarantee treatment access, eligibility, or clinical outcome. Our role is to help patients access accurate information, structured review, and appropriate specialist pathways.
Want a Specialist PCI Assessment?
CancerFax can arrange a specialist peritoneal oncology review of your imaging to provide a PCI estimate — and connect you with CRS-HIPEC surgeons who can perform definitive diagnostic laparoscopy and staging at centres in China and India.
This content is for informational purposes only and does not constitute medical advice. Always consult a qualified oncologist before making treatment decisions.