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Peritoneal Cancer Index (PCI)

Quantification of Peritoneal Disease Extent
Scores peritoneal tumour burden across 13 abdomino-pelvic regions (0–3 each) to give a total PCI (0–39). Used intraoperatively and on CT/laparoscopy to guide candidacy for cytoreductive surgery (CRS) and HIPEC.
Surgical Oncology Peritoneal Disease CRS HIPEC
PCI Calculator

Score each of the 13 regions: 0=no tumour, 1=≤0.5 cm, 2=0.5–5 cm, 3=>5 cm or confluence

Lesion Size (LS) Scoring

LS ScoreTumour SizeDescription
LS 0No tumourNo peritoneal implants seen in the region
LS 1≤0.5 cmImplants up to 0.5 cm in greatest diameter
LS 20.5–5 cmImplants between 0.5 cm and 5 cm
LS 3>5 cm or confluenceImplants larger than 5 cm, or confluent disease covering the region

Each of the 13 abdomino-pelvic regions receives a lesion size (LS) score from 0 to 3. The total PCI is the sum of all 13 LS scores, ranging from 0 (no disease) to 39 (maximal peritoneal burden).

PCI Interpretation by Tumour Type

TumourPCI CutoffRecommendation
Colorectal peritoneal mets≤20Consider CRS+HIPEC (Verwaal RCT)
Appendix mucinous (DPAM)≤39CRS+HIPEC (high tolerance for disease burden)
Appendix mucinous (PMCA)≤20Consider if complete cytoreduction achievable
Gastric cancer≤6Very selected cases only; high recurrence risk
Ovarian cancer≤25CRS standard of care; optimal cytoreduction goal

Completeness of Cytoreduction (CC) Score

The CC score describes residual disease after cytoreductive surgery and is the most powerful predictor of survival in peritoneal surface malignancy:

CC ScoreResidual DiseaseClinical Significance
CC-0No visible residual tumourPotentially curative — survival benefit confirmed
CC-1Residual nodules ≤0.25 cmPotentially curative — HIPEC can penetrate residual disease
CC-2Residual nodules 0.25–2.5 cmPalliative intent only; no survival benefit over systemic therapy
CC-3Residual nodules >2.5 cmPalliative intent; significant morbidity without survival gain

CC-0 and CC-1 are the only acceptable completeness levels when performing CRS+HIPEC with curative intent. CC-2 and CC-3 resections expose patients to major surgical morbidity without survival benefit and should only be undertaken with careful multidisciplinary team discussion.

Clinical Application

  • PCI must always be interpreted alongside achievable completeness of cytoreduction — high PCI with achievable CC-0 may be preferable to low PCI with probable CC-2
  • Preoperative CT underestimates PCI by up to 30% — diagnostic laparoscopy is recommended for staging prior to definitive CRS+HIPEC
  • High PCI alone is not an absolute contraindication — histology (DPAM vs PMCA vs colorectal), patient fitness, and centre experience all modify the decision
  • The Peritoneal Surface Oncology Group International (PSOGI) recommends multidisciplinary evaluation at specialist centres before proceeding to CRS+HIPEC
  • Small bowel involvement (regions 9–12) is particularly prognostic — confluent disease here generally precludes complete cytoreduction
  • Neoadjuvant systemic chemotherapy (FOLFOX/FOLFIRI) may reduce PCI and improve cytoreduction completeness in colorectal peritoneal metastases

References

  1. Jacquet P, Sugarbaker PH. Clinical research methodologies in diagnosis and staging of patients with peritoneal carcinomatosis. Cancer Treat Res. 1996;82:359–374.
  2. Verwaal VJ, et al. Randomized trial of cytoreduction and hyperthermic intraperitoneal chemotherapy versus systemic chemotherapy and palliative surgery in patients with peritoneal carcinomatosis of colorectal cancer. J Clin Oncol. 2003;21(20):3737–3743.
  3. Glehen O, et al. Cytoreductive surgery combined with perioperative intraperitoneal chemotherapy for the management of peritoneal carcinomatosis from colorectal cancer. J Clin Oncol. 2004;22(16):3284–3292.

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