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Cellularity of mucus is a prognostic variable in low-grade appendiceal mucinous neoplasms
Paul H Sugarbaker1, John J Liang2, Tom Deng2
1Program in Peritoneal Surface Malignancy, Washington Cancer Institute, Washington, DC, USA.
Abstract:
For peritoneal metastases from a primary appendiceal mucinous neoplasm to exist, the thin wall of the appendix must perforate to allow mucus or mucus plus tumor cells to gain access to the peritoneal spaces. The proportion of specimens containing tumor cells within mucus as compared to mucus only outside the appendix may have prognostic significance. The histopathology of tumor masses was determined from the specimens resected at the cytoreductive surgery (CRS). The presence versus absence of tumor cells in mucus and the proportion of specimens with tumor cells was determined and correlated with the overall survival of these patients. In 418 patients with a complete cytoreduction for a low-grade appendiceal mucinous neoplasm (LAMN), the cellularity of all resected specimens was determined. The hazard ratio of overall survival of patients whose specimens had no cells as compared to specimens with cells in mucus by histology was 4.41 (1.61, 12.1) (p = 0.0039). If overall survival of patients with all specimens without tumor cells was compared to patients with specimens with 1-99 % tumor and compared to patients with 100 % of specimens with tumor cells, the hazard ratios were 4.3 (1.34, 13.8) (p = 0.0143) and 9.62 (2.93, 31.6) (p = 0.0002), respectively. The cellularity of mucus within the specimens removed by a complete CRS has strong prognostic implications in LAMN patients. LAMN with acellular specimens (LAMNa) as compared to LAMN with tumor cells in specimens (LAMNb) should be staged as different histologic subtypes of mucinous appendiceal neoplasms.
Insights
The presence of tumor cells in mucus from appendiceal mucinous neoplasms significantly impacts patient survival. Acellular specimens indicate a better prognosis than those with tumor cells, suggesting distinct histologic subtypes.
Area of Science:
- Oncology
- Gastroenterology
- Surgical Pathology
Background:
- Peritoneal metastases from appendiceal mucinous neoplasms arise from appendix perforation.
- The proportion of tumor cells versus mucus alone in peritoneal specimens may influence prognosis.
Purpose of the Study:
- To determine the prognostic significance of tumor cells within mucus in patients with low-grade appendiceal mucinous neoplasm (LAMN).
- To correlate the cellularity of resected specimens with overall survival after cytoreductive surgery (CRS).
Main Methods:
- Histopathological analysis of resected specimens from 418 patients undergoing complete CRS for LAMN.
- Determination of the presence and proportion of tumor cells in mucus within specimens.
- Correlation of specimen cellularity with overall survival rates.
Main Results:
- Patients with acellular mucus specimens had a significantly better overall survival compared to those with tumor cells present (Hazard Ratio = 4.41).
- Increasing proportions of tumor cells in specimens correlated with worse survival outcomes (HRs of 4.3 and 9.62 for 1-99% and 100% tumor cells, respectively).
Conclusions:
- Mucus cellularity in specimens from complete CRS is a strong prognostic indicator in LAMN.
- LAMN with acellular specimens (LAMNa) and LAMN with tumor cells (LAMNb) should be classified as distinct histologic subtypes.
