Complete pathological response of colorectal peritoneal metastases in Lynch syndrome after immunotherapy case report: is a paradigm shift in cytoreductive surgery needed?

BACKGROUND: We report the first case of a patient affected by peritoneal metastases from colon cancer, arising in the context of Lynch syndrome with pathological complete response. The patient was treated with immunotherapy and cytoreductive surgery. This paper discusses the implications of these novel therapies for the management of PM. CASE PRESENTATION: A 50-year-old man affected by Lynch syndrome was referred to our institution for metachronous peritoneal recurrence of ascending colon adenocarcinoma. As a second-line treatment, he received Nivolumab therapy with stable disease. Patient underwent cytoreductive surgery with residual disease and a pathological complete response. Flow cytometry described a particular immune sub-population response. There was no evidence of disease progression after nine months. CONCLUSION: This is the first report of a Lynch patient affected by peritoneal metastases of colorectal cancer, treated with cytoreductive surgery (CRS) and resulting in a pathological complete response after immune checkpoint inhibitors treatment (ICIs). This case report may suggest that patients with peculiar immunological features could benefit from a tailored approach, since "classical" CRS paradigms may not effectively predict the clinical outcome. Further large-scale studies are needed to determine the correct operative management of such patients (tailored or "standard" CRS), defining the correct surgical timing and eventual discontinuation of ICI therapy after surgery.

Different patterns of 11q allelic losses in digestive endocrine tumors.

Most foregut digestive endocrine neoplasms may be associated with the multiple endocrine type 1 (MEN-1) syndrome. In contrast, midgut/hindgut carcinoids never show such association. To investigate the pathogenetic involvement of the MEN-1 gene and of putative additional oncosuppressor gene(s) distal to it, a comparative analysis of loss of heterozygosity (LOH) at chromosome 11q13 to 11qter was performed in 27 foregut (pancreatic endocrine tumors [PETs]), 23 midgut (ileal and appendiceal), and 3 hindgut (rectal) endocrine tumors. LOH at the MEN-1 gene locus at 11q13 was observed in 52% of the 23 sporadic and in all 4 MEN-1-associated PETs and was found to consistently and continuously span to the most distal marker investigated at 11qter. In contrast, only occasional, discontinuous, and mostly interstitial LOH for 11q markers was observed in ileal (midgut) carcinoids, whereas no LOH was found in all appendiceal (midgut) and rectal (hindgut) carcinoids. The consistent extension of LOH from the MEN-1 region to 11qter in sporadic PETs suggests a mechanism of gene inactivation via chromosomal breakage and complete loss of chromosome 11q; furthermore, these results expand beyond the 11q13 region the search for additional oncosuppressor gene(s) potentially involved in the genesis of these neoplasms. The low frequency, limited extension, and discontinuous distribution of 11q deletions in midgut/hindgut carcinoids suggest that MEN-1 gene is not involved in the pathogenesis of these tumors.

Decreased total lymphocyte counts in pancreatic cancer: an index of adverse outcome.

OBJECTIVES: An impaired host immunity might concur in determining the dismal prognosis of patients with pancreatic cancer (PC). Our aim was to ascertain whether the immunophenotype pattern of blood lymphocytes in PC correlates with tumor stage, grade, or survival. METHODS: We studied 115 patients with PC, 44 with chronic pancreatitis (CP), 23 with tumors of the pancreatico-biliary tract, and 34 healthy controls (CS). Survival data were available for 77 patients with PC. Lymphocyte subsets were determined by fluorescent activated cell sorter (FACS) analysis. RESULTS: In patients with PC, total lymphocyte counts were lower than in CP or CS, and CD8 lymphocyte subset levels were higher with respect to CS. Lower circulating lymphocytes were found in advanced PC stages (IIB-IV; chi2 = 11.55, P < 0.05) compared with stages 0 to IIA. Cox regression analysis, made considering total lymphocyte counts and tumor stage as covariates, was found to be significant for both tumor stage (P < 0.001) and total lymphocyte counts (P < 0.05). CONCLUSIONS: The reduction of total lymphocytes in blood is the main immunologic change in advanced PC. The survival of these patients depends mainly on tumor stage, but it is also affected by the number of circulating lymphocytes, suggesting that the immune system plays an important role in pancreatic adenocarcinoma immunosurveillance and immunoediting.