Pathologic T1 and T2 encapsulated invasive carcinomas arising from mucinous cystic neoplasms of the pancreas have favorable prognosis and might be treated conservatively

Abstract

Carcinoma arising from a mucinous cystic neoplasm (MCN) of the pancreas is termed MCN with associated invasive carcinoma (MCN‐AIC) in the fifth WHO classification of digestive tumors (2019). The prognosis of this malignancy varies depending on the relationship of the invasive carcinoma to the cyst capsule, but limited data are available. This study identified 165 surgically resected MCNs including 15 MCN‐AICs from a single center between 2008 and 2018 and analyzed their clinicopathologic features. The results confirmed that non‐invasive MCNs were completely cured by surgery. All MCN‐AICs showing an encapsulated invasion pattern (defined as invasive carcinoma limited to the ovarian‐type stroma, cystic septa, and capsule) had an excellent prognosis with a 5‐year survival rate of 100%, even when the size of the invasive component was up to stage T2. By contrast, MCN‐AICs with extracapsular involvement had unfavorable clinical outcomes. Our study demonstrates that the pattern of invasion of MCN‐AIC can predict patient prognosis. Pathologic stage T1 and T2 encapsulated MCN‐AICs may be completely cured with surgical resection alone or when combined with postoperative chemotherapy.

Invasive pancreatic cystic neoplasm with favorable prognosis: A large retrospective cohort study over two decades

“…The risk of death in patients with stage N2 iIPMN was reduced by chemotherapy, whereas clinical outcomes were not improved by chemotherapy in any N stage patients with iMCN. Therefore, we recommend chemotherapy for iIPMN patients with lymph node positivity, which is consistent with previously published studies [14][15][16][17]. However, controversy exists on whether adjuvant treatment should be performed in patients without lymph node involvement.…”

Update on mucinous cystic neoplasm of the pancreas: a narrative review

“…However, pathologic features that are helpful in further predicting the clinical outcomes of MCN-AIC have not been well studied. Capsule invasion may be associated with a poor survival, [11–13] but findings from our most recent study suggest that pattern of invasion may have further prediction value [14] . Molecular changes similar to those found in PDAC had been identified in MCN, including KRAS, CDKN2A/p16, TP53, SMAD4 mutations, as well as others such as RNF43 and PIK3CA mutations [15–17] .…”

“…Capsule invasion may be associated with a poor survival, [11][12][13] but findings from our most recent study suggest that pattern of invasion may have further prediction value. [14] Molecular changes similar to those found in PDAC had been identified in MCN, including KRAS, CDKN2A/p16, TP53, SMAD4 mutations, as well as others such as RNF43 and PIK3CA mutations. [15][16][17] But their potential value in prognosis is unknown.…”

“…Invasive carcinoma 2 0 Lewis et al [12] Minimally invasive carcinoma (confined to the ovarian-type stroma) [14] ). MCN-AIC = mucinous cystic neoplasm with associated invasive carcinoma.…”

“…Figure 4. Diagram showing the two invasion patterns in MCN-AICs (Reprinted from Liang et al[14] ). MCN-AIC = mucinous cystic neoplasm with associated invasive carcinoma.…”