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With the prevalence of endoscopic submucosal dissection and endoscopic full thickness resection, which enable complete resection of T1 colorectal cancer with a negative margin, the treatment strategy following endoscopic resection has become more important. The necessity of secondary surgical resection is determined on the basis of the risk of lymph node metastasis according to the histopathological findings of resected specimens because ~10% of T1 colorectal cancer cases have lymph node metastasis. The current Japanese treatment guidelines state four risk factors for lymph node metastasis: lymphovascular invasion, histological differentiation, depth of submucosal invasion, and tumor budding. These guidelines have succeeded in stratifying the low‐risk group for lymph node metastasis, in which endoscopic resection alone is acceptable for cure. On the other hand, there are some problems: there is variation in diagnosis methods and low interobserver agreement for each pathological factor and 90% of surgical resections are unnecessary, with lymph node metastasis negativity. To ensure patients with T1 colorectal cancer receive more appropriate treatment, these problems should be addressed. In this systematic review, we gave some suggestions to these practical issues of four pathological factors as predictors.

Background: Human obstructive airway diseases are histopathologically characterized by inflammatory cell infiltration, goblet cell hyperplasia, and mucus hypersecretion in airways. We prepared a rat model of airway injury by exposure of sulfur dioxide (SO₂) and then evaluated the effects of S-carboxymethylcysteine (S-CMC), a mucoregulant. Methods: Rats were exposed to SO₂ gas for 44 days and orally given S-CMC at 250 mg/kg, twice daily, from 21 to 44 days of exposure for histopathological and immunohistochemical evaluation. Results: SO₂ exposure induced inflammatory cell infiltration and mucus cell increase in rat airways. S-CMC treatment significantly decreased this inflammatory cell infiltration in proximal and peripheral airways. Morphometrically, SO₂ exposure significantly increased the number of Alcian blue (pH 2.5)- and periodic acid-Schiff (AB/PAS)-positive cells in rat airways (11.8 × 10^–2 cell/nuclear profiles per micrometer basement membrane) compared to normal rat airways (1.6 × 10^–2 cell/nuclear profiles per micrometer basement membrane). S-CMC treatment significantly decreased the number of AB/PAS-positive cells (4.4 × 10^–2 cell/nuclear profiles per micrometer basement membrane, p < 0.01 vs. SO₂-exposed rats). Immunohistochemically, SO₂ exposure increased the expression of mucin 5AC (MUC5AC) protein in the airway epithelium of rats, but S-CMC treatment inhibited the increase. Conclusions: The increased mucus cells and MUC5AC protein expression seem associated with SO₂-induced airway inflammation in rats. The fact that S-CMC suppresses airway inflammation and the increase in mucus cells and MUC5AC protein expression suggests that this mucoregulant may be advantageous in the treatment of inflammatory airway diseases with goblet cell hyperplasia.

Objectives Complete endoscopic healing, defined as Mayo endoscopic score (MES) = 0, is an optimal target in the treatment of ulcerative colitis (UC). However, some patients with MES = 0 show clinical relapse within 12 months. Histologic goblet mucin depletion has emerged as a predictor of clinical relapse in patients with MES = 0. We observed goblet depletion in vivo using an endocytoscope, and analyzed the association between goblet appearance and future prognosis in UC patients. Methods In this retrospective cohort study, all enrolled UC patients had MES = 0 and confirmed clinical remission between October 2016 and March 2020. We classified the patients into two groups according to the goblet appearance status: preserved‐goblet and depleted‐goblet groups. We followed the patients until March 2021 and evaluated the difference in cumulative clinical relapse rates between the two groups. Results We identified 125 patients with MES = 0 as the study subjects. Five patients were subsequently excluded. Thus, we analyzed the data for 120 patients, of whom 39 were classified as the preserved‐goblet group and 81 as the depleted‐goblet group. The patients were followed‐up for a median of 549 days. During follow‐up, the depleted‐goblet group had a significantly higher cumulative clinical relapse rate than the preserved‐goblet group (19% [15/81] vs. 5% [2/39], respectively; P = 0.02). Conclusions Observing goblet appearance in vivo allowed us to better predict the future prognosis of UC patients with MES = 0. This approach may assist clinicians with onsite decision‐making regarding treatment interventions without a biopsy.