Reappraisal of T1b gallbladder cancer (GBC): clinicopathologic analysis of 473 in situ and invasive GBCs and critical review of the literature highlights its rarity, and that it has a very good prognosis

There are highly conflicting data on relative frequency (2-32%), prognosis, and management of pT1b-gallbladder carcinoma (GBC), with 5-year survival ranging from > 90% in East/Chile where cholecystectomy is regarded as curative, versus < 50% in the West, with radical operations post-cholecystectomy being recommended by guidelines. A total of 473 in situ and invasive extensively sampled GBCs from the USA (n = 225) and Chile (n = 248) were re-evaluated histopathologically per Western invasiveness criteria. 349 had invasive carcinoma, and only 24 were pT1. Seven cases previously staged as pT1b were re-classified as pT2. There were 19 cases (5% of all invasive GBCs) qualified as pT1b and most pT1b carcinomas were minute (< 1mm). One patient with extensive pTis at margins (but pT1b focus away from the margins) died of GBC at 27 months, two died of other causes, and the remainder were alive without disease (median follow-up 69.9 months; 5-year disease-specific survival, 92%). In conclusion, careful pathologic analysis of well-sampled cases reveals that only 5% of invasive GBCs are pT1b, with a 5-year disease-specific survival of > 90%, similar to findings in the East. This supports the inclusion of pT1b in the "early GBC" category, as is typically done in high-incidence regions. Pathologic mis-staging of pT2 as pT1 is not uncommon. Cases should not be classified as pT1b unless extensive, preferably total, sampling of the gallbladder to rule out a subtle pT2 is performed. Critical appraisal of the literature reveals that the Western guidelines are based on either SEER or mis-interpretation of stage IB cases as "pT1b." Although the prognosis of pT1b-GBC is very good, additional surgery (radical cholecystectomy) may be indicated, and long-term surveillance of the biliary tract is warranted.

Risk stratification for lymph node metastasis using Epstein-Barr virus status in submucosal invasive (pT1) gastric cancer without lymphovascular invasion: a multicenter observational study

BACKGROUND

Lymphovascular invasion (LVI) is a strong predictive factor for lymph node metastasis (LNM) in early gastric cancer (GC). This study investigated the risk for LNM in pT1b GC without LVI based on Epstein-Barr virus (EBV) status in addition to conventional clinicopathological parameters.

METHODS

In total, 847 consecutive patients of pT1b GC without LVI who underwent surgery at three high-volume centers between 2005 and 2014 were retrospectively analyzed. Clinicopathological parameters and EBV status were evaluated, and univariate and multivariate analyses were performed to estimate LNM risk. With regard to the presence of those three parameters, risk stratification for LNM was performed and compared with a previously proposed risk classification that included low-risk (LNM < 3.0%), intermediate-risk (LNM ≥ 3.0 and < 19.6%), and high-risk (LNM ≥ 19.6%) groups.

RESULTS

EBV-positive GC (EBVGC) accounted for 11.3% (96 of 847) of cases; LNM was lower in EBVGC than in non-EBVGC (1 of 96, 1.0% vs. 71/751, 9.5%). In the multivariate analysis, non-EBVGC [odds ratio (OR) 10.8, 95% confidence interval (CI) 1.48-78.9], age < 65 years (OR 2.13, 95% CI 1.30-3.48), and tumor diameter > 3 cm (OR 2.26, 95% CI 1.36-3.74) were independent risk factors for LNM. Patients with EBVGC were at low risk for LNM whereas those with all of three independent risk factors were at high risk (36 of 168, 21.4%, 95% CI 15.5-28.4).

CONCLUSION

LNM risk stratification that includes EBV status is useful for clinical decision-making in pT1b GC cases without LVI.

Epstein-Barr virus status is a promising biomarker for endoscopic resection in early gastric cancer: proposal of a novel therapeutic strategy

BACKGROUND

Epstein-Barr virus-positive gastric cancer (EBVGC) is associated with a low prevalence of lymph node metastasis (LNM); however, EBV status is not considered in the indication of endoscopic resection (ER). We aimed to clarify the implication of EBV status for ER of pT1b GC.

METHODS

Consecutive cases of pT1b GCs treated with surgery between 2005 and 2014 were retrospectively analyzed. Clinicopathological factors and LNM status were compared between EBVGC and non-EBVGC groups.

RESULTS

EBVGC accounted for 7.9% (71 of 898) cases. Compared to non-EBVGC, EBVGC was more frequent in males (p = 0.0055), the upper third region (p < 0.0001), showed elevated growth features (p = 0.0059), and was associated with a lower frequency of accompanying ulceration (p = 0.002), greater depth of submucosal invasion (p = 0.017), and lower frequency of lymphatic invasion (p < 0.0001). Frequency of LNM was significantly lower in EBVGC than in non-EBVGC (4.2% vs. 21.9%, p < 0.0001). In EBVGC, tumors without lymphovascular invasion showed significantly lower frequency of LNM than those with lymphovascular invasion (0 of 50, 0%; vs 3 of 21, 14.3%; p = 0.023). Histologically, 84.5% (60 of 71) of EBVGC included carcinomas with lymphoid stroma and/or lace pattern components.

CONCLUSIONS

pT1b EBVGC is a convincing candidate for ER, regardless of risk factors other than lymphovascular invasion.

Implementation of the 7th edition AJCC staging system: Effects on staging and survival for pT1 melanoma. A Dutch population based study

In the 7^th edition of the AJCC staging system, the mitotic rate criterion replaced Clark level to increase correct classification of high-risk thin melanoma patients (pT1B). Additionally, sentinel node biopsy (SNB) was recommended for nodal staging of pT1B melanomas. The aim of this article was to evaluate the effects on pT1 substaging and clinical implications in the national pT1 melanoma population. All pT1 melanomas diagnosed in the Netherlands between 2003 and 2014 were selected from the Netherlands Cancer Registry (IKNL). Patients were stratified by cohort according to AJCC edition: (1) 2003-2009 (6^th ) and (2) 2010-2014 (7^th ). Relative survival was calculated to estimate melanoma-specific survival. A total of 29.546 pT1 melanoma patients were included. The pT1b proportion increased from 10.1% in Cohort 1 to 21.5% in Cohort 2. The proportion of performed SNBs per cohort increased: for pT1b melanomas alone from 4.5% to 13.0%. SNB positivity rate decreased from 10.5% to 8.8% for the entire pT1 population, and for pT1b melanomas from 11.3% to 8.6%. At 5 years, the relative survival rate was similar for pT1a and pT1b in both cohorts, namely, pT1a 100% vs pT1b 97% (Cohort 1), and pT1a 100% vs pT1b 98% (Cohort 2). The 7^th edition of the AJCC staging system has caused an increased number of patients to undergo SNB, without an increase in SNB positivity rate. Survival between pT1 subgroups remains similar. The mitotic rate criterion for pT1b classification and the recommendation to perform SNB for pT1b melanomas should be reconsidered.