The Survival Benefit From the Addition of Radiation to Chemotherapy in Gastric Cancer Patients Following Surgical Resection

The Role of Surgery in the Management of Gastric Cancer: State of the Art

Surgery still represents the mainstay of treatment of all stages of gastric cancer (GC). Surgical resections represent potentially curative options in the case of early GC with a low risk of node metastasis. Sentinel lymph node biopsy and indocyanine green fluorescence are novel techniques which may improve the employment of stomach-sparing procedures, ameliorating quality of life without compromising oncological radicality. Nonetheless, the diffusion of these techniques is limited in Western countries. Conversely, radical gastrectomy with extensive lymphadenectomy and multimodal treatment represents a valid option in the case of advanced GC. Differences between Eastern and Western recommendations still exist, and the optimal multimodal strategy is still a matter of investigation. Recent chemotherapy protocols have made surgery available for patients with oligometastatic disease. In this context, intraperitoneal administration of chemotherapy via HIPEC or PIPAC has emerged as an alternative weapon for patients with peritoneal carcinomatosis. In conclusion, the surgical management of GC is still evolving together with the multimodal strategy. It is mandatory for surgeons to be conscious of the current evolution of the surgical management of GC in the era of multidisciplinary and tailored medicine.

Surgical Management of Gastric Cancer: A Review

Importance

Surgery plays a critical role in the management of all stages of gastric cancer.

Observations

For patients with early gastric cancer and low risk of lymph node metastasis, endoscopic therapy or surgery alone is potentially curative. Novel techniques, such as sentinel lymph node biopsy, may allow for greater use of stomach-sparing procedures that could improve quality of life without compromising oncologic outcomes; however, experience with these techniques is rare outside of East Asia, and studies of long-term outcomes are still ongoing. Patients with later-stage localized gastric cancer benefit from more extensive lymphadenectomy and multimodality therapy, as they are at risk for nodal and distant metastases. There have been recent advances in chemotherapy that have led to improved survival, but the optimal sequencing of multimodality therapy is still being investigated. Better systemic therapy may also increase the role of surgery for patients with oligometastatic disease. There are ongoing studies examining the efficacy of peritoneal-directed therapies in both patients with low-volume peritoneal disease and patients at high risk of peritoneal recurrence.

Conclusions and Relevance

The management of gastric cancer continues to evolve. Surgeons should be aware of novel surgical approaches currently under investigation as well as how surgery fits into the contemporary multidisciplinary approach to this disease.

A Comparison of Clinicopathologic Outcomes Across Neoadjuvant and Adjuvant Treatment Modalities in Resectable Gastric Cancer

IMPORTANCE

Treatment of resectable gastric cancer (RGC) uses a multimodal approach, including surgical treatment and chemotherapy with or without radiation therapy, and the optimal treatment strategy and timing of each of these modalities is unknown.

OBJECTIVE

To investigate the association of various neoadjuvant and adjuvant treatment modalities with pathologic complete response (pCR), surgical margin status (SMS), and overall survival (OS) in RGC.

DESIGN, SETTING, AND PARTICIPANTS

For this comparative effectiveness study, the National Cancer Database was interrogated to identify patients with RGC diagnosed from 2004 to 2015. Patients with gastric adenocarcinoma that was cT2-T4b, any N, and M0 and who underwent definitive surgical treatment were included.

MAIN OUTCOMES AND MEASURES

The association of 9 treatment groups (ie, neoadjuvant chemoradiation only [nCRT], neoadjuvant chemotherapy only, adjuvant chemotherapy only [aCT], adjuvant chemoradiation only [aCRT], neoadjuvant chemotherapy and adjuvant radiation, chemotherapy with timing unknown [CTTU], chemoradiation therapy with timing unknown, radiation therapy with timing unknown (RTTU), and no perioperative therapy [NT]) with 3 end points (ie, pCR, SMS, and OS) was analyzed. The analysis was done using logistic regression and Cox proportional hazards models with adjustment for baseline characteristics. Data were analyzed from September 2019 through February 2020.

RESULTS

Among 183 204 patients with RGC who were screened, 3064 patients were included in the analysis (median [IQR] age, 68 [57-77] years; 1764 [57.6%] men). There were 1584 tumors (51.7%) located in the antrum and 1539 stage 2 tumors (50.2%). On multivariable analyses among 1939 patients (owing to 137 patients with missing data for pCR and the exclusion of 988 patients with aCT and aCRT from pCR analysis), nCRT was associated with increased odds of pCR compared with NT, with the greatest odds ratio (OR) among all treatments (OR, 59.55; 95% CI, 10.63-333.56; P < .001). RTTU had the next highest OR (29.96; 95% CI, 2.92-307.53; P = .004). In multivariable analysis for OS among 3061 patients (owing to missing data for OS), CTTU was associated with decreased risk of death compared with NT (hazard ratio, [HR], 0.41; 95% CI, 0.35-0.48; P < .001), with the lowest HR, as was nCRT (HR, 0.48; 95% CI, 0.35-0.66; P < .001), with the next lowest HR. Median OS was greatest among patients treated with CTTU (53.9 months; 95% CI, 44.5-61.0 months), followed by nCRT (39.1 months; 95% CI, 26.9 months-not applicable) and aCT (36.1 months; 95% CI, 28.88-49.18 months), while 2-year OS rates were 65.6% (95% CI, 61.3%-69.5%) for CTTU, 63.6% (95% CI, 52.3%-73.0%) for nCRT, and 59.7% (95% CI, 54.2%-64.7%) for aCT.

CONCLUSIONS AND RELEVANCE

This study found that nCRT was associated with the highest pCR rate, while CTTU (ie, neoadjuvant or adjuvant therapy) was associated with the greatest OS.

Reevaluation of lymphovascular invasion in gastric cancer using endothelial markers D2-40 and EVG: Enhanced detection, better predictor of lymph node metastasis and biological aggressiveness

BACKGROUND AND OBJECTIVES

The diagnosis of lymphovascular invasion (LVI) is often inaccurate with routine histology. This study aimed to evaluate the use of immunohistochemistry (IHC) in detecting LVI and reevaluate the clinical implications of LVI in gastric cancer.

METHODS

This prospective unrandomized cohort study analyzed the rates of LVI positivity and its relevance with other clinicopathologic features.

RESULTS

Between November 2017 and April 2018, 558 patients undergoing curative gastrectomy were enrolled and assigned to the IHC group (n = 285) and hematoxylin-eosin group (n = 273). The use of IHC increased the rates of LVI positivity (60.8% vs. 43.3%, p < .001) and decreased the rates of undetermined LVI subtype (7.7% vs. 27.1%, p < .001). The LVI-negative patients identified by IHC had fewer lymph node metastases (16.8% vs. 34.6%, p = .002) and earlier pathological stage (p = .004) than those identified by routine histology. The LVI-positive patients identified by IHC had a higher percentage of perineural invasion (p = .019).

CONCLUSIONS

The use of endothelial markers significantly enhanced the detection of LVI. The LVI detected by IHC could be a better predictor of lymph node metastasis and biological aggressiveness in gastric cancer.

Downregulation of lncRNA HCP5 has inhibitory effects on gastric cancer cells by regulating DDX21 expression

LncRNA HCP5 has been confirmed to play crucial roles in many types of cancers. However, the role of lncRNA HCP5 in regulating the occurrence and development of gastric cancer (GC) remains unknown. In the current study, we aimed to investigate the precise effects of lncRNA HCP5 on cell proliferation, migration and invasion and molecular mechanisms in gastric cancer. Using RT-qPCR analysis, we found that lncRNA HCP5 was differentially expressed in GC cell lines. CCK-8, wound healing and transwell assay indicated that the proliferation, migration and invasion of gastric cancer cells were inhibited by downregulation of lncRNA HCP5 and lncRNA HCP5 overexpression exhibited the opposite effects in gastric cancer cells. Mechanistically, RNA binding protein immunoprecipitation and dual luciferase reporter assay confirmed the interaction between lncRNA HCP5 and DDX21. The effects of lncRNA HCP5 overexpression the proliferation, migration and invasion of GC cells were partly rescued by DDX21 silencing. Taken together, downregulation of lncRNA HCP5 exerted inhibitory effects on GC cell proliferation, migration and invasion through modulation of DDX21 expression, demonstrating the function of lncRNA HCP5 and DDX21 in GC progression.

A qualitative classification signature for post-surgery 5-fluorouracil-based adjuvant chemoradiotherapy in gastric cancer

BACKGROUND AND PURPOSE

Currently, 5-fluorouracil (5-FU)-based adjuvant chemoradiotherapy (ACRT) is a preferred regimen for post-surgery gastric cancer (GC). However, the survival outcome of 5-FU-based ACRT varies greatly among different GC patients. Thus, it is necessary to classify which patients may benefit from 5-FU-based ACRT.

MATERIALS AND METHODS

We collected 577 GC and 84 adjacent normal samples for training and 675 GC samples for validation. Based on the within-sample relative expression orderings (REOs) of gene expression levels, reversal gene pairs were selected, and the pairs correlating with overall survival (OS) of GC patients receiving 5-FU-based ACRT were identified as candidates. Finally, an optimized set of candidate gene pairs was selected as a classification signature in training data and validated in validation data.

RESULTS

A signature consisting of 34 gene pairs was identified in training data and validated in three independent datasets. The classified low-risk group had better OS than the classified high-risk group. We also analyzed the recurrent free survival or disease free survival (RFS/DFS) of the validation datasets, and the similar results were shown. Furthermore, although the signature was identified based on the OS of GC patients receiving ACRT, it was not a prognostic signature for patients treated with surgery alone, but may be a potential signature for 5-FU-based chemotherapy alone.

CONCLUSIONS

The signature can accurately classify GC patients who may benefit from 5-FU-based ACRT, which could aid clinicians in tailoring more effective GC treatments.