¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography for the evaluation of bone metastasis in patients with gastric cancer

18 F-FDG-avid Myelophthisis : A Caveat Unveiling Occult Signet-ring Cell Gastric Carcinoma

Disseminated 18 F-FDG-avid intraosseous lesions and clumps of malignant signet-ring cells on subsequent bone marrow aspirate were detected upon investigation of a 58-year-old man with intolerable bone pain, normocytic anemia, and elevated serum alkaline phosphatase. Immunohistochemistry and gastroscopic biopsy confirmed mucin-rich signet-ring cell adenocarcinoma [signet-ring cell gastric carcinoma (SRGC)]. Intriguingly, synchronous bone secondaries from SRGC tend to be hypermetabolic, regardless of the primary tumor 18 F-FDG-negativity, insinuating a reverse heterogeneity of tumor molecular biology. The identification of 18 F-FDG-avid myelophthisis on the setting of bone pain constitutes a caveat for suspicion of cancerous lesions from SRGC and should urge for bone marrow biopsy to improve treatment implications.

Bone Metastasis From Gastric Adenocarcinoma-What Are the Risk Factors and Associated Survival? A Large Comprehensive Population-Based Cohort Study

Background

While bone metastasis is not common in gastric adenocarcinoma (GaC), it can have important impacts on prognosis. This large cohort study aimed at exploring factors associated with bone metastasis in GaC and investigating the time-dependent cumulative mortalities and prognostic factors in GaC patients with bone metastasis at the population level.

Methods

Data on patients with GaC diagnosed in 2010–2016 were retrieved from a large population-based database. We explored factors associated with bone metastasis using the multivariable-adjusted logistic model. We then calculated the time-dependent cancer-specific mortalities in GaC patients with bone metastasis using the cumulative incidence function and compared mortalities across subgroups using Gray’s test. We further assessed factors associated with mortality using the multivariable-adjusted Fine–Gray subdistribution hazard model.

Results

Together 11,072 eligible patients with metastatic GaC were enrolled, which comprised 1,511 (14%) people with bone metastasis and 9,561 (86%) with other metastasis, encompassing 6,999 person-years of follow-up. Bone metastasis was more frequently detected in 2014 or later, in younger patients, in patients with gastric cardia cancers, in people with signet-ring cell carcinoma, and in those with poorly differentiated/undifferentiated cancers; it was less commonly observed in black patients. Bone metastasis was associated with more frequent brain and lung metastases. The median survival of patients with bone metastasis was 4 months; the 6-month and 3-year cancer-specific cumulative mortalities were 56% and 85%, respectively. In patients receiving chemotherapy, American Indians/Alaskan Natives, patients with gastric antrum/pylorus cancers, and those with positive lymph nodes had higher mortality risks, while those undergoing resection had lower mortality hazards.

Conclusion

In GaC patients, bone metastasis was associated with various clinicopathologic factors including age, ethnicity, tumor location, histology, differentiation, and metastasis to other sites. Patients with bone metastasis had poor prognosis which was associated with ethnicity, tumor location, lymph node involvement, and treatment. Our findings provide important hints for tailed patient management and for further mechanistic investigations.

A Diagnostic Nomogram Based on 18F-FDG PET/CT for Bone Metastasis of Gastric Cancer

Purpose: To develop an effective diagnostic model for bone metastasis of gastric cancer by combining ¹⁸F-FDG PET/CT and clinical data.

Materials and Methods: A total of 212 gastric cancer patients with abnormal bone imaging scans based on ¹⁸F-FDG PET/CT were retrospectively enrolled between September 2009 and March 2020. Risk factors for bone metastasis of gastric cancer were identified by multivariate logistic regression analysis and used to create a nomogram. The performance of the nomogram was evaluated by using receiver operating characteristic curves and calibration plots.

Results: The diagnostic power of the binary logistic regression model incorporating skeleton-related symptoms, anemia, the SUVmax of bone lesions, bone changes, the location of bone lesions, ALP, LDH, CEA, and CA19-9 was significantly higher than that of the model using only clinical factors (p = 0.008). The diagnostic model for bone metastasis of gastric cancer using a combination of clinical and imaging data showed an appropriate goodness of fit according to a calibration test (p = 0.294) and good discriminating ability (AUC = 0.925).

Conclusions: The diagnostic model combined with the ¹⁸F-FDG PET/CT findings and clinical data showed a better diagnosis performance for bone metastasis of gastric cancer than the other studied models. Compared with the model using clinical factors alone, the additional ¹⁸F-FDG PET/CT findings could improve the diagnostic efficacy of identifying bone metastases in gastric cancer.

Small early gastric cancer with synchronous bone metastasis: A case report

Bone metastasis during the early stages of gastric cancer is rare, and synchronous bone metastasis is even less common. The present report outlines a case of a small early gastric cancer, which was detected due to bone metastasis. A 63-year-old man was referred to Fukuyama Medical Center with back pain and anorexia of 2 weeks' evolution. MRI revealed multiple metastatic lesions in the thoracic and spinal bone. Fluorodeoxyglucose positron emission tomography revealed focal uptake in the lesser curvature of the stomach and in the spinal bone, pelvic and thigh bone, but uptake was not detected in the stomach. Esophagogastroduodenoscopy revealed a 10 mm slightly elevated lesion with a central depression in the middle-third of the stomach. Endoscopic ultrasonography confirmed that the tumor was confined to the mucosa. A biopsy specimen acquired from the gastric lesion indicated signet-ring cell carcinoma, and the specimen acquired from the lumbar spine revealed cell aggregation such as that found in signet-ring cell carcinoma. The patient received first-line chemotherapy with S-1 and cisplatin, and second-line chemotherapy with nab-paclitaxel. However, the patient died 120 days after consultation at Fukuyama Medical Center.

PET/Computed Tomography and Precision Medicine: Gastric Cancer

Gastric cancer is a disease with low survival rates and high morbidity, requiring accurate and prompt diagnosis and treatment. Although limited in the evaluation of the primary tumor as such, the metabolic information of primary tumors in an ¹⁸F-FDG PET/CT study can assist in surgical and treatment planning and differentiating gastric cancers. It detects nodal disease with good specificity and positive predictive value, thus enabling appropriate therapy for individual patients. It provides valuable information about distant metastases, altering therapy decisions. It has reasonably good performance in detecting recurrent disease and in the follow-up of patients.

Multi-technique imaging of bone metastases: spotlight on PET-CT

There is growing evidence that molecular imaging of bone metastases with positron-emission tomography (PET) can improve diagnosis and treatment response assessment over current conventional standard imaging methods, although cost-effectiveness has not been assessed. In most cancer types, 2-[(18)F]-fluoro-2-deoxy-d-glucose ((18)F-FDG)-PET is an accurate method for detecting bone metastases. For example, in breast cancer, combined (18)F-FDG-PET and computed tomography (CT) is more sensitive at detecting bone metastases than (99m)technetium (Tc)-labelled diphosphonate planar bone scintigraphy (BS) and there is increasing evidence to support the use of serial (18)F-FDG-PET for the assessment of osseous response to treatment. Preliminary data suggest improved diagnostic accuracy of (18)F-FDG-PET-CT in a number of other malignancies including lung, thyroid, head and neck, gastro-oesophageal cancers, and osteosarcoma. As a bone-specific tracer, there is accumulating evidence to support the use of sodium (18)F-fluoride ((18)F-NaF) PET-CT in the diagnosis of skeletal metastases in breast and prostate cancer, although relatively little data are available to support its use for assessment of treatment response. In prostate cancer, (11)C-choline and (18)F-choline PET-CT have better specificities than (18)F-NaF-PET-CT, but equivalent sensitivities in the detection of bone metastases. We review the current literature for staging and response assessment of bone metastases in different cancers.

(18)F-FDG PET/CT versus bone scintigraphy in the follow-up of gastric cancer

A 53-year-old patient underwent a positron emission tomography/computed tomography with 2-fluoro-2-deoxy-d-glucose ((18)F-FDG PET/CT) in the suspicious of gastric tumor recurrence (mediastinal and abdominal lymph nodes). PET/CT identified only an area of (18)F-FDGuptake in the twelfth thoracic vertebrae. Unexpectedly, a bone scintigraphy revealed many "hot" spots changing the diagnosis (single metastasis versus plurimetastatic disease) and impacting on patient's management.

Modern imaging techniques for preoperative detection of distant metastases in gastric cancer

A substantial portion of patients with newly diagnosed gastric cancer has distant metastases (M1 disease). These patients have a very poor prognosis and it is generally accepted that they should be treated with noncurative intent. Because it dramatically changes prognosis and treatment plans, it is very important to diagnose distant metastases. In this article, the definition, pathways, incidence and sites of distant metastases in gastric cancer are described. Subsequently, the current performance of imaging in detecting distant metastases in newly diagnosed gastric cancer is outlined and future prospects are discussed.

Targeting mast cells in gastric cancer with special reference to bone metastases

Bone metastases from gastric cancer (GC) are considered a relatively uncommon finding; however, they are related to poorer prognosis. Both primary GC and its metastatic progression rely on angiogenesis. Several lines of evidence from GC patients strongly support the involvement of mast cells (MCs) positive to tryptase (MCPT) in primary gastric tumor angiogenesis. Recently, we analyzed infiltrating MCs and neovascularization in bone tissue metastases from primary GC patients, and observed a significant correlation between infiltrating MCPT and angiogenesis. Such a finding suggested the involvement of peritumoral MCPT by infiltrating surrounding tumor cells, and in bone metastasis angiogenesis from primary GC. Thus, an MCPT-stimulated angiogenic process could support the development of metastases in bone tissue. From this perspective, we aim to review the hypothetical involvement of tumor-infiltrating, peritumoral MCPT in angiogenesis-mediated GC cell growth in the bone microenvironment and in tumor-induced osteoclastic bone resorption. We also focus on the potential use of MCPT targeting agents, such as MCs tryptase inhibitors (gabexate mesylate, nafamostat mesylate) or c-KitR tyrosine kinase inhibitors (imatinib, masitinib), as possible new anti-angiogenic and anti-resorptive strategies for the treatment of GC patients affected by bone metastases.