Stomach Cancer: Early Symptoms, Diagnosis, and Modern Treatment Methods

Introduction: What is stomach cancer?

Stomach cancer is a serious oncological disease that, unfortunately, is often diagnosed at late stages due to the non-specific nature of early symptoms. However, timely detection and adequate treatment significantly improve the prognosis. Understanding the first signs, modern diagnostic methods, and available therapeutic strategies is the key to successfully combating this ailment.

First signs and symptoms of stomach cancer: What to look out for?

Symptoms of stomach cancer in the early stages are often mild or resemble manifestations of other gastrointestinal diseases, which complicates timely diagnosis. Nevertheless, there are signs that should raise concern:

• Persistent upper abdominal pain: One of the most frequent symptoms, which can be mistaken for common indigestion or gastritis [1], [2], [4].
• Nausea and loss of appetite: These symptoms may gradually worsen, leading to weight loss [3].
• Vomiting: Especially after eating, often associated with delayed stomach emptying or obstruction [4].
• Anemia: Can be the result of chronic blood loss from the tumor, manifesting as weakness, pallor, and shortness of breath [3], [4].
• Heartburn and belching: Non-specific symptoms that may indicate digestive problems.
• Hiccups: In rare cases, this can be one of the manifestations, especially when certain areas of the stomach are affected [6].
• Changes in the mucous membrane: In some cases, a precursor to gastric lymphoma may be "chicken skin-like gastritis" – nodular protrusions in the antrum and body of the stomach, which can be observed long before the development of a malignant process [1].

It is important to remember that the presence of one or more of these symptoms does not necessarily mean cancer is present, but it is a reason to consult a doctor and undergo an examination.

Diagnosis of stomach cancer: From endoscopy to biopsy

Accurate diagnosis of stomach cancer requires a comprehensive approach. Key methods include:

• Endoscopy (gastroscopy): This is the primary method that allows for a visual assessment of the stomach lining, detecting ulcers, tumors, or other suspicious changes [1], [2], [3], [4]. During endoscopy, a doctor can identify signs such as deep ulcers with irregular bases and edges, as well as changes in the color and structure of the mucosa [1].
• Biopsy and histological examination: Taking tissue samples during endoscopy for microscopic analysis is a crucial step. Pathomorphological examination allows for the determination of the tumor type (e.g., adenocarcinoma, squamous cell carcinoma, lymphoma) and its degree of malignancy [1], [2], [3], [4], [6].
• Immunohistochemical (IHC) examination: Used for more precise tumor classification, especially in complex cases. For example, in primary gastric squamous cell carcinoma (PGSCC), IHC markers such as CK5/6, P40, and P63 help distinguish it from adenocarcinoma, which may have similar initial manifestations [2]. The adequacy and depth of the biopsy are critically important, as a limited sample can lead to an incorrect diagnosis [2].
• Instrumental imaging methods: Computed tomography (CT), positron emission tomography (PET-CT), and ultrasound (US) of the abdomen and pelvis are used to assess tumor spread and detect metastases in lymph nodes and distant organs, such as the liver [6].

It is also important to consider differential diagnosis. For example, chronic gastritis caused by Helicobacter pylori or the presence of the bacterium Sarcina ventriculi, which is often associated with delayed gastric emptying, can mimic cancer symptoms or coexist with it [1], [4]. It is also necessary to exclude other causes of gastrointestinal symptoms, such as ulcers caused by primary hyperparathyroidism [7] or gastritis associated with immunotherapy or chemotherapy [3], [8].

Modern approaches to treating stomach cancer

Treatment for stomach cancer depends on the stage of the disease, the type of tumor, the patient's general condition, and the presence of comorbidities. Modern oncology offers comprehensive approaches:

• Surgical intervention: Radical gastrectomy (removal of part or all of the stomach) remains the primary treatment method in early stages, especially for localized tumors [6].
• Chemotherapy: Used before (neoadjuvant), after (adjuvant), or as palliative treatment for inoperable or metastatic forms of cancer. Various regimens are used, for example, combinations of capecitabine and oxaliplatin. Some drugs, such as zolbetuximab, can be effective in tumors expressing the claudin-18 protein [3]. However, chemotherapy can cause side effects, including gastritis [3].
• Targeted therapy: Aimed at specific molecular targets in tumor cells. For example, zolbetuximab targets claudin-18 [3].
• Immunotherapy: Drugs that block immune checkpoint pathways (e.g., PD-1 inhibitors) help the patient's own immune system recognize and destroy cancer cells. Immunotherapy can be effective even in advanced forms of cancer, but sometimes causes immune-related side effects, such as gastritis and duodenitis [5], [8].
• Radiation therapy: Can be used to shrink a tumor before surgery, destroy residual cancer cells, or relieve symptoms in advanced disease. In combination with immunotherapy and granulocyte-macrophage colony-stimulating factor (PRaG therapy), radiation therapy has shown impressive results, leading to a complete pathological response even in refractory metastatic hepatoid adenocarcinoma of the stomach [5].

For elderly patients or those in poor physical condition, a palliative treatment plan aimed at improving quality of life and relieving symptoms may be chosen [2].

Rare forms and features of stomach cancer

Stomach cancer is not a homogeneous disease, and there are rare forms that require a special approach:

• Primary gastric squamous cell carcinoma (PGSCC): A rare histological type that can be misdiagnosed as adenocarcinoma in the initial stages. It requires a deep biopsy and specific immunohistochemical examination for accurate confirmation [2].
• Hepatoid adenocarcinoma of the stomach (HAS): An even rarer and more aggressive subtype with a poor prognosis. However, even in such cases, new combined approaches, such as PRaG therapy, can lead to complete tumor regression [5].
• Gastric lymphoma: Malignant lymphoma can develop in the stomach, sometimes after a long course of gastritis associated with H. pylori, and even after its eradication [1].
• Concomitant malignant neoplasms: These are extremely rare, but cases of simultaneous development of stomach cancer and other primary malignant tumors, such as primary hepatic angiosarcoma, are possible. This underscores the importance of thorough diagnosis to avoid mistaking a second tumor for a metastasis [6].

Understanding these features allows doctors to more accurately diagnose and individualize treatment for each patient.

Sources

• 1. Persistent upper gastrointestinal symptoms after Helicobacter pylori eradication: malignant lymphoma after "chicken skin-like gastritis". (Revista espanola de enfermedades digestivas, 2025) https://pubmed.ncbi.nlm.nih.gov/38989877/
• 2. Overcoming diagnostic errors in primary gastric squamous cell carcinoma: the need for adequate sampling in an elderly patient, a case report. (Frontiers in oncology, 2025) https://pubmed.ncbi.nlm.nih.gov/41333217/
• 3. Zolbetuximab-associated gastritis: a case report of a patient with prolonged gastrointestinal symptoms. (Gastric cancer : official journal of the International Gastric Cancer Association and the Japanese Gastric Cancer Association, 2025) https://pubmed.ncbi.nlm.nih.gov/40178693/
• 4. Sarcina ventriculi: an incidental finding or a byproduct of a more serious underlying disease? (Radiology case reports, 2026) https://pubmed.ncbi.nlm.nih.gov/42437153/
• 5. Case report: Complete pathological response to PRaG therapy in an elderly patient with refractory metastatic gastric cancer. (Frontiers in oncology, 2025) https://pubmed.ncbi.nlm.nih.gov/41626177/
• 6. Concomitant gastric carcinoma and primary hepatic angiosarcoma in a patient: a case report. (Open life sciences, 2025) https://pubmed.ncbi.nlm.nih.gov/41377863/
• 7. Two rare manifestations of primary hyperparathyroidism: paralysis and peptic ulcer bleeding. (Endocrinology, diabetes & metabolism case reports, 2017) https://pubmed.ncbi.nlm.nih.gov/28721219/
• 8. Rare occurrence of immunotherapy-associated gastritis and duodenitis in a single tertiary medical center: a diagnostic challenge. (The oncologist, 2025) https://pubmed.ncbi.nlm.nih.gov/41092065/

Disclaimer: The information provided in this article is for reference purposes only and cannot replace professional consultation, diagnosis, or treatment provided by a qualified medical professional. Always consult a doctor regarding any questions about your health.