Gastric Cancer – Symptoms, Diagnosis and Modern Treatment

Gastric cancer, also known as stomach cancer, is one of the most common malignant tumors of the digestive system and represents a significant global public health problem. Although its incidence has declined in many developed countries over recent decades, the disease is often diagnosed at an advanced stage because early symptoms may be very mild or completely absent.

The good news is that significant advances have been made in treatment in recent years. Progress in surgery, chemotherapy, immunotherapy, and targeted therapies has led to better treatment outcomes and longer survival for many patients.

What Is Gastric Cancer?

Gastric cancer develops when cells in the lining of the stomach begin to divide uncontrollably and form a malignant tumor. In more than 90% of cases, it is an adenocarcinoma, which arises from the glandular cells of the stomach lining.

Less commonly, other types of stomach tumors may occur, such as gastrointestinal stromal tumors (GISTs), lymphomas, or neuroendocrine tumors. However, these are treated differently and are not classified as conventional gastric cancer.

How Common Is Gastric Cancer?

Gastric cancer is one of the most common malignant tumors in the world. According to the latest GLOBOCAN data for 2022, approximately 969,000 new cases were diagnosed, while nearly 660,000 people died from the disease. This makes gastric cancer the fifth most commonly diagnosed cancer and the fifth leading cause of cancer-related death worldwide.

The disease is significantly more common in East Asia, particularly in Japan, South Korea, and China, but high incidence rates are also observed in parts of Eastern Europe and South America. In countries such as Japan and South Korea, national gastroscopy screening programs are implemented, allowing a large number of tumors to be detected at an early stage, when the chances of cure are considerably higher.

Gastric cancer most commonly affects people over the age of 60 and is approximately twice as common in men as in women.

Risk Factors

The development of gastric cancer is influenced by a combination of genetic and environmental factors.

The most important risk factors include:

• Helicobacter pylori infection

• chronic atrophic gastritis

• intestinal metaplasia of the stomach

• smoking

• a diet rich in smoked, salted, and preserved foods

• excessive alcohol consumption

• obesity (particularly for tumors of the gastroesophageal junction)

• a positive family history

• certain hereditary syndromes (e.g., CDH1 mutations, Lynch syndrome, FAP)

It is important to emphasize that most people with one or more of these risk factors will never develop gastric cancer.

Symptoms of Gastric Cancer

In its early stages, gastric cancer often causes no symptoms, or the symptoms are very nonspecific.

Possible symptoms include:

• feeling full after eating small meals

• pain or discomfort in the upper abdomen

• loss of appetite

• nausea

• heartburn

• bloating

• unexplained weight loss

• fatigue

• anemia due to chronic bleeding

• vomiting blood or passing black stools in advanced disease

Since these symptoms are also common in many benign conditions, it is important to consult a doctor if they persist for a prolonged period or worsen.

How Is Gastric Cancer Diagnosed?

The most important diagnostic test is gastroscopy.

During the procedure, the doctor uses a camera to examine the esophagus, stomach, and the first part of the small intestine, and takes tissue samples (biopsies).

The definitive diagnosis is established by histopathological examination of the biopsy.

Once the diagnosis has been confirmed, it is necessary to determine the extent of the disease.

The most commonly performed investigations include:

• CT scan of the chest, abdomen, and pelvis

• endoscopic ultrasound (EUS) in selected patients

• PET/CT in selected situations

• diagnostic laparoscopy for locally advanced tumors when small peritoneal metastases are suspected

Molecular Tumor Analysis

In advanced gastric cancer, additional molecular analysis of the tumor tissue is now considered standard practice, as the results can significantly influence treatment selection.

The most important analyses include:

• HER2 status

• PD-L1 (CPS)

• MMR/MSI status

• other molecular analyses as needed (e.g., NGS)

The results of these analyses may enable the use of targeted therapies or immunotherapy.

Stages of Disease

Gastric cancer is classified into:

• localized disease

• locally advanced disease

• metastatic disease

The stage of the disease determines the treatment approach and prognosis.

Treatment of Gastric Cancer

Treatment is always planned by a multidisciplinary team that includes a surgeon, medical oncologist, gastroenterologist, radiologist, and pathologist.

Surgery

Surgical treatment offers the possibility of complete cure in selected patients.

Depending on the size and location of the tumor, the following procedures may be performed:

• partial gastrectomy

• total gastrectomy

• removal of the surrounding lymph nodes (D2 lymphadenectomy)

For very early-stage tumors, endoscopic resection without conventional surgery may be possible.

Perioperative Chemotherapy

For most patients with locally advanced gastric cancer, chemotherapy before and after surgery (so-called perioperative chemotherapy) is currently recommended.

The most commonly used regimen is FLOT, which has demonstrated better outcomes compared with older treatment regimens. It is administered as 4 cycles before surgery and 4 cycles after surgery.

The advantages of preoperative treatment include:

• tumor shrinkage

• a higher likelihood of complete tumor removal

• treatment of micrometastases that are not yet visible on imaging

Adjuvant Treatment

If the patient has not received chemotherapy before surgery, adjuvant chemotherapy or chemoradiotherapy may be indicated after surgery, depending on the histopathological findings and the extent of the surgical procedure.

Treatment of Metastatic Disease

In metastatic gastric cancer, the main goals of treatment are to prolong survival, control the disease, and preserve quality of life. In a small proportion of patients, depending on the molecular profile, complete cure may also be possible.

Treatment may include:

• chemotherapy

• immunotherapy

• targeted therapy

• supportive care

• palliative procedures when needed

Today, treatment for many patients is tailored according to the molecular characteristics of the tumor.

HER2-Positive Gastric Cancer

Approximately 15–20% of gastric adenocarcinomas overexpress the HER2 receptor.

For these patients, the standard first-line treatment includes a combination of chemotherapy and anti-HER2 therapy. In recent years, new anti-HER2 agents have also been introduced, further expanding treatment options after disease progression.

Examples of drugs used include trastuzumab and trastuzumab deruxtecan.

Immunotherapy

In recent years, immunotherapy has significantly changed the treatment of a subset of patients with gastric cancer.

The greatest benefit is seen in patients:

• with higher PD-L1 CPS scores

• with MSI-H (microsatellite instability-high) tumors

• in certain situations, HER2-positive patients in combination with other therapies

In appropriately selected patients, immunotherapy can significantly prolong survival.

Examples of drugs used include pembrolizumab and nivolumab.

Targeted Therapy

In addition to HER2-targeted therapies, numerous new targeted treatments are being developed for tumors with specific molecular alterations.

For this reason, molecular tumor profiling is becoming an increasingly important part of the management of advanced gastric cancer.

Nutrition During Treatment

Nutrition plays a very important role.

Many patients have already experienced weight loss or malnutrition at the time of diagnosis.

After gastric surgery, dietary adjustments are often necessary:

• more frequent, smaller meals

• adequate protein intake

• vitamin B12 supplementation after total gastrectomy

• nutritional supplements when needed

Working with a dietitian can significantly improve quality of life.

Prognosis

Prognosis depends on:

• the stage of the disease

• the possibility of complete surgical removal

• lymph node involvement

• the molecular characteristics of the tumor

• the patient's overall health

When gastric cancer is diagnosed at an early stage, the chance of complete cure is high.

In advanced disease, the goal of treatment is to prolong survival while maintaining the best possible quality of life. Thanks to new therapies, treatment outcomes today are significantly better than they were a decade ago.

When Should You See a Doctor?

If you have persistent digestive symptoms, unexplained weight loss, anemia, difficulty eating, or symptoms that last for several weeks, you should consult a doctor for further evaluation.

It is important to emphasize that most people with heartburn or stomach pain do not have gastric cancer. However, persistent or progressively worsening symptoms should always be medically evaluated.

Conclusion

Gastric cancer is a serious disease, but treatment options today are significantly better than they were just a few years ago. Surgery, modern chemotherapy, immunotherapy, and targeted therapies allow for an increasingly personalized approach to treatment, while molecular tumor analysis plays an ever-growing role in selecting the most appropriate therapy for each individual patient.

If you have been diagnosed with gastric cancer or would like a second opinion regarding your proposed treatment, you are welcome to contact us. At Anova Polyclinic, we treat patients according to the latest international guidelines from leading professional societies, including the European Society for Medical Oncology (ESMO) and the National Comprehensive Cancer Network (NCCN), while providing an individualized approach to every patient.

In addition to standard oncology treatments available within the Croatian healthcare system, we also provide guidance on other scientifically supported treatment options, including therapies available abroad when there is an appropriate medical indication. Our goal is to ensure that every patient has a comprehensive overview of all available treatment options in order to make a well-informed decision.

If you would like to schedule a consultation, obtain a second opinion, or develop an individualized treatment plan, please feel free to contact us. We will be happy to review your medical documentation together and help you choose the best possible treatment approach.