Lymphoma, Gastric

Second most common gastric malignancy, 3–5% of gastric cancers

More than 95% are non-Hodgkin B-cell lymphomas consisting of mucosa-associated lymphoid tissue (MALT) lymphoma and diffuse large B-cell lymphoma

Gastric T-cell lymphoma, associated with HTLV-1 infection, is rare and makes up 7% of primary gastric lymphomas

Infection with Helicobacter pylori is an important risk factor for primary gastric lymphoma

> 90% of low-grade primary gastric lymphomas are associated with H pylori

Dyspepsia

Abdominal pain

Weight loss

Upper GI bleeding

Anemia

Endoscopic ultrasonography is the most sensitive test for determining the level of invasion and presence of perigastric lymphadenopathy

CT scanning of chest, abdomen, and pelvis useful in staging

For patients with diffuse large B-cell lymphomas involving the stomach, the following may be required for staging and management

• Combination PET-CT imaging

• Bone marrow biopsy with aspirate

• Tumor lysis laboratory tests

• Viral hepatitis and HIV serologies

The Lugano staging system is most frequent used for gastric MALT lymphomas

• Stage I is confined to the GI tract

• Stage II involves local or regional lymph nodes

• Stage IIE has invasion of adjacent organs or tissues

• Stage IV has distant metastases

• There is no stage III

Primary low-grade gastric lymphomas

• Usually localized to the stomach wall (stage I) or perigastric lymph nodes (stage IIE₁)

• Have an excellent prognosis

After successful H pylori eradication, complete lymphoma regression occurs in ~75% of cases of stage IE low-grade lymphoma and in ~55% with stage IIE low-grade lymphoma

MALT-type lymphomas

• Patients who are not infected with H pylori or do not respond to eradication therapy can be treated successfully with radiation therapy (or with rituximab if not a candidate for radiation)

• However, hepatitis B reactivation can occur with rituximab, including fatal cases of fulminant hepatitis

• Surgical resection is no longer recommended because of a low risk of perforation with either radiation therapy or chemotherapy

• Long-term survival of primary gastric lymphoma for stage I is > 90% and for stage II, 35–65%

Diffuse large B-cell lymphoma

• Surgery has been associated with a better prognosis than conservative treatment

• Usually presents at an advanced stage with widely disseminated disease and is treated according to stage and subtype of lymphoma