The American Society for Radiation Oncology (ASTRO) has published the first clinical guideline focused specifically on radiation therapy for gastric cancer, outlining evidence-based recommendations across disease stages. The guideline appears in Practical Radiation Oncology, ASTRO’s clinical practice journal.
Gastric tumors rank as the fifth most common cause of cancer incidence and death globally, with more than 30,000 new U.S. cases projected in 2025. While overall incidence has declined over the past 50 years, recent data indicate rising rates among middle-aged adults. Many cases are diagnosed at advanced stages, requiring coordinated care among radiation, surgical and medical oncology teams.
The guideline reviews advances in surgery, chemotherapy, immunotherapy and radiation therapy over the past decade. For resectable disease, perioperative chemotherapy regimens given before and after surgery remain recommended, with emerging evidence supporting added benefit from immunotherapy. Preoperative chemoradiation is recommended for patients who are not candidates for perioperative chemotherapy and may also be added for borderline resectable tumors to improve the likelihood of complete tumor removal.
Recommendations for unresectable or metastatic disease include definitive chemoradiation for nonmetastatic patients who decline surgery or are not surgical candidates. The guideline also addresses management of inoperable recurrent disease, palliative radiation therapy for symptom control, and conditional recommendations for treating limited metastases with local therapies combined with systemic treatment.
Treatment-planning guidance covers dosing, fractionation and appropriate treatment volumes for various disease stages. Recommendations also highlight the use of newer techniques, including intensity modulated radiation therapy, image guidance and respiratory management, to improve precision and treatment tolerance.
The guideline was developed by a multidisciplinary panel representing radiation oncology, medical oncology, surgical oncology, medical physics and patient advocacy. It involved a systematic review of research published from 2001 through mid-2025 and was created in collaboration with ASCO, ESTRO and the Society of Surgical Oncology. Endorsements were provided by ESTRO, SSO, the Royal Australian and New Zealand College of Radiologists and the American Radium Society.
Patient resources and additional educational materials are available through RTAnswers.org.
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