Given the favourable prognosis of patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma, treatment-related toxicity should be minimised. We aimed to evaluate the efficacy of 4 Gy radiotherapy given in a response-adapted approach. We conducted a single-centre, single-arm, prospective trial at MD Anderson Cancer Center (Houston, TX, USA) of response-adapted ultra-low-dose radiotherapy. Eligible patients were 18 years or older and had newly diagnosed or relapsed -negative gastric MALT lymphoma, with stage I–IV disease. Given the expected low toxicity profile of treatment, performance status was not an exclusion criterion. Patients received external beam photon-based radiotherapy for a total dose of 4 Gy in two fractions. Patients with a complete response to 4 Gy via endoscopy and imaging at 3–4 months were observed; patients with a partial response were re-evaluated in 6–9 months. Residual disease at 9–13 months or stable or progressive disease at any time required additional treatment with 20 Gy. The primary endpoint was gastric complete response at 1 year (second evaluation timepoint) after 4 Gy treatment. All analyses were performed as intention to treat. This trial is registered at () and is complete and closed to enrolment. Between March 27, 2019, and Oct 12, 2021, we enrolled 24 eligible patients. The median age of participants was 67 years (IQR 58–74; range 40–85); 15 (63%) were female and nine (37%) male; 18 (75%) were White, four (17%) Asian, and two (8%) Hispanic; 20 (83%) had stage I disease, one (4%) stage II, and three (13%) stage IV. Median follow-up time was 36 months (IQR 26–42). 20 patients (83%) had a complete response to 4 Gy (16 at 3–4 months, four at 9–13 months); two patients received 20 Gy for symptomatic stable disease at 3–4 months and two for residual disease at 9–13 months; all had a complete response. The 3-year local control rate was 96% (95% CI 88–100), with one local relapse at 14 months after 4 Gy radiotherapy salvaged successfully with 20 Gy. One patient with stage IV disease had a distant relapse. The most common adverse events were grade 1 nausea (nine [38%] of 24 patients who received 4 Gy and two [50%] of four patients who received 20 Gy) and grade 1 abdominal pain (five [21%] of 24 and zero of four, respectively). No grade 3 or worse adverse events were noted, including no treatment-related deaths. Most patients had a complete response after 4 Gy radiotherapy; all who required an additional 20 Gy had a complete response within 12 months. This response-adapted strategy could be used to select patients who would benefit from additional radiotherapy and spare others potential associated toxicity. National Cancer Institute.

中文翻译：

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适应反应的超低剂量 4 Gy 放射作为胃 MALT 淋巴瘤的确定性治疗：单中心试点试验


鉴于胃粘膜相关淋巴组织（MALT）淋巴瘤患者的良好预后，应尽量减少治疗相关的毒性。我们的目的是评估采用适应反应的方法进行 4 Gy 放射治疗的疗效。我们在 MD 安德森癌症中心（美国德克萨斯州休斯顿）进行了一项单中心、单组前瞻性试验，研究适应反应的超低剂量放射治疗。符合资格的患者年龄为 18 岁或以上，患有新诊断或复发的阴性胃 MALT 淋巴瘤，且疾病处于 I-IV 期。鉴于治疗的预期低毒性特征，表现状态不是排除标准。患者接受基于外束光子的放射治疗，总剂量为 4 Gy，分两次进行。观察 3-4 个月时通过内窥镜检查和成像对 4 Gy 完全缓解的患者；部分缓解的患者在 6-9 个月内重新评估。 9-13 个月内的残留疾病或任何时间的稳定或进展疾病需要 20 Gy 的额外治疗。主要终点是 4 Gy 治疗后 1 年（第二个评估时间点）时胃部完全缓解。所有分析均按意向治疗进行。该试验已在 () 处注册，并且已完成并已停止招募。 2019年3月27日至2021年10月12日期间，我们招募了24名符合条件的患者。参与者的中位年龄为 67 岁（IQR 58-74；范围 40-85）； 15 名 (63%) 为女性，9 名 (37%) 为男性； 18 名 (75%) 为白人，四名 (17%) 为亚裔，两名 (8%) 为西班牙裔； 20 人 (83%) 患有 I 期疾病，1 人 (4%) 患有 II 期疾病，3 人 (13%) 患有 IV 期疾病。中位随访时间为 36 个月（IQR 26-42）。 20 名患者 (83%) 对 4 Gy 产生完全缓解（16 名患者在 3-4 个月时，4 名患者在 9-13 个月时）；两名患者在 3-4 个月时因症状稳定疾病接受 20 Gy 治疗，两名患者在 9-13 个月时因残留疾病接受 20 Gy 治疗；所有人都得到了完整的回应。 3年局部控制率为96%（95% CI 88-100），4 Gy放疗后14个月有1例局部复发，20 Gy成功挽救。一名患有 IV 期疾病的患者出现远处复发。最常见的不良事件是 1 级恶心（接受 4 Gy 的 24 名患者中的 9 名 [38%]，接受 20 Gy 的 4 名患者中的 2 名 [50%]）和 1 级腹痛（24 名接受 4 Gy 治疗的患者中，有 5 名 [21%]）分别为四中的零）。没有发现 3 级或更严重的不良事件，包括没有与治疗相关的死亡。大多数患者在 4 Gy 放疗后获得完全缓解；所有需要额外 20 Gy 的患者均在 12 个月内得到完全缓解。这种适应反应的策略可用于选择能够从额外放疗中受益并避免其他潜在相关毒性的患者。国家癌症研究所。