Diffusedlarge B cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin’s lymphoma, and its treatment is mainly chemotherapy, rituximab-based immunotherapy and radiation therapy. Because lymphoma is highly sensitive to radiation therapy, radiation therapy has been applied to its treatment for a long time. From the entire historical evolution of lymphoma treatment, it can be found that radiation therapy used to be the most dominant treatment for malignant lymphoma. With the continuous development of chemotherapeutic drugs, multi-drug combination chemotherapy has gradually become an important tool in the treatment of malignant lymphoma, and integrated radiotherapy and chemotherapy has also become the main strategy for the treatment of early diffuse large B-cell lymphoma. Development of radiotherapy strategy for diffuse large B-cell lymphoma Before the application of rituximab, classical studies such as SWOG8736, ECOG1484 and GELA’s LNH93-1 and LNH 93-4 can be found in the early aggressive non-Hodgkin’s lymphoma with predominantly diffuse large B-cell lymphoma, the results of which were not uniform. The results of the first two studies support the use of radiotherapy in stage I/II non-Hodgkin’s lymphoma, finding a survival benefit with the addition of radiotherapy, especially in the SWOG 8736 study, where 3 courses of CHOP regimen chemotherapy combined with 40-55 Gy of involved field radiotherapy resulted in higher 5-year OS and PFS than 8 courses of CHOP chemotherapy alone, with statistical differences. In contrast, the latter two studies conducted in Europe found that long-term survival was better with more intense chemotherapy regimens than with CHOP regimens chemotherapy 3 courses combined with radiotherapy, while no statistical difference was found between CHOP chemotherapy 4 courses combined with radiotherapy or not in elderly patients >60 years of age. However, in the SWOG 8736 study, cardiotoxicity and myelosuppression were found to be significantly higher with CHOP regimen chemotherapy course 8 than with CHOP chemotherapy course 3 combined with radiotherapy, and 28 of the 31 patients who did not complete the planned treatment failed to complete chemotherapy alone because of treatment toxicity. From the NCI SEER data, it was found that 5547 of 13420 cases of early DLBCL received radiotherapy and 7873 did not receive radiotherapy between 1998 and 2004, and the long-term follow-up results showed that the radiotherapy group outperformed the no-radiation group in terms of OS and DSS, and all P values were <0.001; in the analysis of the subgroup older than 60 years, it was also found that It was also found that radiotherapy brought benefits in OS and DSS in both stage I and stage II, and it was noted that the superiority of chemotherapy over radiotherapy in the GELA LNH 93 study was due to the increased toxicity of radiotherapy due to the large field of irradiation in this study, which prevented the benefits from being reflected in the patients treated with combination therapy. Prospective and retrospective studies in stage III/IV DLBCL have also found a survival benefit with the addition of radiotherapy in patients with large tumor loads (large masses over 250 px or 150 px) prior to chemotherapy or in those who achieved complete remission after chemotherapy. In the era of rituximab, the combination of chemotherapy and immunotherapy has become the standard, and the place of radiotherapy in this needs to be re-evaluated. The earliest combination of rituximab, CHOP chemotherapy and radiotherapy was seen in the SWOG0014 study. The investigators applied 4 courses of rituximab, 3 courses of CHOP regimen chemotherapy combined with 40-46 Gy of involved field radiotherapy and obtained excellent results. Compared to the SWOG 8736 study without rituximab, SWOG 0014 showed a further improvement in OS and PFS. However, SWOG 0014 was a small sample study that included only 60 patients. And the results of the study from M D Anderson Cancer Center were reported in JCO in 2010. It was a retrospective study that included 190 patients with stage I/II and 279 patients with stage III/IV DLBCL, of whom 327 patients received six or more courses of standard R-CHOP regimen chemotherapy and 142 patients received radiation therapy involving 30-39.6 Gy of field after achieving complete remission with chemotherapy. The investigators paired them in pairs, and a total of 74 pairs of patients received or did not receive radiotherapy after the same chemotherapy, 44 of which were early-stage patients. The results found that those who received radiotherapy had significantly better OS and PFS than those who did not receive radiotherapy. The results of the DUKE University study published in 2012 showed that in stage III/IV DLBCL, patients who achieved complete remission after chemotherapy were treated with a median dose of 25 Gy of radiation therapy and had better local control and EFS and OS than those without radiation therapy. Similarly, in the RICOVER-60 clinical trial, for the subgroup with tumors larger than 187.5 px, after 6 courses of R-CHOP14 chemotherapy, 306 patients received radiotherapy and 166 did not, at a dose of 36 Gy. The results revealed that for patients with large masses, their PFS at 18 months was 77% for those treated with radiotherapy and 67% for those not treated with radiotherapy, with a P value of 0.123, with no statistical difference. In contrast, among patients who did not achieve complete remission after chemotherapy, the PFS was higher and statistically significant for those treated with radiation than for those not treated with radiation. If CR was achieved after chemotherapy, there was no difference in PFS between the two. However, there was no difference in overall survival between radiotherapy and no radiotherapy. Thus, from the RICOVER-60 study, it was found that elderly patients who achieved CR or Cru after 6 courses of R-CHOP14 chemotherapy did not benefit from further radiotherapy; in patients who achieved PR after chemotherapy and had a large mass, radiotherapy improved EFS, PFS and OS; and the addition of radiotherapy did not increase treatment toxicity or treatment-related mortality. In conclusion, in the era of rituximab treatment, consolidation radiotherapy after chemotherapy in the treatment of early-stage diffuse large B-cell lymphoma still has a considerable place, but the population of benefit needs to be further subdivided; while in the treatment of stage III/IV DLBCL, radiotherapy remains palliative, but may further improve the efficacy. In the study published in 2010, it could be found that of 15 454 patients with stage I/II DLBCL, 6021 received radiotherapy and 9433 did not. In both univariate and multifactorial analyses, it was found that the cardiac-related morbidity and mortality rates were lower in those treated with radiotherapy compared with those without radiotherapy, P<0.0001. This may be due to the fact that patients without radiotherapy received more anthracycline-containing chemotherapy. < span=""> Changes in radiotherapy target area, dose, and radiotherapy technique Changes in radiotherapy target area The field of radiation therapy was total or sub-total lymph node irradiation in the earliest years of radiotherapy alone, which included bilateral cervical, axillary, mediastinal, retroperitoneal, iliac vessel, and inguinal lymph nodes as well as the spleen, with large fields and high doses, typically 45 Gy or more. The long-term toxicity associated with large and higher doses of radiotherapy cannot be ignored, mainly the increased incidence of cardiovascular disease and second primary tumors. Later, with the development of comprehensive treatment, the radiation field was gradually reduced and the dose was gradually lowered. The radiation field has been gradually reduced to regional field, involved field, and the common denominator of the evolved noderadiotherapy (INRT) proposed in Europe in 2007 and the involved site radiotherapy (ISRT) proposed in the United States in 2013 is the decreasing field. And it can be seen in the preliminary study that the reduction of the irradiation field did not cause an increase of local recurrence within the irradiated field and at the edge of the field, suggesting that the reduction of the radiotherapy scope does not affect local control. In a phase III randomized clinical trial published in 2011, a large sample of 1001 patients with low-grade malignant and moderate-to-high malignant non-Hodgkin’s lymphoma were randomized to the 24 Gy and 40-45 Gy dose groups, and 640 patients in the moderate-to-high malignant group were randomized to the 30 Gy and 40-45 Gy dose groups. dose groups. The results found no statistical difference in OS, PFS and LC between the low-dose group and the high-dose group, regardless of the degree of malignancy, suggesting that the dose of radiotherapy could be reduced to 30 Gy and 24 Gy, respectively, based on the previous dose of 40-45 Gy. However, the shortcomings of this study were that some patients were treated with radiotherapy alone or salvage radiotherapy, lacked detailed chemotherapy information, and most patients Rituximab was not applied. Radiotherapy techniques have been improving over the last decade or so, which has brought great changes in the overall radiotherapy. As the radiation field of lymphoma has been narrowed, the radiation field of lymphoma has become more and more similar to the radiation field of solid tumor, so 3D conformal and intensity modulation techniques are also commonly used in radiotherapy of lymphoma. In addition, the application of proton radiotherapy in lymphoma is being explored in recent years. The conformality and homogeneity of proton radiotherapy for treatment target coverage are better than photon lines, and the dose to normal tissues is extremely low. In a study of proton radiotherapy for Hodgkin’s lymphoma, the dose to the heart and its sub-structures was analyzed and it was found that proton-modulated radiotherapy could greatly reduce the dose to the heart and its sub-structures, thus protecting the heart and greatly reducing the incidence of cardiovascular disease, which has been criticized as a long-term toxicity of radiotherapy. In addition, the respiratory control device reduces the effect of respiration on the mobility of the radiotherapy target area to the lowest possible level, thus reducing the dose to normal tissues, especially the heart and lungs. In summary, the continuous reduction of the radiotherapy target area and dose, as well as the development of radiotherapy technology, have led to a further reduction in the toxicity of radiotherapy, while ensuring the efficacy of the treatment.