Minimal residual disease profiling predicts pathological complete response in esophageal squamous cell carcinoma.

Accurate presurgical prediction of pathological complete response (pCR) can guide treatment decisions, potentially avoiding unnecessary surgeries and improving the quality of life for cancer patients. We developed a minimal residual disease (MRD) profiling approach with enhanced sensitivity and specificity for detecting minimal tumor DNA from cell-free DNA (cfDNA). The approach was validated in two independent esophageal squamous cell carcinoma (ESCC) cohorts. In a cohort undergoing neoadjuvant, surgical, and adjuvant therapy (NAT cohort), presurgical MRD status precisely predicted pCR. All MRD-negative cases (10/10) were confirmed as pCR by pathological evaluation on the resected tissues. In contrast, MRD-positive cases included all the 27 non-pCR cases and only one pCR case (10/10 vs 1/28, P < 0.0001, Fisher's exact test). In a definitive radiotherapy cohort (dRT cohort), post-dRT MRD status was closely correlated with patient prognosis. All MRD-negative patients (25/25) remained progression-free during the follow-up period, while 23 of the 26 MRD-positive patients experienced disease progression (25/25 vs 3/26, P < 0.0001, Fisher's exact test; progression-free survival, P < 0.0001, log-rank test). The MRD profiling approach effectively predicted the ESCC patients who would achieve pCR with surgery and those likely to remain progression-free without surgery. This suggests that the cancer cells in these MRD-negative patients have been effectively eliminated and they could be suitable candidates for a watch-and-wait strategy, potentially avoiding unnecessary surgery.

Case report: Radiotherapy plus pneumococcal conjugate vaccine stimulates abscopal immune response in a patient with ALK+ NSCLC.

Most patients with anaplastic lymphoma kinase-positive (ALK+) non-small-cell lung cancer (NSCLC) could benefit from the treatment with selected tyrosine kinase inhibitors (TKIs) for a period of time, but almost inevitably progress due to drug resistance. It was reported that these patients were generally unresponsive to immune-based therapies. Here, we reported that stereotactic body radiotherapy (SBRT) combined with pneumococcal conjugate vaccine (PCV) produced excellent therapeutic outcomes in a patient after multiple lines of TKI treatment. The patient's metastasis lesion experienced regression after SBRT for lumbar spine. Unexpectedly, the patient also experienced an abscopal complete pathological response (CPR) just after combination use of SBRT and PCV. Biopsy analysis indicated that the primary lung lesion was map-like necrotic and infiltrated by tumor-infiltrating lymphocytes (TILs), and multifocal granulomas and early tertiary lymphoid structures (TLS) were formed. Our case reported that radiotherapy plus PCV could specifically stimulate immune response and remodel the tumor immune microenvironment in TKI-resistant NSCLC, which may provide a new perspective for future immunotherapy in this challenging clinical situation.

[Therapeutic efficacy of three-dimensional conformal radiation therapy for patients with locally advanced non-small cell lung cancer].

OBJECTIVE: To compare the treatment results of three-dimensional conformal radiotherapy (3D-CRT) and conventional radiotherapy (2D) for patients with locally advanced non-small-cell lung cancer (NSCLC). METHODS: Five hundred and twenty seven patients with stage III NSCLC treated between Jan 2000 and Dec 2006 were included in this study. Among them, 253 cases were treated with 3D-CRT, and 274 with conventional radiotherapy. In the 3D group, 159 (62.8%) patients received chemoradiotherapy, 77 with total radiotherapy dose of > 60 Gy, 49 with 50 - 60 Gy. In the 2D group, 127 (46.4%) patients received chemoradiotherapy, 48 with total radiotherapy dose of > 60 Gy, 75 with 50 - 60 Gy. RESULTS: The 1-, 3-, 5-year overall survival rates (OS) and median survival time for patients treated with 3D-CRT were 73.3%, 26.1%, 14.4% and 20.1 months, respectively, and that of patients treated with 2D radiotherapy were 61.0%, 13.8%, 8.0% and 15.6 months, respectively (P = 0.002). The 1-, 3-, 5-year cause-specific survival rates (CSS) were 79.0%, 33.3%, and 20.8% for the 3D group and 65.1%, 16.7%, 11.2%, respectively, for the 2D group (P = 0.000). The 1-, 3-, and 5-year locoregional control rates were 71.6%, 34.3% and 31.0% for patients treated with 3D radiotherapy and 57.3%, 22.1% and 19.2%, respectively, for patients treated with 2D treatment (P = 0.002). The results of multivariate analysis showed that 3D-CRT, KPS, clinical tumor response and pretreatment hemoglobin level were independently associated with increased OS and CSS. No statistically significant differences were found between the radiation complications in the two groups. CONCLUSIONS: The results of our study demonstrate that 3D-conformal radiotherapy improves the survival rate in patients with stage III NSCLC compared with that of 2D radiation therapy.

[Thoracic radiation therapy improves the prognosis for patients with extensive stage small-cell lung cancer].

OBJECTIVE: To evaluate the effect of thoracic radiation therapy (TRT) on patients with extensive stage small-cell lung cancer (SCLC). METHODS: One hundred and fifty-four patients with extensive stage SCLC treated in our department between January 2003 and December 2006 were enrolled in this study. Eighty nine patients received chemotherapy and thoracic radiation therapy (ChT/TRT), and 65 patients were treated with chemotherapy alone (ChT without TRT). The chemotherapy was CE (carboplatin and etoposide), PE (cisplatin and etoposide) or CAO (CTX, ADM and VCR) regimens. The total dose of thoracic irradiation was 40-60 Gy with 1.8 - 2.0 Gy per fraction. RESULTS: For the whole group, the median survival time (MST) was 13.7 months, the 2-year and 5-year overall survival rates were 27.9% and 8.1%, respectively. The MST, overall survival rates at 2 years and 5 years in the ChT/TRT group and ChT without TRT group were 17.2 months, 36.0%, 10.1% and 9.3 months, 16.9%, 4.6%, respectively (P = 0.001). The median progression-free survival (PFS) for all patients was 8.0 months, the 2-year and 5-year PFS were 13.6% and 8.2%, respectively. The median PFS, 2-year and 5-year PFS in the ChT/TRT group and ChT without TRT group were 10.0 months, 17.4%, 10.5% and 6.2 months, 9.8%, 4.9%, respectively (P < 0.001). The incidence of intra-thoracic local failure was 29.6% in the ChT/TRT group and 70.0% in the ChT/without TRT group (P = 0.000). CONCLUSIONS: Chemotherapy plus thoracic radiation therapy can improve the overall survival, progress free survival and reduce local regional failure rate in patients with extensive stage SCLC compared with that by chemotherapy alone.

[The association between polymorphism of transforming growth factor-ß1 and radiochemotherapy response and survival in esophageal squamous cell carcinoma patients].

OBJECTIVE: To evaluate the association between polymorphism of transforming growth factor-ß1 (TGF-ß1)-509C/T and radiochemotherapy response and survival in esophageal squamous cell carcinoma (ESCC) patients. METHODS: The genotype of TGF-ß1-509C/T was detected by polymerase chain reaction-based restriction fragment length polymorphism assay (PCR-RFLP) in 230 ESCC patients receiving radiotherapy alone or in combination with chemotherapy. Unconditional multivariate logistic regression analysis was done to estimate adjusted odds ratios (ORs) along with the corresponding 95% confidence intervals (CIs) for the polymorphism and radiochemotherapy response. The associations between overall survival time or hazard ratio (HR) of ESCC patients and genetic variation or the clinical data were estimated by applying univariate and multivariate Cox-regression analyses. RESULTS: Among 208 patients with upper gastrointestinal contrast assessment, 87 cases were susceptible to radiochemotherapy treatment and the TGF-ß1-509CC, CT and TT genotype patients were 17 (19.5%), 48 (55.2%) and 22 (25.3%), respectively. Among the patients who were insensitive to radiochemotherapy treatment (n = 121), the TGF-ß1-509CC, CT and TT genotype patients were 39 (32.2%), 54 (44.6%) and 28 (23.2%), respectively. Compared with TGF-ß1-509CC genotype, the CT and TT genotype carriers had a significantly better treatment response (adjusted OR = 2.07, 95%CI, 1.05 - 4.09, P = 0.036). The median survival time of CC genotype patients was 17.0 (95%CI, 12.0 - 23.0) months, CT genotype patients was 22.0 (95%CI, 16.0 - 33.0) months and TT genotype patients was 25.0 (95%CI, 15.0 - 41.0) months. Compared to CC genotype patients, the survival time difference of CT and TT group was close to the statistical break point (P = 0.063). Our data showed that the subjects with CT or TT genotype had an decreased HR respectively as compared with those with CC genotype (CT, adjusted HR = 0.81, 95%CI, 0.52 - 1.24; TT, adjusted HR = 0.86, 95%CI, 0.65 - 1.12), but the difference was not statistically significant (P > 0.05). However, tumor location, clinical stage and radiochemotherapy response affected the overall survival time of the patient significantly (adjusted HR = 1.28, 95%CI: 1.01 - 1.61, P = 0.040; 1.49, 95%CI, 1.17 - 1.88, P = 0.001; 1.55, 95%CI, 1.06 - 2.26, P = 0.023, respectively). CONCLUSION: These results suggest that TGF-ß1-509C/T polymorphisms were associated with radiochemotherapy for esophageal squamous cell carcinoma which might be genetic markers for prediction of the radiochemotherapy response in ESCC patients.

[Clinical analysis of 126 patients with primary small cell carcinoma of the esophagus].

OBJECTIVE: To investigate the prognostic factors and the principles of treatment of primary esophageal small cell carcinoma (SCEC) retrospectively. METHODS: The data of 126 patients with histologically confirmed SCEC treated in our department between May 1985 and June 2005 were retrospectively analyzed. 85 patients were in limited disease stage (LD) and 41 patients as extensive disease stage (ED) according to the Veterans Administration Lung Study Group staging system. Among the 84 patients treated with esophagectomy, 8 cases were in stage I, 16 in stage IIa, 10 in stage IIb, 40 in stage III, 4 in stage IVa and 6 in stage IVb, according to the TNM system (6(th) edition, AJCC). Cox's hazard regression model was used to identify the prognostic factors, and Chi-square test to detect the difference of frequencies among different groups. Kaplan-Meier and log-rank methods were used to estimate and compare the survival rates. RESULTS: The median follow-up duration of this series was 13 months. One hundred and eight patients died of the disease during the follow-up, 10 were still alive and 8 were lost to follow-up. The 1-, 3-, and 5-year overall survival rates (OS) were 52.2%, 15.9%, and 12.2%, respectively, with a median survival time (MST) of 12.5 months. The 1-, 2-, and 3-year OS were 62.1%, 30.8%, and 22.4% with a MST of 14.0 months for LD, and 29.3%, 13.6% and 2.7% with a MST of 7.0 months for ED, respectively. There was a statistically significant difference in OS between LD and ED (P = 0.0001). The MST of the patients treated with chemotherapy was 14.5 months, significantly longer than the 5.2 months of the patients without (P = 0.0001). Multivariate analysis showed that stage (HR 1.91, 95% CI 1.26 approximately 2.91, P = 0.002), length of the primary lesion (HR 1.75, 95% CI 1.17 approximately 2.63, P = 0.007), and chemotherapy (HR 0.42, 95% CI 0.28 approximately 0.65, P = 0.000) were independent prognostic factors. CONCLUSION: Esophageal small cell carcinoma is a systemic disease. The tumor stage (LD or ED), length of the primary lesion and chemotherapy are independent prognostic factors. Therefore, a systemic therapy based on chemotherapy should be recommended.

[Postoperative three-dimensional conformal radiotherapy for resected non-small cell lung cancer].

OBJECTIVE: To investigate the association between survival and postoperative three-dimensional conformal radiotherapy (3DCRT) in patients with resected non-small cell lung cancer (NSCLC). METHODS: Eighty-four patients were treated with surgery and postoperative 3DCRT for NSCLC. Sixty-five (77.4%) patients received lobectomy, and 19 (22.6%) received pneumonectomy. Fifty-four (64.3%) patients achieved R0 resection and 30 cases (35.8%) received R1/R2 resection. Fifty-two patients were of stage IIIA and 24 patients were of stage IIIB. Photon energy of 6 MV was used for all the patients. The median 3DCRT dose was 60 Gy (40 - 70 Gy) with a fraction size of 2 Gy. Thirty-seven patients received median 3 cycles of adjuvant chemotherapy. The median follow-up was 35.5 months for survivors. RESULTS: The overall 3-year survival rate was 58.6%, and the 4-year overall survival rate was 43.9%. Of the 43 patients who had treatment failure, only 8 (9.9%) patients showed intrathoracic recurrence, but 38 (46.9%) patients had distant metastasis. The univariate analysis for all patients showed that sex, age, weight loss, tumor size, pathology and stage were not correlated with prognosis. R1/R2 resection was associated with a significantly worse survival. Toxicities were acceptable, with 9 (11.1%) patients appeared higher than NCI CTC grade 2 radiation pneumonitis. CONCLUSION: In a population-based cohort, postoperative 3DCRT for NSCLC provides a good prognosis, and the radiation-related pneumonitis is acceptable.

[Prognosis of locally advanced non small cell lung cancer treated with three dimentional conformal radiotherapy].

OBJECTIVE: To summarize our experience and evaluate the prognostic factors of locally advanced non small cell lung cancer (LA-NSCLC) treated with three dimentional conformal radiotherapy (3D-CRT). METHODS: 118 patients with stage IIImA/IIIB non small cell lung cancer were treated with 3D-CRT from Nov. 2001 to Mar. 2005. 113 patients with complete clinical data were eligible for analysis, 45 of them received radiotherapy alone; 39 were treated by concurrent chemoradiation with paclitaxol plus carboplatin in 32 patients and topotecan in 7 patients, and 29 by sequential chemoradiation with platinum-based regiment in most of them. The dose of radiation for the thoracic field ranged from 26 Gy to 75 Gy with a median dose of 60 Gy. GTV and PTV were collected from the 3D treatment plans in 79 and 101 patients, respectively. Overall survival (OS) was calculated using the Kaplan-Meier method. Comparisons among the curves were made using a two-tailed long-rank test. The Cox model was used for multivariate analysis. RESULTS: The 1-, 2- and 3-year overall survival rate was 60.7%, 31.6% and 22.4%, respectively, with a median survival time of 17 months. In univariate analysis, the following characteristics were significantly associated with longer survival: absence of chest pain, good karnofsky performance status (KPS), albumin > 4.2 g/L, hemoglobin > or = 140 g/L (male) or 130 g/L (female), response to radiotherapy and GTV < 100 cm3. However, multivariate analysis revealed that only good KPS was an independent risk factor predicting the survival. CONCLUSION: Three-dimensional conformal radiotherapy is effective in the treatment of locally advanced non-small cell lung cancer with acceptable complications. Karnofsky performance status is the only independent prognositic factor.

[Three-dimensional conformal radiotherapy for locoregionally recurrent non-small cell lung cancer after initial radiotherapy].

OBJECTIVE: To evaluate the feasibility, therapeutic effects and normal tissue complications of three-dimensional conformal radiotherapy (3DCRT) for locoregionally recurrent non-small cell lung cancer after initial radiotherapy. METHODS: Between August 1999 and August 2003, 27 such patients were treated with 3DCRT after initial radiotherapy. This series consisted of 25 men and 2 women with a median age of 64 years. Radiotherapy was delivered at 2 Gy per fraction, 5 fractions per week, to a median dose of 50 Gy. Treatment results and normal tissue complications were assessed with WHO and RTOG/EORTC criteria. RESULTS: Based upon a median follow-up time of 20.6 months, 25 patients (92.6%) completed the planned 3DCRT treatment. Their clinical symptom relief rate was 79.1%, and the response rate was 59.3% with a complete remission rate of 14.8% (4/27), partial remission rate of 44.4% (12/27). The overall 1- and 2-year survival (OS) rates were 73.8% and 25.4% with a median survival time (MST) of 20 months. The 1- and 2-year local progression free survival (LPFS) rates were both 88.8%. Grade 2 and grade 3 acute radiation pneumonitis developed in 7.4% (2/27) and 11.1% (3/27). Grade 2 late radiation pneumonitis developed in 11.1% (3/27). CONCLUSION: 3DCRT is feasible and advisable for locoregionally recurrent non-small-cell lung cancer, giving a good immediate tumor response and acceptable normal tissue complications.

Influence of number of metastatic lymph nodes on survival of curative resected thoracic esophageal cancer patients and value of radiotherapy: report of 549 cases.

PURPOSE: To analyze the significance of the number of metastatic lymph nodes on survival with and without the addition of prophylactic postoperative radiotherapy (RT) after radical resection of thoracic esophageal carcinoma. METHODS AND MATERIALS: A total of 549 thoracic esophageal squamous cell cancer patients who had undergone radical resection were randomized by the envelope method into a surgery-alone group (S, n = 275) and a surgery plus RT group (S+R, n = 274). We performed a retrospective review of all patients according to the extent of metastasis. The patients were classified into three groups: Group 1, 269 patients (49.0%) without lymph node involvement; Group 2, 159 patients (29.0%) with one to two positive nodes; and Group 3, 121 patients (22.0%) with three or more positive lymph nodes. RESULTS: For the same T stage (T3), the 5-year survival rate for Groups 1, 2, and 3 was 50.6%, 29.3%, and 11.7%, respectively (p = 0.0000). For patients with Stage III, the 5-year survival rate for Groups 1 (T4N0M0), 2 (T3-T4N1M0), and 3 (T3-T4N2M0) was 58.1%, 30.6%, and 14.4%, respectively (p = 0.0092). The 5-year survival rate of the S and S+R groups with positive lymph nodes (Groups 2 and 3) was 17.6% and 34.1% (p = 0.0378). In the positive lymph node groups, the incidence of failure by intrathoracic lymph node metastasis and supraclavicular lymph node metastasis in the S+R group (21.5% and 4.6%, respectively) was lower than in the S group (35.9% and 19.7%, respectively; p <0.012). In the negative lymph node group, the incidence of failure by intrathoracic lymph node metastasis in the S and S+R groups was 27.8% and 13.3%, respectively (p = 0.006). Hematogenous metastasis was the greatest (27.5%) in Group 3 (three or more positive lymph nodes). CONCLUSION: The number of metastatic lymph nodes is one of the important factors affecting the survival of patients with thoracic esophageal carcinoma. In our study, postoperative RT improved the survival of patients with positive lymph nodes. Additionally, postoperative RT reduced the incidence of intrathoracic recurrence and supraclavicular lymph node metastasis for all patients.

Patterns and predictors of recurrence after radical resection of thymoma.

BACKGROUND: Recurrence of thymomas even after complete resection is common, but the relapse patterns remain controversial. This study aimed to define the patterns and predictors of relapse after complete resection of thymoma. METHODS: A single-institution retrospective study was performed with 331 patients who underwent radical resection of thymoma between 1991 and 2012. RESULTS: After a median follow-up of 59 months, the recurrence rate was 6.9% (23/331). Relapse occurred in 23 patients with the pleura (14) and tumor bed (6) as the most common sites of recurrence. According to the definitions of the International Thymic Malignancy Interest Group, 10 (43.5%) patients had local relapse, 15 (65.2%) had regional relapse, 10 (43.5%) had distant relapse. The difference in survival following relapse between lung and regional relapse was statistically significant (P=0.027) but that between lung and distant relapse was not (P=0.808). The recurrence rates correlated with the initial Masaoka stage. Further, recurrence also correlated with World Health Organization (WHO) tumor type. The recurrence-free survival rates in patients with tumor size ⩾8 cm were worse than those of patients with tumor size <8 cm (P=0.007). Tumor size was also correlated with stage (r=0.110). As tumor becomes larger, the stage is more advanced (P=0.023). Multivariate analysis showed that Masaoka stage (P=0.005), tumor size (P=0.033), and WHO histological type (P=0.046) were predictive factors of relapse. CONCLUSION: Regional recurrence is the most common relapse pattern but local and distant relapse are also common. Advanced Masaoka stage, larger tumor size, and type B3 are risk factors of recurrence. Lung relapse should be considered distant relapse. Further, tumor size was correlated with Masaoka stage and therefore should be considered in the staging system.

Value of radiotherapy after radical surgery for esophageal carcinoma: a report of 495 patients.

BACKGROUND: Despite three decades of debate, no conclusion has been reached concerning the effectiveness of postoperative radiotherapy for resected esophageal carcinoma. From 1986 through 1997, a prospective randomized study was carried out with 495 patients in an attempt to define the value of this therapeutic modality. METHODS: A total of 495 patients with esophageal cancer who had undergone radical resection were randomized by the envelope method into a surgery-alone group (S) of 275 patients and a surgery plus radiotherapy group (S + R) of 220 patients. Radiation treatment was started 3 to 4 weeks after the operation. The portals encompassed the entire mediastinum and bilateral supraclavicular areas. A midplane dose of 50 to 60 Gy in 25 to 30 fractions was delivered over 5 to 6 weeks. RESULTS: The overall 5-year survival rate was 31.7% for the S group and 41.3% (p = 0.4474) for the S + R group. The 5-year survival rates of patients who were lymph node positive were 14.7% and 29.2% (p = 0.0698), respectively. Five-year survival rates of stage III patients were 13.1% and 35.1% (p = 0.0027), respectively. CONCLUSIONS: Postoperative prophylactic radiotherapy improved the 5-year survival rate in esophageal cancer patients with positive lymph node metastases and in patients with stage III disease compared with similar patients who did not receive radiation therapy. These results were almost significant for patients with positive lymph node metastases and highly significant for patients with stage III disease.

[Influence of the number of lymph node metastasis on survival and significance of postoperative radiotherapy for esophageal carcinoma].

OBJECTIVE: To analyze the influence of the number of lymph node metastasis on survival and prophylactic postoperative radiotherapy after radical resection of thoracic esophageal carcinoma. METHODS: Four hundred and ninety-five patients with thoracic esophageal squamous cell cancer who had undergone radical resection were randomly divided into surgery group alone (S, 275) and surgery plus radiotherapy group (S + R, 220). The patients were classified into three groups: Group A: 234 patients (47.2%) without lymph node involvement; Group B: 146 patients (29.5%) with 1 to 2 involved lymph nodes and Group C: 115 patients (23.2%) with >or= 3 involved lymph nodes. RESULTS: 1. The 5-year survival rate in Groups A, B and C for the same T stage (T3) was 52.6%, 28.8% and 10.9%, respectively (P = 0.0000); the 5-year survival rate in group C was 0% in S group and 19.3% in S + R group (P = 0.0336); 2. In the positive lymph node group, the metastatic rate of intra-thoracic and supraclavicular lymph node was 35.9% and 21.2% in S group and 19.7% and 4.4% in S+R group (P = 0.014 and P = 0.000). In the negative lymph node group, the metastatic rates of intra-thoracic lymph node was 27.8% in S group and 10.3% in S + R group (P = 0.003). The metastatic rate of intra-abdominal lymph node in Groups A, B and C was 3.9%, 9.4% and 17.5%, respectively (P = 0.0000). The occurrence of hematogenous metastasis was most frequent in group C (27.8%) with >or= 3 positive lymph nodes. CONCLUSION: 1. The number of metastatic lymph node is one of the important factors which affects the survival of thoracic esophageal carcinoma. 2. Chemotherapy might be given to the patients with three or more lymph nodes involved who have the possibility of developing hematogenous metastasis. Postoperative radiotherapy can reduce the occurrence of intra-thoracic and supraclavicular lymph node metastasis and improve the survival of patients with three or more lymph nodes involvement.

Role of adjuvant radiotherapy for stage II thymoma after complete tumor resection.

PURPOSE: To determine whether patients with Masaoka stage II thymoma benefit from adjuvant radiation therapy after complete tumor resection. METHODS AND MATERIALS: A total of 107 patients with stage II thymoma who underwent complete resection of their tumors between September 1964 and October 2006 were retrospectively analyzed. Sixty-six patients were treated with adjuvant radiotherapy, and 41 patients received surgery alone. RESULTS: Eight patients (7.5%) had a relapse of their disease, including two patients (4.5%) who had surgery alone, and 6 patients (9.5%) who had adjuvant radiation therapy. Disease-free survival rates at 5 and 10 years were 92.3% and 82.6%, respectively, for the surgery-plus-radiation group, and 97.6% and 93.1%, respectively, for the group that underwent surgery alone (p = 0.265). Disease-specific survival rates at 5 and 10 years were 96.4% and 89.3%, respectively, for the surgery-plus-radiation group and 97.5% and 97.5% for the surgery group (p = 0.973). On univariate analysis, patients with type B3 thymomas had the lowest disease-free survival rates among all subtypes (p = 0.001), and patients with large thymomas (>7 cm) had lower disease-specific survival rates than those with small tumors (<7 cm) (p = 0.017). On multivariate analysis, histological type (type B3) thymoma was a significant independent prognostic factor. CONCLUSIONS: Adjuvant radiotherapy after complete tumor resection for patients with stage II thymoma did not significantly reduce recurrence rates or improve survival rates. Histological type (type B3) thymoma was a significant independent prognostic factor. Further investigation should be carried out using a multicenter randomized or controlled study.