Adjuvant treatment in patients at high risk of recurrence of thymoma: efficacy and safety of a three-dimensional conformal radiation therapy regimen

Diagnostic value of apparent diffusion coefficient in predicting pathological T stage in patients with thymic epithelial tumor

Purposes

This study aimed to evaluate the diagnostic capacity of apparent diffusion coefficient (ADC) in predicting pathological Masaoka and T stages in patients with thymic epithelial tumors (TETs).

Methods

Medical records of 62 patients who were diagnosed with TET and underwent diffusion-weighted imaging (DWI) prior to surgery between August 2017 and July 2021 were retrospectively analyzed. ADC values were calculated from DWI images using b values of 0, 400, and 800 s/mm². Pathological stages were determined by histological examination of surgical specimens. Cut-off points of ADC values were calculated via receiver operating characteristic (ROC) analysis.

Results

Patients had a mean age of 56.3 years. Mean ADC values were negatively correlated with pathological Masaoka and T stages. Higher values of the area under the ROC curve suggested that mean ADC values more accurately predicated pathological T stages than pathological Masaoka stages. The optimal cut-off points of mean ADC were 1.62, 1.31, and 1.48 × 10^–3 mm²/sec for distinguishing pathological T2-T4 from pathological T1, pathological T4 from pathological T1-T3, and pathological T3-T4 from pathological T2, respectively.

Conclusion

ADC seems to more precisely predict pathological T stages, compared to pathological Masaoka stage. The cut-off values of ADC identified may be used to preoperatively predict pathological T stages of TETs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40644-022-00495-x.

On the risk of secondary cancer from thymoma radiotherapy

Objective. This study aims at quantifying the lifetime attributable risk of secondary fatal cancer (LARFAC) to patients receiving adjuvant radiotherapy treatment for thymoma, a neoplasm where cure rates and life expectancy are relatively high, patient age at presentation relatively low and indications for radiotherapy controversial depending on the disease stage. Approach. An anthropomorphic phantom was scanned, organs were contoured and a standard 6 MV 3DCRT treatment plan was produced for thymoma treatment. The phantom was loaded with thermoluminescent dosimeters (TLDs) and treated by linear accelerator per plan. The TLDs were subsequently read for out-of-field dose distribution while in-field dose distribution was obtained from the planning system. Sex and age-specific lifetime radiogenic cancer risk was calculated as the sum of in-field risk and out-of-field risk. The latter risk was estimated using hybrid ICRP 2007 103-BEIR VII tables of organ-specific risks based on the linear-no threshold (LNT) model and applicable at low doses, while the former using mathematical risk models applicable at high doses. Main results. The LARFAC associated with a prescribed dose of 50 Gy to target volume in 25 fractions was in the approximate range of 1%–3%. The risk was higher for young and female patients. The largest contributing organ to this risk were the lungs by far. Using the LNT model inappropriately to calculate risk at therapeutic doses (in-field) would overestimate the risk up to tenfold. Significance. The LARFAC to patient from thymoma radiotherapy was quantified taking into consideration the inapplicability of the LNT model at therapeutic doses. The risk is not negligible; the information may be relevant to patients and clinicians.

Proton therapy for thymic malignancies: multi-institutional patterns-of-care and early clinical outcomes from the proton collaborative group and the university of Florida prospective registries

Objective: Thymic malignancies (TM) are rare tumors with long-term survivorship, causing concerns for radiotherapy-related late side effects. Proton therapy (PT) reduces the radiation dose to organs at risk, potentially decreasing long-term toxicities while preserving disease control. We report patterns-of-care and early clinical outcomes after PT for thymoma and thymic carcinoma. Methods: Between January 2008 and March 2017, 30 patients with TMs enrolled on one of two IRB-approved prospective protocols and received postoperative or definitive PT. Clinical outcomes, pathology, treatment dose, toxicities, and follow-up information were analyzed. Results: Twenty-two thymoma patients with a median age of 52.1 years (range, 23-72) received a median RT dose of 54 Gy (RBE) (range, 45-70) either postoperatively (91%) or definitively (9%); 23% received adjuvant chemotherapy. Among eight thymic carcinoma patients, the median age was 65.5 years (range, 38-88) and median RT dose was 60 Gy (RBE) (range, 42-70) delivered postoperatively (75%) or definitively (25%); 50% received chemotherapy. Median follow-up for all patients was 13 months (range, 2-59 months). Five patients relapsed, one locally (3%). Three patients died of disease progression, including two thymomas and one thymic carcinoma patient; a fourth died of intercurrent disease. One patient with thymic carcinoma and 1 with thymoma are alive with disease. No patients treated with PT for their initial disease (de novo) experienced grade ≥3 toxicities. The most common grade 2 toxicities were dermatitis (37%), cough (13%), and esophagitis (10%). Conclusion: Adjuvant and definitive PT are being used in the treatment of TMs. Early results of the largest such cohort reported to date demonstrates an acceptable rate of recurrence with a favorable toxicity profile. Longer follow-up and a larger patient cohort are needed to confirm these findings.

Concurrent preoperative chemotherapy and three-dimensional conformal radiotherapy followed by surgery for oral squamous cell carcinoma: a retrospective analysis of 104 cases

Objectives

The objectives of this study were to assess the clinical effects of an integrated program consisting of concurrent preoperative combined paclitaxel and nedaplatin chemotherapy and three-dimensional conformal radiotherapy followed by surgery intended to cure oral squamous cell carcinoma and to determine whether this integrated program is feasible and effective with respect to the treatment of oral squamous cell carcinoma.

Methods

A total of 104 biopsy-confirmed patients who presented with oral squamous cell carcinoma for the first time were included in this study. Concurrent preoperative combined paclitaxel and nedaplatin chemotherapy and three-dimensional conformal radiotherapy were administered to these patients. The most common treatment regimen consisted of infusions of paclitaxel (135-175 mg/m²/day), infusions of nedaplatin (150 mg; 80-100 mg/m²/day), and irradiation at doses ranging from 1.5 Gy twice daily to 30-40 Gy over 3-4 weeks. The clinical variables evaluated herein included the local recurrence rate, distant metastasis rate, postoperative survival rate, and degree of mouth opening restriction.

Results

The median follow-up time for surviving patients was 60 months, and the median time to progression for all patients was 57.69 months (95% confidence interval, 56.09 to 59.29 months, and the 3-year disease-free survival probability was 97.11%). The effectiveness rate of the integrated program was 98.08%, and the surgery resection rate was 100%. Only a few postoperative adverse reactions were observed. The local recurrence and distant metastasis rates were 1.92% (2 patients) and 2.88% (3 patients), respectively. The titanium rejection and infection reaction rate that led to restriction of mouth opening was only 2.88% (3 patients). Finally, the 5-year post-surgery survival rate was 91.35% (95 patients).

Conclusion

Preoperative combined paclitaxel and nedaplatin chemotherapy and three-dimensional conformal radiotherapy have significant clinical effects leading to positive anti-tumor results in patients with oral squamous cell carcinoma. These treatments also increase the likelihood that patients will undergo successful surgical treatment. The integrated program described herein can increase long-term survival and surgery resection rates and is associated with only a limited number of adverse reactions.