Study design and patients
This single-center, retrospective study included data from 17 patients who were diagnosed with and treated for PTL at our institution between January 2012 and December 2022. The patient cohort consisted of 2 males and 15 females, aged 34–88 years (mean 66.3 ± 20.7, median 67 years; Table 1). All patients possessed comprehensive medical records and underwent standardized chemotherapy. Grey-scale and color Doppler ultrasound (CDU) were employed pre- and post-treatment. Additionally, one patient underwent contrast-enhanced ultrasound (CEUS) examination. Exclusion criteria encompassed pregnant or lactating women, and patients with contraindications to chemotherapy, or a projected survival time of <2 months. The study received approval from the ethics committee of the authors’ Hospital (Ethical project number: LM2023557; 2023-09-07) and written informed consent was obtained from each patient before any biopsy or chemotherapy procedures.
Sonographic examinations
Ultrasound examinations were conducted using a GE LOGIQ E9 (GE Healthcare, Wauwatosa, WI, USA), an HI VISION Avius L (Hitachi High-Tech Co., Tokyo, Japan), and a Samsung RS80A (Samsung Medison Co. Ltd., Seoul, Korea) fitted with a high-frequency linear array probe. A low-frequency convex array probe was employed for larger masses. Thyroid and cervical lymph nodes were scanned in transverse, longitudinal, and multiple oblique planes. Clinical parameters and sonographic data were retrieved from electronic medical records, and reviewed by two authors, each with >5 years of corresponding experience. Recorded data included the thyroid size, background echotexture, and ultrasonic characteristics. Sonography appearances of PTL were categorized into three types: diffuse, nodular, and mixed [5]. Lesions were measured in three axes for nodular types, and the volume (V) was calculated using the formula V = 0.52abc, where a, b, and c represent the length, width, and thickness diameter of the nodule, respectively. Thyroid gland thickness was measured for diffuse and mixed types. Internal blood flow supply was graded into four categories using the Adler semi-quantitative method [6].
Treatment protocol, efficacy evaluation, and follow-up
All patients underwent chemotherapy, receiving R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) or a CHOP-like regimen. The exception was one case of mucosa-associated lymphatic tissue lymphoma, which received the R-CVP regimen (rituximab combined with cyclophosphamide, vincristine, and prednisone). The course of all treatments spanned 2–3 weeks. If the lesion persisted after four treatment courses, a recommendation was made to alter the chemotherapy. Grey-scale and CDU were performed simultaneously after 2 and 4 cycles of chemotherapy, and assessments were completed upon concluding the entire treatment. The treatment response was evaluated using the Lugano 2014 evaluation criteria [7], categorizing outcomes into four types: complete remission (CR), partial remission (PR), stable disease (SD), and disease progression (PD). CR and PR were considered an overall response (OR), while SD and PD were considered no response (NR). A PET-CT scan was conducted 6–8 weeks after completing the entire treatment. Follow-up included outpatient visits and telephone communication up to December 31, 2022, or the time of death. Progression-free survival (PFS) was defined as the time from initial therapy to tumor progression (local tumor progression or lesions involving other organs) or patient death. Overall survival (OS) was measured from the time of initial therapy to patient death from any cause or last contact.
Statistical Analyses
Data analysis was performed using SPSS (Version 17.0; IBM, Armonk, NY, USA). Baseline data were presented for quantitative variables as mean ± standard deviation and qualitative variables as percentages. Mean quantitative values were compared using the Student’s t-test and nonparametric data were assessed using the Mann–Whitney U test. Proportional differences were analyzed through the chi-square test. The Kaplan–Meier method estimated PFS and OS, and the log-rank test was used to compare differences. A p-value <0.05 was considered statistically significant.