Prognostic evaluation models for primary thyroid lymphoma, based on the SEER database and an external validation cohort

Abstract

Purpose Primary thyroid lymphoma (PTL) is a rare malignancy, and the literature is limited to small case series and case reports. This study aimed to assess the epidemiologic characteristics, survival, and prognostic factors of patients with PTL. Methods We analyzed 2215 PTL patients from the Surveillance, Epidemiology, and End Results database medical records, between 1983 and 2015, as the training cohort. We enrolled 105 patients from the Cancer Hospital, Chinese Academy of Medical Sciences, for the external validation cohort. The nomograms for predicting the 1-, 5-, and 10-year overall survival (OS) and lymphoma-specific survival (LSS) were constructed. Results PTL incidence steadily increased from 1977 to 1994, with an annual percentage change of 3.2% (95% confidence interval [CI]: 1.2–5.2, P < 0.05). The 1-, 5-, and 10-year OS and LSS rates were 84.66%, 71.61%, and 55.95%; and 90.5%, 85.7%, and 82.2%, respectively. Multivariate Cox regression analysis revealed that shorter OS association with age ≥ 60 years (hazard ratio [HR], 3.94; 95% CI 3.31–4.69; P < 0.001), unmarried status (HR, 1.55; 95% CI 1.37–1.75; P < 0.001), Ann Arbor stage III-IV (HR, 1.55; 95% CI 1.37–1.75; P = 0.020), diffuse large B-cell lymphoma (HR, 2.60; 95% CI 1.15–5.87; P = 0.022), and T cell non–Hodgkin lymphoma (HR, 3.53; 95% CI 1.12–11.10; P = 0.031). In the multivariate competing-risk analyzes, age, stages III-IV, year of diagnosis, surgery, radiation, chemotherapy, and histology were strongly predictive of PTL-specific risk of death. To estimate the 1-, 5-, and 10-year LSS and OS rates, respectively, nomograms were built. In the validation cohort, the results also confirmed the utility. Conclusions This study presents the first prognostic model with an external validation that could help clinicians identify patients with high-risk PTL to improve their prognosis.

Thyroid lymphoma

“…With regards to stage at diagnosis, at the end of last century, it was reported that almost 80% of patients have limited disease [32,33]. A more recent study in 2015 reported that 92.1% of patients had Ann Arbor stage I–II disease [34] similar to a more recent one in 2022 showing that 87.6% of new PTL cases were Ann Arbor stages I–II [2 ▪▪ ]. The very small percentage of more advanced stages could be explained by the lack of histological markers that allow differentiation between PTL and those lymphomas that are metastatic to the thyroid gland with the latter group more likely to be diagnosed as metastatic disease to the thyroid gland as opposed to PTL.…”

“…PTL is more common in female individuals and has a female-to-male ratio of 4–2.5 to 1 [2 ▪▪ ,3] with a mean age at diagnosis around 65 years of age [3]. PTL frequently occurs in patients with preexisting Hashimoto thyroiditis being this the only associated risk factor carrying almost 60 times higher risk in those with Hashimoto thyroiditis compared with those without [4].…”

“…For early stage MALTL and mixed type (MALTL, DLBCL) cases, a 5-year survival rate of 100% has been reported and 87.5% for DLCBL cases [36]. A study with 2215 PTL patients collected from Surveillance, Epidemiology, and End Results (SEER) database between 1983 and 2015 reported 1-year, 5-year, and 10-year overall survival rates of 84.66, 71.61, and 55.95%, respectively, and corresponding disease-specific survival rates of 90.5, 85.7, and 82.2%, respectively [2 ▪▪ ]. Vardell Noble et al [37] used the National Cancer Database and reported a 75% 5-year overall survival, which ranged from 66 to 74% in other studies [3,38].…”

“…The Ann Arbor staging system helps to predict outcomes for patients with lymphoma but does not consider some important risk factors such as patient characteristics and treatment modality [1 ▪▪ ]. Zhu et al [2 ▪▪ ] identified seven independent risk factors for overall survival, namely, age, histology, Ann Arbor stage, surgery, chemotherapy, radiation, and marital status, using the univariate and multivariate Cox analyses. Considering the influence of the risk factors, the conventional Ann Arbor staging system may not be a good predictor of disease-specific survival in patients with PTL either.…”

Development and validation of a nomogram to predict B-cell primary thyroid malignant lymphoma-specific survival: A population-based analysis

“…Study subject data were downloaded from the official website of the SEER database (https://seer.cancer.gov/, covering 18 registries including samples from 2000-2018) using SEER*Stat (Version 8.3.9.2, https://seer.cancer.gov/data-software/). Samples were included if they (1) were from 2000-2015 (because Ann Arbor staging was not updated after 2016) (2), had an ICD-O-3 (International Classification of Diseases for Oncology, Third Edition) code 9670 to 9699 or 9728 (7,8), (3) had a primary site code of 73.9 for thyroid gland, and (4) the sequence number indicates the only primary or first primary tumors. Samples were excluded if (1) the primary site surgery was unknown, (2) race of the patient was unknown, (3) survival month was 0 or unknown, or (4) Ann Arbor Stage was unknown (Figure 1).…”