thyroid cancer and breast cancer
Conditions
Interventions
Second primary tumor group:None
No second tumor group:None
SEER cohort:None
Sponsors
Sun Yat-sen Memorial Hospital, Sun Yat-sen University
Eligibility
Sex/Gender
Female
Age
18 Years to No maximum
Inclusion criteria
Inclusion criteria: Real-world cohort: 1. Age >= 18 years, female gender 2. Pathologically confirmed thyroid cancer or breast cancer (index cancer) 3. Second primary malignancy (i.e., the other cancer type: if index cancer is thyroid cancer, second primary is breast cancer; if index cancer is breast cancer, second primary is thyroid cancer) pathologically diagnosed during follow-up after index cancer diagnosis 4. Both tumors meet the definition of second primary cancer: based on Warren & Gates criteria (1932) and SEER "Multiple Primary Rules", i.e., different histological types (e.g., papillary carcinoma vs. invasive ductal carcinoma), or same type but anatomically separated and non-metastatic; one tumor excluded as a metastasis of the other 5. Relatively complete clinical data, including basic demographic information, tumor staging, treatment records, and follow-up outcomes SEER cohort: 1. Female gender 2. Registered with two independent primary malignancies during follow-up: thyroid cancer (ICD-O-3: C73.9) and breast cancer (ICD-O-3: C50.0–C50.9) 3. Complies with SEER official "Multiple Primary Cancer" determination rules (automatically identified based on ICD-O-3 histology code and site combination), ensuring both cancers are primary sites 4. Index cancer diagnosis year between 2000–2021, and second primary cancer occurred after index cancer diagnosis 5. Available survival time, cause of death, and basic demographic and tumor characteristic data
Exclusion criteria
Exclusion criteria: Real-world cohort: 1. Distant metastasis (M1 stage) present at diagnosis 2. Second tumor is a benign lesion, carcinoma in situ (e.g., DCIS, thyroid micro-papillary carcinoma not meeting invasive criteria), or metastatic cancer 3. Missing rate of key variables >30% (e.g., no pathological type, no follow-up records) 4. Concurrent third primary malignancy other than thyroid cancer and breast cancer (to avoid confounding) SEER cohort: 1. Either tumor marked as "autopsy only" or "diagnosis source unreliable" 2. Missing key covariates (e.g., age, race, stage, histological type) that cannot be reasonably imputed via SEER derived variables 3. Second primary cancer occurred before index cancer diagnosis (logical error) 4. Data from non-population-based registry sub-collections (e.g., subset limited to specific hospitals) to ensure representativeness
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Occurrence of second primary cancer (pathologically confirmed and meeting Warren & Gates criteria or SEER Multiple Primary Rules for another primary malignancy); | — |
Secondary
| Measure | Time frame |
|---|---|
| Demographic characteristics (age, sex, race, marital status, income level, residential area size);Clinicopathological characteristics (primary cancer type, AJCC 8th edition staging, histological subtype, immunohistochemistry, tumor status, endocrine status, lymph node metastasis status, hormone levels, hormone receptor status ER/PR/HER2, BRAF/RAS mutation status, treatment modality);Disease-Free Survival (DFS);Overall Survival (OS);Model discrimination (Area Under the Curve, AUC);Model calibration;Clinical utility of model (Decision Curve Analysis); | — |
Countries
China
Contacts
Public ContactChen Huaxian
Sun Yat-sen Memorial Hospital, Sun Yat-sen University
Outcome results
None listed