Rico M, Flamarique S, Casares C, García T, López M, Martínez M, Serrano J, Blanco M, Hernanz R, de Ingunza-Barón L, Marcos FJ, Couñago F. GOECP/SEOR radiotherapy guidelines for thymic epithelial tumours. World J Clin Oncol 2021; 12(4): 195-216 [PMID: 33959475 DOI: 10.5306/wjco.v12.i4.195]
Corresponding Author of This Article
Mikel Rico, MD, PhD, Doctor, Department of Radiation Oncology, Complejo Hospitalario de Navarra, C/Irunlarrea 3, Pamplona 31008, Navarra, Spain. mikel.rico.oses@navarra.es
Research Domain of This Article
Oncology
Article-Type of This Article
Guidelines
Open-Access Policy of This Article
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World J Clin Oncol. Apr 24, 2021; 12(4): 195-216 Published online Apr 24, 2021. doi: 10.5306/wjco.v12.i4.195
Table 1 Levels of evidence and grades of recommendation
Levels of evidence
I
Evidence from at least one large RCT of good methodological quality (low potential for bias) or meta-analyses of well-conducted randomised trials without heterogeneity
II
Small or large RCTs with suspicion of bias (lower methodological quality) or meta-analyses of such trials with demonstrated heterogeneity
III
Prospective cohort studies
IV
Retrospective cohort studies or case-control studies
V
Studies without control group, case reports, expert opinions
Grades of recommendation
A
Strong evidence for efficacy with a substantial benefit, strongly recommended
B
Strong or moderate evidence for efficacy but with a limited clinical benefit, generally recommended
C
Insufficient evidence for efficacy or benefit does not outweigh the risk or the disadvantages (adverse events, costs, etc.), optional
D
Moderate evidence against efficacy or for adverse outcome, generally not recommended
E
Strong evidence against efficacy or for adverse outcome, never recommended
Table 2 Characteristic clinical manifestation of thymomas and differential diagnosis with other causes of mediastinal masses
Thymus-like architecture and cytology: Abundance of immature T cells, areas of medullary differentiation (medullary islands); paucity of polygonal or dendritic epithelia cells without clustering (i.e., < 3 contiguous epithelial cells)
Hassall’s corpuscles; perivascular spaces
Type B2
Increased numbers of single or clustered polygonal or dendritic epithelial cells intermingled with abundant immature T cells
Sheets of polygonal slightly to moderately atypical epithelial cells; absent or rare intercellular bridges; paucity or absence of intermingled TdT+ T cells
Hassall’s corpuscles; perivascular spaces
MNT
Nodules of bland spindle or oval epithelial cells surrounded by an epithelial cell-free lymphoid stroma lymphoid stroma
Lymphoid follicles; monoclonal B cells and/or plasma cells (rare)
Metaplasticthymoma
Biphasic tumor composed of solid areas of epithelial cells in a background of bland-looking spindle cells; absence of immature T cells
Pleomorphism of epithelial cells; actin, keratin, or EMA-positive spindle cells
Table 4 Clinical stage of thymic epithelial tumours according to Masaoka-Koga
Stage
Diagnostic criteria
10-yr survival
I
Tumours encapsulated macroscopically and microscopically (without capsular invasion)
84% (81%-86%)
II
A: Microscopic transcapsular invasion
83% (79%-87%)
B: Macroscopic invasion of fatty tissue or pleural and/or pericardial adhesion
III
Macroscopic involvement of adjacent structures (pericardium, great vessels, or lung). A: With invasion of great vessels
70% (64%-75%)
B: Without invasion of great vessels
IV
A: Pleural or pericardial spread
42% (26%-58%)
B: Hematogenous or lymphogenic metastasis
53% (32%-73%)
Table 5 Clinical stage of thymic epithelial tumours: International Association for the Study of Lung Cancer/International Thymic Malignancy Interest Group tumor-node-metastasis
Stage
Description
Primary tumor (T)
T1
T1a
Encapsulated or unencapsulated, with or without extension into mediastinal fat
T1b
Extension into mediastinal pleura
T2
Direct invasion of the pericardium (partial or full thickness)
T3
Direct invasion of the lung, brachiocephalic vein, superior vena cava, chest wall, phrenic nerveand/or hilar (extrapericardial) pulmonary vessels
T4
Direct invasion of the aorta, main pulmonary artery, myocardium, trachea, or esophagus
Lung (total lung minus GTV; solely total lung for postoperative cases without GTV)
Mean dose < 20 Gy
Mean dose < 8 Gy if post-pneumonectomy
RT alone
RT with chemotherapy
Neoadjuvant treatment before surgery
V20 ≤ 40%
V20 ≤ 35%
V20 ≤ 30%
V10 ≤ 45%
V10 ≤ 40%
V5 ≤ 65%
V5 ≤ 55%
V20 < 10% and V5 < 60% if post-pneumonectomy
Heart
Mean dose < 26 Gy
V30 ≤ 45%
Esophagus
Mean dose < 34 Gy
Dmax ≤ 80 Gy
V70 < 20%
V50 < 50%
Kidney
20 Gy < 32% bilateral kidney
Liver
Mean dose < 30 Gy
V30 ≤ 40%
Citation: Rico M, Flamarique S, Casares C, García T, López M, Martínez M, Serrano J, Blanco M, Hernanz R, de Ingunza-Barón L, Marcos FJ, Couñago F. GOECP/SEOR radiotherapy guidelines for thymic epithelial tumours. World J Clin Oncol 2021; 12(4): 195-216