[胸腺腫瘤] 胸腺腫瘤治療介紹

胸腺瘤是長在胸腺的腫瘤, 不算常見, 不過臨床上還是有機會遇到, 以下來做個介紹! 主要是參考NCCN 的資料! 胸腺腫瘤主要分成兩大類, 分別是胸腺瘤(thymoma), 或是胸腺癌(thymic carcinoma), 90% 的胸腺腫瘤都是thymoma

1.  initial presentation: 

咳嗽, 喘, 胸痛之類的症狀 => 去醫院檢查 => CxR => mediastinum mass

45% 的 thymoma 病人會合併重症肌無力(Myasthenia gravis)

2.  initial survey:

(1) Chest CT with contrast, serum beta HCG, AFP

(2) 初始survey後, 臨床上看是否像是胸腺腫瘤, 如果是的話就考慮開刀(total thymectomy + complete excision of tumor), 不像的話就做切片

3. 分期: 有兩種分期, 分別是Modified Masaoka stage 跟 AJCC stage

(1) Modified Masaoka stage

Stage 1: Macroscopically and microscopically encapsulated 

Stage 2: 

       (A) Microscopically transcapsular invasion

       (B) Macroscopic invasion into thymic or surrounding fatty tissue, or grossly adherent to but not  breaking through mediastinal pleura or pericardium

Stage 3: Macroscopic invasion into neighboring organ (i.e., pericardium, great vessel, or lung)

       (A) without vascular invasion

       (B) with vascular invasion

Stage 4:

       (A) Pleural or pericardial metastases

       (B) Lymphogenous or hematogenous metastasis

(2) AJCC stage 

4. 病理型態(WHO 分型): 

Type A    : neoplastic oval or spindle-shaped epithelial cells without atypia or lymphocytes

Type AB : neoplastic oval or spindle-shaped epithelial cells with foci of lymphocytes

Type B    : plump epithelioid cells, 可再分為B1, B2, B3

Type B1  : resemble normal thymic cortex with areas similar to thymic medulla

Type B2  : scattered neoplastic epithelial cells with vesicular nuclei and distinct nucleoli among a heavy population of lymphocytes

Type B3  : predominantly round or polygonal epithelial cells exhibiting mild atypia admixed with a minor component of lymphocytes

Type C   :  thymic carcinoma

5. 術後處置(依照手術邊緣是否乾淨,決定後續治療):

(1) R0 resection:

Thymoma or Thymic carcinoma, Masaoka stage I -> surveilence

Thymoma or Thymic carcinoma, Masaoka stage II-IV -> consider adjuvant RT

(2) R1 resection:

Thymoma: adjuvant RT

Thymic carcinoma: adjuvant RT +/- CT

(3) R2 resection:  

Thymoma: definitive RT +/- CT

Thymic carcinoma: definitive RT + CT

reference:

1.  NCCN guideline

2.  Perez and Brady's radiation oncology