[ROQs] Thoracic: Meso, Thymoma, Misc Flashcards
What is the TNM staging for malignant mesothelioma?
Note: Histopathology is more prognostic than TNM stage
What are the recommended RT doses for thymomas?
Thymoma RT dosing:
- Unresectable disease: ~60-70 Gy, respecting OARs.
- PORT:
– Clear or close surgical margins: 45-50 Gy
– +margins, microscopic disease: 54 Gy
– Gross residual disease: 60-70 Gy
What is the 5-yr freedom from failure for an unresectable thymic carcinoma or thymoma s/p induction CHT (PAC x2=4C) f/b 54 Gy mediastinal RT f/b consolidation CHT?
- Overall Response Rate: 70%
– Complete Response Rate: 22% - 5-yr FFF: 54%
- 5-yr OS: 53%
[INT Loehrer et al. JCO 1997]
What are the findings of the MARS2 trial for the treatment of resectable malignant mesothelioma?
The MARS2 trial, a phase 3 randomized controlled trial, compared extended pleurectomy decortication (EPD) and chemotherapy (cisplatin/carboplatin + pemetrexed) in patients with resectable malignant pleural mesothelioma (MPM). The main findings of the MARS2 trial are as follows:
- Overall Survival (OS): The median OS was shorter in the surgery and chemotherapy group (19.3 months) compared to the chemotherapy alone group (24.8 months). The difference in restricted mean survival time at 2 years was -1.9 months (95% CI -3.4 to -0.3, p=0.019).
- Serious Adverse Events: There were significantly more serious adverse events (Grade ≥3) in the surgery group (318 events) compared to the chemotherapy group (169 events). The incidence rate ratio was 3.6 (95% CI 2.3 to 5.5, p<0.0001), with increased incidences of cardiac and respiratory disorders, infections, and additional surgical or medical procedures in the surgery group.
- Interpretation: The trial concluded that extended pleurectomy decortication was associated with worse survival and more serious adverse events compared to chemotherapy alone. This finding suggests that EPD may not provide a survival benefit and could increase the risk of severe complications in patients with resectable MPM.
What is the Masaoka staging for thymomas?
- Stage I - macroscopically completely encapsulated and no microscopic capsular invasion
- Stage II
– Ila - microscopic invasion into capsule
– Ilb - macroscopic invasion into surrounding fatty tissue or grossly adherent to but not
breaking through the mediastinal pleura or pericardium - Stage IlI - macroscopic invasion into neighboring structures, i.e., mediastinum, pericardium,
great vessels, or lung as well as invasion into the mediastinal pleura - Stage IVa - pleural or pericardial implants
- Stage IVb - lymphatic or hematogenous metastasis
What are the approx DFS survival for thymomas stratified by Masaoka and WHO classifications?
- 10-yr DFS based on Masaoka staging:
– Stage I: 94%
– Stage II: 88%
– Stage III: 66% - 10-yr DFS based on WHO histologic classification:
– A: 95% [Bonus: 5-yr OS: 100%!]
– AB: 90%
– B1: 85%
– B2:71%
– B3: 40%
[Rena et al. Lung Cancer 2005]
What is the AJCC 8th ed. TNM staging for thymomas?
What is the most common route of spread for thymomas?
- Pleural or pericardial metastases
- Good long term survival can still be achieved w/ resection of the primary and any pleural or pericardial implants.
Which mesothelioma histologic subtypes have the best prognosis?
- Epithelioid → Only ones you should consider for surgical resection
What does extrapleural pneumonectomy remove?
- Extrapleural pneumonectomy involves removal of
– Parietal and visceral pleura
– Lung
– Hemi-diaphragm
– Ipsilateral half of pericardium - Perioperative mortality is 5-15%
- 2-yr OS: 30-40%
- Patients are not candidates if there is an extension through the diaphragm
- Pleurectomy-decortication (P/D) involves the removal of
– Parietal and visceral pleura
– Leaves lung, diaphragm, and pericardium intact (removed w/ extended P/D)
What is the long-term cure rate of extragonadal non-seminomatous germ cell (NSGC) tumor of the mediastinum?
- General treatment paradigm for extragonadal NSGCT:
– Typically treated w/ platinum-based CHT ± surgery
– 1/2 undergo surgery for residual mass resection - 5-yr PFS and OS for mediastinal NSGC: 44%, 45%
- 5-yr OS for retroperitoneal NSGC: 62%
- Contrast w/ cure rates for extra-gonadal SGCT: 90%!
- Mediastinal NSGCT are considered poor risk due to above criteria. Other poor risk characteristics include:
– S3: AFP > 10k, bHCG > 50k
– Non-pulmonary visceral mets
What is the long-term cure rate of extragonadal non-seminomatous germ cell (NSGC) tumor of the mediastinum?
- General treatment paradigm for extragonadal seminomas:
- Typically treated w/ platinum-based CHT f/b surgery for residual mass resection
- ORR si ~90%, w/ 66% achieving complete response
- 5-yr OS for extragonadal seminomas, regardless of location: 88%
[Bokemeyer et al JCO 2002]
What is the standard CHT for malignant pleural mesothelioma?
- Pemetrexed and Cisplatin
What is the tissue of origin for mesothelioma?
- Most commonly, pleura (80%)
- Other tissues: Peritoneum, pericardium, tunica vaginalis
What is the standard CHT for thymomas or thymic carcinomas?
- Thymoma: Cisplatin, doxorubicin, cyclophosphamide
- Thymic Carcinoma: Cyclophosphamide, adriamycin, cisplatin, prednisone (CAPP)
What are the broad strokes of the traditional hemothoracic RT for malignant pleural mesothelioma?
- Traditional/historic total PORT dose usign 3DC: 50.4 - 54 Gy
- In the current era, IMRT is used and there is a large variation in the doses used
What are the traditional borders of hemithoracic RT after EPP for malignant pleural mesothelioma?
Do you need a bx for thymomas?
Serum markers to r/o germ cell tumors will be -ve for thymomas.
When should RT be considered for thymomas?
What is the contralateral lung constraint for patients receiving IMRT RT for malignant pleural mesothelioma s/p EPP?
- Lung V20 < 7%
– >7% → 42 fold ↑ in pulmonary-related death
[Rice et al. IJROBP 2007]
What is the approx 3-yr OS for patients w/ malignant pleural mesothelioma confined to the pleural space?
- 3-yr Only 25%
- Aggressive disease w/ a high risk of progression and death even at lower stages
Is there any benefit to hemothoracic IMRT in patients w/ non-matastatic malignant pleural mesothelioma?
- Yes, per Trovo et al Italy IJROBP 2021
- Hemithoracic IMRT (50/25, if gross disease 60/25)
- Improves LRFS and OS, but NOT DMFS
How does the Masaoka staging compare to the AJCC 9th edition for thymomas and thymic carcinomas?
What is the general treatment paradigm for non-metastatic extragonadal seminomas?
- No firmly established tx guidelines, so tx may vary based on institution
- However, they respond really well to CHT (BEP x3C, or EP x4C)
- Surgery may be considered for residual disease
[Bokemeyer et al. JCO 2002]
