Treatment algorithm

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

resectable tumor

1st line – surgery

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ACUTE
|
resectable tumor
1st line – 

surgery

Resectability depends on tumor size, edge characteristics, apparent encapsulation, and symptoms (absence of symptoms favors an early-stage tumor).

Clinically encapsulated thymomas are resected for both pathologic diagnosis and treatment.[46] Total thymectomy (resection of the entire thymus gland) is recommended to reduce risk of recurrence, although thymomectomy with wide margins may be sufficient. There is growing data indicating that, in specialized centers with experienced surgeons, a minimally-invasive approach for noninvasive thymoma is safe and can achieve the same oncologic outcomes compared to open surgery.[54][55]​​[56][57][58][59][60][61][62]​​​​​​ Macroscopically tumor-free resection margins must be achieved. Operative morbidity and mortality are generally very low.

Consider – postoperative radiation therapy

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ACUTE
|
resectable tumor
Consider – 

postoperative radiation therapy

Treatment recommended for SOME patients in selected patient group

The pathology report together with the operating surgeon's impression determine the need for adjuvant mediastinal radiation therapy.

Masaoka-Koga stage I tumors (encapsulated tumor with no evidence of invasion) are almost invariably completely resected and do not require any adjuvant therapy (if negative margins are obtained).

Masaoka-Koga stage II tumors (microscopic or macroscopic invasion, but not invading through the mediastinal pleura or pericardium) are also almost always completely resected. Adjuvant radiation therapy can be considered for some Masaoka-Koga stage II tumors, particularly those with higher risk features such as high grade, close margins, or adherence to the pericardium.​[36][65]​ The benefit of adjuvant radiation for Masaoka-Koga stage II tumors with a negative margin is controversial.

Masaoka-Koga stage III tumors (invasion into local structures) are more likely to be incompletely resected and generally have close resection margins, even when officially pathologically "negative." Most patients with Masaoka-Koga stage III tumors are, therefore, referred for adjuvant radiation regardless of the official margin status and whether or not they received neoadjuvant chemotherapy.[66] Randomized evidence investigating the benefit of radiation therapy is lacking. Standard doses range from 45-60 Gy in the postoperative setting and 60-66 Gy in the definitive setting.[67]​ Elective nodal radiation is not standard.

Plus – medical optimization presurgery

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ACUTE
|
resectable tumor
|
with myasthenia gravis
Plus – 

medical optimization presurgery

Treatment recommended for ALL patients in selected patient group

Patients with myasthenia gravis should have formal evaluation with neurology. Medical status should be optimized before undergoing surgery because the stress of surgery can precipitate a myasthenic crisis, leading to respiratory failure.[87]

As thymoma surgery is always elective, there is sufficient time to medically optimize status. See Myasthenia gravis (Treatment approach).

locally advanced tumor

1st line – preoperative chemotherapy ± radiation therapy

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ACUTE
|
locally advanced tumor
1st line – 

preoperative chemotherapy ± radiation therapy

Once a tissue diagnosis of a locally advanced thymoma or thymic carcinoma is made, neoadjuvant chemotherapy is usually given if the tumor is thought to be resectable.[68][69][70][71]​ Definitive chemoradiation therapy may be used if the tumor is deemed unresectable from the start or after a trial of neoadjuvant chemotherapy. Occasionally, neoadjuvant chemotherapy plus radiation therapy is performed, largely on the basis of institutional preference.[73]

Commonly utilized neoadjuvant chemotherapy regimens include: cisplatin plus doxorubicin plus cyclophosphamide; cisplatin plus etoposide; cisplatin plus vincristine plus doxorubicin plus cyclophosphamide; and carboplatin plus paclitaxel (especially for patients who are not candidates for cisplatin because of baseline hearing loss, renal insufficiency, or other comorbidities).[36][71][72]​​​ Response rates to neoadjuvant chemotherapy range from 40% to 100%, and pathologic complete responses have been observed in 6% to 40%. Complete resection is achievable in 20% to 80% of patients who receive induction chemotherapy.

Occasionally neoadjuvant chemotherapy plus radiation therapy is performed largely on the basis of institutional preference.[73]

Typically, patients receive 2 to 6 cycles of neoadjuvant therapy before surgery. Patients are then reevaluated for resection following repeat chest CT.

See local specialist protocol for dosing guidelines.

Primary options

cisplatin

and

doxorubicin

and

cyclophosphamide

OR

cisplatin

and

etoposide

OR

cisplatin

and

vincristine

and

doxorubicin

and

cyclophosphamide

OR

carboplatin

and

paclitaxel

Plus – reassessment followed by surgery or radiation therapy

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ACUTE
|
locally advanced tumor
Plus – 

reassessment followed by surgery or radiation therapy

Treatment recommended for ALL patients in selected patient group

After a course of neoadjuvant therapy, patients are reevaluated for resection following repeat chest CT. Most will be able to undergo resection at this stage.

However, some locally advanced thymic tumors remain unresectable following neoadjuvant chemotherapy. In cases where the disease is confined within a reasonable radiation portal, definitive thoracic radiation therapy can lead to prolonged progression-free survival.[66][74]

Consider – postoperative radiation therapy or chemoradiation therapy

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ACUTE
|
locally advanced tumor
Consider – 

postoperative radiation therapy or chemoradiation therapy

Treatment recommended for SOME patients in selected patient group

After resection, the majority of patients will receive adjuvant mediastinal radiation therapy or combination postoperative radiation and chemotherapy, as some unresectable or partially resected tumors may benefit from a combined approach.

Plus – medical optimization presurgery

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ACUTE
|
locally advanced tumor
|
with myasthenia gravis
Plus – 

medical optimization presurgery

Treatment recommended for ALL patients in selected patient group

Medical status should be optimized before undergoing surgery because the stress of surgery can precipitate a myasthenic crisis, leading to respiratory failure.[87]

As thymoma surgery is always elective, there is sufficient time to medically optimize status. See Myasthenia gravis (Treatment approach).

ONGOING

recurrent tumor

1st line – chemotherapy or other systemic therapies

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ONGOING
|
recurrent tumor
1st line – 

chemotherapy or other systemic therapies

The most important factors associated with recurrence include stage, WHO histology, and completeness of resection.

Thymoma tends to relapse in the chest, usually in the pleura (locoregional 87%; distant 13%), whereas thymic carcinoma tends to relapse at distant sites, particularly the lung, bone, brain, and liver (distant 60%; locoregional 40%).[8][12][13][75]

Distant recurrences are usually treated with chemotherapy. Active chemotherapy agents include cisplatin, paclitaxel, etoposide, cyclophosphamide, doxorubicin, vincristine, ifosfamide, pemetrexed, and gemcitabine with or without capecitabine.[77][78]​ Combination chemotherapy may also be utilized, and this may result in higher response rates.

Targeted therapies and antiangiogenic agents are also options in the recurrent setting, including everolimus, sunitinib, and lenvatinib.[79][80][81]​ Octreotide, a somatostatin analog, is an alternative systemic therapy in recurrent thymoma.

Pembrolizumab may be considered in patients with thymic carcinoma, however, it should be used cautiously due to the higher risk of immune-related adverse events.[36][85][86] If used, it is often in the heavily-pretreated setting when other modalities may be limited, and after a thorough risk-benefit discussion is had with the patient. It is avoided in patients with thymoma.

See local specialist protocol for dosing guidelines.

Primary options

cisplatin

OR

paclitaxel

OR

etoposide

OR

cyclophosphamide

OR

doxorubicin

OR

vincristine

OR

ifosfamide

OR

pemetrexed

OR

gemcitabine

OR

gemcitabine

and

capecitabine

OR

everolimus

OR

sunitinib

OR

lenvatinib

OR

octreotide

OR

pembrolizumab

Consider – surgery and/or radiation therapy

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ONGOING
|
recurrent tumor
Consider – 

surgery and/or radiation therapy

Treatment recommended for SOME patients in selected patient group

Most locoregional recurrences are treated in a multimodal fashion; resection, chemotherapy, and radiation are each often important components of therapy.[69][82][83][84]​ Surgery is generally appropriate for disease that appears completely resectable.

Plus – medical optimization presurgery

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ONGOING
|
recurrent tumor
|
with myasthenia gravis
Plus – 

medical optimization presurgery

Treatment recommended for ALL patients in selected patient group

Patients with myasthenia gravis should have formal evaluation with neurology. Medical status should be optimized before undergoing surgery because the stress of surgery can precipitate a myasthenic crisis, leading to respiratory failure.[87]

As thymoma surgery is always elective, there is sufficient time to medically optimize status. See Myasthenia gravis (Treatment approach).

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Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer

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