Comparison of patterns of relapse in thymic carcinoma and thymoma

Abstract

Objective-Thymic carcinomas (TC) are considered to be more aggressive than thymomas and carry a worse prognosis. We reviewed our recent experience with the surgical management of thymic tumors and compared the outcomes and patterns of relapse between TC and thymoma.Methods-Single institution retrospective cohort study. Data included patient demographics, stage, treatment, pathologic findings, and postoperative outcomes.Results-During the period 1995-2006, 120 patients with thymic tumors underwent surgery, including 23 patients with TC and 97 patients with thymoma by the WHO 2004 histologic classification. The overall 5 year survival was significantly different between TC and thymoma (TC 53%, thymoma 89%, p=0.01). Data on relapse was available for 112 patients. The progression-free 5 year survival was also significantly different between TC and thymoma (TC 36%, thymoma 75%, p<0.01). By multivariate analysis, thymic carcinoma and incomplete resection were found to be independent predictors of progression-free survival. Relapses in TC tended to occur earlier, and occurred signficantly more frequently at distant sites than in thymoma (60% vs. 13%, p=0.01).Conclusions-Patterns of relapse differ significantly between TC and thymoma with lower progression-free survival, earlier onset and more distant relapses in TC. Given the greater propensity for distant failures, the inclusion of systemic therapy in the treatment of TC may take on greater importance. Despite significantly higher rates of distant relapse, good overall survival in TC can be achieved.

WHO types A and AB thymomas: not always benign

“…21,29 Patients with larger tumors appear to have worse prognoses. 11,17,21,48 In this study, tumors 48 cm had 22 were not able to confirm the prognostic impact of the 8 cm cutoff; this may be due to the fact that there were very few large tumors in their series.…”

“…Although some promote and anticipate a benign clinical course for these tumors, 6,[12][13][14][15][16] others (ourselves included) consider all thymomas as potentially malignant neoplasms. [1][2]10,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] Many prior studies have documented malignant behavior in types A and AB thymomas. In our retrospective study of 71 cases of types A and AB thymomas (37 cases with follow-up information available), 18 patients (nine each of types A and AB) developed recurrence and or metastases.…”

“…In majority of cases, relapses have been intrathoracic, although distant sites of progression include the lung, brain, liver, and thoracic spine. 22,29,36 Importantly, in most of these studies, complete excision of the tumor was reported. Interestingly, in the study by Rieker et al, 37 the 43 patients with type A tumors had a worse outcome when compared with patients with AB (n ¼ 20) and B1 (n ¼ 24) tumors.…”

“…Thirty of the 32 patients with type AB tumors with treatment details available were treated with surgery, either alone (22) or in combination with neoadjuvant (three), adjuvant (two) chemotherapy, or radiotherapy (three). One of the remaining two patients had partial resection with chemotherapy, whereas the other received chemotherapy only.…”

Thymic epithelial tumours: from basic principles to individualised treatment strategies

“…The risk of cardiac toxicity is even more increased because of previous use of mediastinal radiotherapy and the potential development of paraneoplastic myocarditis [101]; the use of less toxic agents, including paclitaxel [97] or pemetrexed [92]. In case of recurrence, the strategy may actually primarily consist of a similar multimodal management to that conducted at time of first diagnosis, with surgery and radiotherapy in eligible cases [102][103][104][105]. Complete resection remains a major prognostic factor in this setting.…”