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Ann Thorac Surg 2006;81:1181-1182
© 2006 The Society of Thoracic Surgeons

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Correspondence

Reply

Division of Thoracic Surgery, Massachusetts General Hospital, 55 Fruit St, Blake 1570, Boston, MA 02114

(Email: wright.cameron{at}mgh.harvard.edu).

To the Editor:

The conclusions we drew from our admittedly rather modest data set of the role of radiation therapy (RT) in stage III thymomas were conservative and meant to be provocative and simulate further studies. We believe these conclusions are still valid. Dr Cesaretti [1] has added yet another reference (Zhu and colleagues [2]) that supports our conclusions rather than his own. I thank Dr Cesaretti for picking up an error in proofreading; indeed the radiation dosimetry was from our stage II patients rather than our stage III patients. The correct dose was an average of 5,040 Gy (range, 25 to 64 Gy) with 20 of 38 receiving 50 Gy or more. There is no prospective data available on a dose response relationship for RT in thymoma. The Zhu and colleagues reference [2] is seriously misquoted, and I urge students of thymoma to review this article when interpreting Dr Cesaretti's letter [1]. The conclusion of the Zhu and colleagues article (in the abstract, body, and concluding paragraph) was that disease stage and complete resection were the only independent factors that predicted survival in thymoma. They specifically stated that radiation was not a factor in survival and that extending the radiation fields did not enhance local control. In stage III patients, the 5-year local control rate was 72% with RT < 50 Gy and 65% with RT > 50 Gy (p = 0.76). The authors further concluded that the role of adjuvant RT in thymoma is not well defined, that not all completely resected patients may need RT, and that prospective trials are needed to define the role of RT in thymoma. In our review of several articles, the role of RT as an adjuvant in thymoma is quite open for debate with all but one article suggesting a questionable benefit to RT. In the absence of a prospective trial, we will never know for sure. I believe RT for thymoma as an adjuvant got started in the 1960 to 1970 era when thoracic surgery was still in its nadir with relatively poor resections done by modern standards. Just as RT has become guided by computed tomography, which clearly has better quality, so has thoracic surgery. Most recent reports from high-volume centers find little evidence that RT as an adjuvant is efficacious. In the largest study to date (Kondo and colleagues [3]) with 170 stage III patients, there was no difference in local recurrence or survival with the addition of RT. The famous PORT (Postoperative Radiotherapy) trial [4] documented that there was a decrease in survival in completely resected stage I and II lung cancers with modern RT, confirming that RT is not "free." Radiation therapy is clearly indicated in an incomplete resection and is probably indicated when the margins are very close. It is quite clear from our results and many other centers that when a complete resection is done, prolonged freedom from recurrence is possible without adjuvant RT. The precise role of RT in the adjuvant setting after a complete resection is not clear, and ideally this should be addressed in a randomized trial. Furthermore adjuvant chemotherapy should be investigated in stage III thymomas as most recurrences are pleural, and hence they are not addressed by RT.

	References

Top References

 

1. Cesaretti JA. Adjuvant radiation with modern techniques is the standard of care for stage III thymoma (letter) Ann Thorac Surg 2006;81:1180-1181.[Free Full Text]
2. Zhu G, He S, Fu X, Jiang G, Liu T. Radiotherapy and prognostic factors for thymomaa retrospective study of 175 patients. Int J Radiat Oncol Biol Phys 2004;60(4):1113-1119.[Medline]
3. Kondo K, Monden Y. Therapy for thymic epithelial tumorsa clinical study of 1,320 patients from Japan. Ann Thorac Surg 2003;76:878-885.[Abstract/Free Full Text]
4. PORT Meta-analysis Trialist Group Postoperative radiotherapy in non-small cell lung cancersystematic review and meta-analysis of individual patient data from nine randomized controlled trials. Lancet 1998;352:257-263.[Medline]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Cameron D. Wright Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Wright, C. D. Search for Related Content PubMed Articles by Wright, C. D. Related Collections Mediastinum Related Article