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J. Maessen



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    P1.08 - Poster Session/ Thymoma, Mesothelioma and Other Thoracic Malignancies (ID 224)

    • Event: WCLC 2015
    • Type: Poster
    • Track: Thymoma, Mesothelioma and Other Thoracic Malignancies
    • Presentations: 1
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      P1.08-033 - pRb and p16INK4 in Human Thymic Epithelial Tumors in Relation to Human Polyomavirus 7 (ID 249)

      09:30 - 09:30  |  Author(s): J. Maessen

      • Abstract
      • Slides

      Background:
      We have recently reported the presence of the Human polyomavirus 7 (HPyV7) in human thymic epithelial tumors as assessed by diverse molecular techniques. Here we report on the co-expression of p16, retinoblastoma protein (pRb) and phosphoralized retinoblastoma protein (phospho-Rb) in human thymic epithelial tumors in relation to HPyV7.

      Methods:
      PRB, phospho-RB and p16 expression was assessed by immunohistochemistry in 37 thymomas and 2 thymic carcinomas. 17 thymomas (46%) and 1 thymic carcinoma (50%) were recently tested positive for HPyV7. In addition, 20 follicular hyperplasias were tested.

      Results:
      Expression of pRb was observed in 35 thymomas (94.6%), in 16 thymomas (43.2%) the expression was strong. Phospho-Rb was observed in 31 thymomas (83.8%). 19 thymomas (51.4%) showed immunoreactivity for p16 of which 8 thymomas revealed very strong p16 expression. No p16 expression was detected in thymic carcinomas. In addition, no significant correlation between the presence of HPyV7 and pRb-, phospho-Rb- and p16-expression could be established. No correlation between pRb, phospho-Rb, p16 and WHO staging, Masaoka-Koga staging or the presence of MG was found. All 20 follicular hyperplasias showed expression of pRb and less expression of phospho-Rb.

      Conclusion:
      Although polyomaviruses have been shown to interact with cell cycle proteins no correlation between the presence of HPyV7 and the expression of pRb, phospho-Rb and p16 in human thymic epithelial tumors was observed. In as much HPyV7 contributes to human thymomagenesis remains to be established. Our data indicate pRb, phospho-Rb and p16 expression are rather unlikely to be involved in HPyV7 related thymomagenesis.

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    P3.08 - Poster Session/ Thymoma, Mesothelioma and Other Thoracic Malignancies (ID 226)

    • Event: WCLC 2015
    • Type: Poster
    • Track: Thymoma, Mesothelioma and Other Thoracic Malignancies
    • Presentations: 1
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      P3.08-036 - Stepwise Surgical Approach for Advanced Stage Thymoma Using Minimally Invasive Techniques (ID 649)

      09:30 - 09:30  |  Author(s): J. Maessen

      • Abstract

      Background:
      Complete surgical resection is the best prognostic factor for thymomas. In advanced stage thymomas a complete surgical resection may require mutilating approaches, may not be performed because of anticipated technical difficulties or may just be considered not achievable.

      Methods:
      Retrospective analysis of patient files from April 2004 till March 2015 showed 239 patients who underwent a thymectomy in Maastricht University Medical Center. 15 patients (6.3%) underwent thymoma resection for Masaoka-Koga advanced stage III or IV. In all cases minimally invasive techniques were employed in patients-tailored stepwise treatment approaches.

      Results:
      A 66 years old male presented with a mediastinal mass with suspected invasion of the brachiocephalic vein and the ascending aorta (figure 1). Biopsy showed thymoma type B2/B3. Resection through sternotomy in a referral hospital was abrogated as invasion of the sternum was found. After the attempted resection the patient received chemotherapy (cisplatin-etoposid) however, the thymoma did not respond. In a multidisciplinary setting we decided on a bilateral robotic-assisted dissection and if successful, subsequent sternotomy for final removal of the giant mass. Minimally invasive dissection was started from the right side. With the help of the 10x magnification of the robot camera, the thymoma was freed from the sternum, the phrenic nerve and the major vessels. Macroscopic invasion of the pericardium and the brachiocephalic vein necessitated resection of the pericardium (12 x 4 cm) and the vein (3 cm). Complete inspection using the 30 degree robotic camera of both the right and left thoracic cavity revealed the absence of pleural metastasis, and no invasion of the phrenic nerve or the lung in the left thoracic cavity. An additional left-sided approach was therefore cancelled and sternotomy was performed to remove the specimen. Lymph nodes from the positions 4,5,6,7,10,11 as well as from the subclavicular area, were harvested. Pathological examination showed a thymic carcinoma/thymoma type B3, Masaoka-Koga stage III, and confirmed a R0 resection. All lymphnodes were negative for metastasis. Postoperatively, the patient was temporarily treated with an elastic sleeve because of oedema of the left arm. As of the histology of the tumor, the patient received postoperative radiotherapy.

      Conclusion:
      Complete surgical resection in advanced stage thymomas is be possible using a stepwise surgical approach including minimally invasive techniques.