Thymic Tumours in Children

Round 1

Reviewer 1 Report

In this study, Aleksandra Napieralska and Leszek Miszczyk performed a retrospective study in order to assess the long-term treatment results of children with thymic tumours. In my viewpoint, though the manuscript is mainly descriptive, it is well written and clear. Studies such as this one are undoubtedly required at a larger scale, in order to better understand and establish optimal strategies for treatment. As such, I have no further requirements from the authors.

Author Response

Thank you very much for your kind opinion. Due to the rarity of thymic tumours in children, it is very hard to carry studies on larger scale. Only multinstitutional analysis on national or international level could bring more data. However, we put all the effort to include all children consulted or treated in our hospital with thymic tumour diagnosis.

Reviewer 2 Report

This manuscript represents and excellent review of the literature in thymic tumors in children. Although this is a rare disease, I was surprised that only 8 cases occurred in Poland over 35 years. Regardless, I believe the authors offer a well written manuscript about a rare and interesting topic. Their data and results support that surgery with R0 resection is the gold standard for thymic neoplasms, particularly in children. The eloquently describe the nuances of staging and classifying pediatric thymic tumors. This is a well written manuscript detailing that combined treatment including surgery, chemotherapy, and radiotherapy offer the best results for patients with these rare tumors. 

Author Response

Thank you very much for your evaluation. Thymic tumours in children are even rarer than in adults. We are working in one of the biggest hospitals in Poland, but we did not collect the data from all the other hospitals in Poland, thus the number of paediatric patients treated due to thymic tumour in this period of time could (and for sure is) be larger. Two other studies from Poland are mentioned in Table 5.

Reviewer 3 Report

Dear Authors,

your manuscript includes interesting information on treatment of thymic tumors in children. 

Especially because only 8 patients are described here, it is very exciting and necessary to characterize these cases in detail. For this purpose, research should be done on the 3 missing thymoma subtypes concerning the WHO type. This must have been analyzed after surgical resection.
Furthermore, it is interesting to know whether the tumor was histologically confirmed before the start of therapy.
In addition, it must be clarified in 3 patients whether they died from complications of thymoma therapy or whether a tumor recurrence may have occurred. It cannot be the case that in almost 40% of the young patients no data is available for reason of death. This information in association with the present histology is necessary to evaluate possible complications and effects of the multimodal therapy concepts.

It does seem unusual to me that an ethics vote is not necessary even for retrospective study evaluation.

Author Response

Dear Authors, your manuscript includes interesting information on treatment of thymic tumors in children. Especially because only 8 patients are described here, it is very exciting and necessary to characterize these cases in detail. For this purpose, research should be done on the 3 missing thymoma subtypes concerning the WHO type. This must have been analyzed after surgical resection.

Thank you very much for your valuable comment. We would like to have the possibility to answer on your question although, patients who lack the thymoma subtype evaluation were treated in the early years of the study (1985, 1991 and 1992). According to the Polish medical law, tissues are stored in pathology department for the period of 20 years and then disposed. Since the study period have covered much longer time period, those specimens were not available. We are aware, that this is one of the major drawbacks of the study, but we were not able to collect the tissue samples and evaluate them on the purpose of this study due to mentioned legal and logistic reasons. As suggested by the Reviewer, information on that was added on page 6 (marked with red font).

Furthermore, it is interesting to know whether the tumor was histologically confirmed before the start of therapy.

Patients were referred to our cancer centre after the surgery and such information was not available in our database. The tumour tissue evaluation was performed after the surgery in all the cases.

In addition, it must be clarified in 3 patients whether they died from complications of thymoma therapy or whether a tumor recurrence may have occurred. It cannot be the case that in almost 40% of the young patients no data is available for reason of death. This information in association with the present histology is necessary to evaluate possible complications and effects of the multimodal therapy concepts.

During the follow-up four patients died. In one patient, progression of the disease occurred and she died due to the thymoma. In the second patient, Hodgkin lymphoma was diagnosed and he died due to the complications during autologous stem cell transplantation. Information that he died due to lymphoma was included at the bottom of Table 2 (marked with red font) and into the text on page 4 (red font). The other two patients were treated in years 1985 and 1991. During that time the epidemiology department did not collect the data regarding the reason of death and due to the ethical reasons we did not decide to contact with the family of the patients. During the last follow-up visit no signs of disease recurrence were observed.

It does seem unusual to me that an ethics vote is not necessary even for retrospective study evaluation.

                Thank you very much for your comment. The study was conducted in hospital which is a research institute What is more, the study covered only data collection and all the patients received standard, for the period of time, treatment, and no medical experiment was conducted. Of course, as we want to conduct the research according to good clinical practise guidelines we decided to present the study idea in front our hospital ethical board. The meeting was scheduled on 14 of December and get the approval of ethical committee. The information that the study was approved by the ethical committee (Number KB/430 -166/21) was added to article on page 3 (red font).

 

 

 

Round 2

Reviewer 3 Report

Dear authors,

 

thank your for including statements on relevant limitations in the manuscript.