Sarcomes en territoire irradié : actualités

The out-of-field dose in radiation therapy induces delayed tumorigenesis by senescence evasion

A rare but severe complication of curative-intent radiation therapy is the induction of second primary cancers. These cancers preferentially develop not inside the planning target volume (PTV) but around, over several centimeters, after a latency period of 1–40 years. We show here that normal human or mouse dermal fibroblasts submitted to the out-of-field dose scattering at the margin of a PTV receiving a mimicked patient’s treatment do not die but enter in a long-lived senescent state resulting from the accumulation of unrepaired DNA single-strand breaks, in the almost absence of double-strand breaks. Importantly, a few of these senescent cells systematically and spontaneously escape from the cell cycle arrest after a while to generate daughter cells harboring mutations and invasive capacities. These findings highlight single-strand break-induced senescence as the mechanism of second primary cancer initiation, with clinically relevant spatiotemporal specificities. Senescence being pharmacologically targetable, they open the avenue for second primary cancer prevention.

[Sarcoma developed in irradiated area: Preliminary results of the SARI trial]

Radiotherapy and surgery are the two main pillars of the locoregional treatment of cancer. The risk of second malignancy is better evaluated and constitutes a major issue regarding radioprotection of the patients. Among malignant disease observed in the surviving irradiated patients, the occurrence of sarcoma is a rare event but associated with a poor outcome since the 5 year overall survival is estimated at 10 to 35 %. The SARI protocol, written in 2011, included 120 patients and 240 controlled patients, irradiated in the same conditions but without sarcoma observed during the follow up. The main objective was to identify the clinical and biological factors associated with the occurrence of such a complication. The secondary objective was to identify the dosimetric characteristics of the treatment of the primary. Preliminary results will be presented during the 2016 meeting of the French radiation oncology society.

[Radiation-induced sarcoma of the head and neck]

INTRODUCTION

Radiation-induced sarcoma (RIS) of the head and neck is a late and rare complication of cancer treatment by radiation therapy. It occurs mostly within the limits of the irradiated area. Its incidence is increasing and related to an improved survival rate of treated patients. But it does not rule out the use of radiotherapy in the treatment of this cancer.

OBSERVATION

We report two cases of sarcoma having appeared in the irradiated area, in patients treated by adjuvant radiotherapy for head and neck neoplasm.

DISCUSSION

The prognosis for this sarcoma depends mainly on how early the diagnosis is made and the quality of surgical resection. Adjuvant chemotherapy or radiotherapy can be considered. Ongoing research on the expression of RIS genes could soon lead to new treatments.

Thoracic neoplasms at the Jena reference center for soft tissue tumors

INTRODUCTION

The Jena Soft Tissue Tumor Reference Center is the major German pathology institute for consultation of malignant mesenchymal tumors. Here, we present the clinicopathological data on thoracic soft tissue tumors of a two-year period.

METHODS

The tumors were analyzed according to their localization, type (soft tissue tumor, other tumor type, non-neoplastic lesion) and biological behavior. The frequency of the defined soft tissue tumor entities were considered after categorizing the cases according to the WHO Classification of Tumors. Gender and age were also assessed.

RESULTS

In total, 1,071 cases of thoracic tumors were recorded within the 2 years. The majority were non-epithelial lesions (75.3%, n = 806/1,071), of which 68.1% (n = 549/806) were malignant or intermediate malignant. 107 non-epithelial lesions involved the lung and 37 the pleura. By far the most common lung and pleural tumors were undifferentiated sarcomas. In the lung, other frequent entities were solitary fibrous tumors, synovial sarcomas and leiomyosarcomas. We also recorded 13 non-epithelial tumors of the heart and 66 tumors of the breast with angiosarcomas being the most frequent subtype. There was a female predominance for vascular neoplasms, while men prevailed for adipocytic tumors.

CONCLUSIONS

Our study provides information about the frequency, distribution, age and gender of patients with thoracic soft tissue tumors including several rare entities. Thus, it may help in the differential diagnosis of these neoplasms. In addition, we present a model highlighting the potential progression of lung carcinoma to undifferentiated sarcoma via the process of epithelial-mesenchymal transition.

Breast sarcomas: current and future perspectives

Breast sarcomas are rare neoplasms of the breast that need to be clearly distinguished from the very common breast carcinomas and treated in a multidisciplinary manner modelled after treatment paradigms in other sarcoma locations. An increasing need to differentiate sarcoma sub-types based on molecular characteristics that will also be depicted in differential treatment sensitivities and development of specifically targeted therapies are equally valid in sarcomas in general and in breast sarcomas in particular. Of special interest in breast are sarcomas developing after breast irradiation for a previous breast carcinoma, a scenario that is increasingly common, given the increasing trends of breast conservation in the surgical treatment of breast carcinoma that necessitates the adjuvant use of radiotherapy.

[Primary mediastinal sarcomas]

INTRODUCTION

Primary sarcomas of the mediastinum are rare and account for 2 to 8% of malignant mediastinal tumours. The aim of this study is to describe their clinical and pathological characteristics.

PATIENTS AND METHODS

Fifteen cases of primary mediastinal sarcoma, diagnosed between 1993 and 2009, were reviewed retrospectively, noting the clinical, radiological and pathological findings, and the treatment given.

RESULTS

The patient population consisted of eight females and seven males with mean age of 40 years (14 to 73 years). The symptomatology was predominately respiratory. Imaging showed a mediastinal mass invading adjacent organs in nine cases. The diagnosis was made in all cases by histological examination. These 15 mediastinal sarcoma comprised 12 malignant peripheral nerve tumours, two liposarcomas and one angiosarcoma. Three were grade III, six grade II and six grade I. Ten were treated surgically, of which seven had radical resections. Associated treatments were neoadjuvant (one case) or adjuvant (one case) chemotherapy and postoperative radiotherapy (five cases). Radiotherapy was undertaken alone in three inoperable tumours. Eight patients (53%) had died.

CONCLUSION

Management of primary mediastinal sarcoma needs a multidisciplinary approach, and is based mainly on radical resection. The prognosis is poor and depends mainly on surgical excision and histological grade.