[Network of specialized sarcoma centres]

Non-specialized centres see relatively few patients with rare cancers like soft tissue sarcoma. This leads to inappropriate diagnostic work-up and treatment resulting in a worse oncological outcome. We believe that modern tailor-made therapy for rare cancers requires not only the multidisciplinary expertise of specialized cancer centres but also, occasionally, the expert knowledge of an international network of specialist centres. Here, we emphasize the importance of national and international networks for the treatment of patients with rare tumours. The importance is placed in perspective using the treatment of sarcoma patients as an example.

The role of radiotherapy in the management of localized soft tissue sarcomas

The combination of radiotherapy (RT) and function-preserving surgery is the most usual contemporary approach in the management of soft tissue sarcomas (STS). Pre- and postoperative RT result in similar local control rates, as shown by a landmark trial in extremity STS. In this review, the role of RT in the management of extremity STS will be discussed, but STS in other sites, including retroperitoneal STS, will also be addressed. The focus will consider various aspects of RT including strategies to reduce the volume of tissue being irradiated, dose, scheduling, and the possible of omission of RT in selected cases. Finally, technology advances through the use of intensity-modulated radiotherapy (IMRT), image-guided IMRT, intraoperative radiotherapy (IORT) and particle therapy will also be discussed.

Oncogenesis and classification of mixed-type liposarcoma: a radiological, histopathological and molecular biological analysis

Liposarcomas are separated into clinicopathological entities with a characteristic morphological spectrum and mutually exclusive genetic alterations. Therefore, the rare occurrence of cases with combined patterns of well-differentiated liposarcoma and myxoid liposarcoma designated as mixed-type liposarcoma pose a conceptual problem. Moreover, this feature may have consequences for treatment choice and prognosis. Here, we have dissected the molecular relation of tumor components in cases of mixed-type liposarcoma. On the basis of heterogeneous preoperative magnetic resonance image (MRI) features, eight cases of mixed-type liposarcoma were selected. Preoperative biopsy samples and resection specimens were analyzed including molecular and immunohistochemical analysis on all components. As controls, cases with homogeneous MRI features and uniform aspects of myxoid liposarcoma (n = 5), round cell liposarcoma (n = 5) and well-differentiated liposarcoma (n = 5) were studied. All patients with heterogeneous MRI features showed morphological components of myxoid liposarcoma and well-differentiated liposarcoma. Real-time polymerase chain reaction showed FUS-DDIT3 fusion in both components in five of eight cases in the absence (zero of five) of MDM2 and CDK4 amplification. In three of eight patients, MDM2 and/or CDK4 were overexpressed, and amplification was shown by multiplex ligation-dependent probe amplification (MLPA) in the absence of myxoid liposarcoma translocations. All control patients showed a molecular pattern consistent with their morphological features. Therefore, mixed-type liposarcomas should not be regarded as collision tumors, but as an extreme variant of the morphological spectrum within a single biological entity, explaining the biological contradiction of mixed-type liposarcoma. For treatment stratification, detailed classification including molecular support should be performed in tumors with heterogeneous MRI features.

Added Value of Molecular Biological Analysis in Diagnosis and Clinical Management of Liposarcoma: A 30-Year Single-Institution Experience

Background

Treatment decisions and prognosis assessment for liposarcoma is based on a classification that depends on morphological and genetic features. Revisions by experienced referral pathologists are often advocated.

Methods

The process of histopathological classification in referring hospitals and subsequently in a referral center in relation to molecular biological information is evaluated. A total of 331 consecutive liposarcoma patients were evaluated for the added value of histological review at time of referral. Subsequently, cases were reclassified with implementation of present-day molecular information. For all patients, complete data on staging, treatment, and follow-up were available.

Results

Upon histological revision, 15/54 (28%) diagnoses were reclassified in the first decade, 14/65 (22%) in the second, and 14/53 (26%) in the last decade. Molecular biological analysis enabled well-differentiated liposarcoma with or without dedifferentiated component to be better recognized as such and distinguished from myxoid liposarcoma and pleomorphic liposarcoma. Inclusion of cytogenetic information resulted in reclassification after revision in 4/18 (22%) cases in the first decade, 10/38 (26%) cases in the second decade, and 19/75 (25%) cases in the last decade.

Conclusions

This study indicates that liposarcomas are heterogeneous tumors. Expert assessment and implementation of molecular biological analysis are valuable for adequate classification as a basis for treatment decisions.

Primary retroperitoneal myxoid/round cell liposarcoma is a nonexisting disease: an immunohistochemical and molecular biological analysis

Almost all primary retroperitoneal liposarcomas can be classified as well-/dedifferentiated liposarcoma. Rarely, however, primary retroperitoneal liposarcoma is classified as myxoid/round cell liposarcoma, based on the presence of myxoid areas and vascular crow's feet pattern, which has resulted in a debate on the classification of liposarcoma in the retroperitoneum. Genetically, myxoid/round cell liposarcoma and well-/dedifferentiated liposarcoma are different diseases. Myxoid/round cell liposarcoma is characterized by a translocation causing FUS-CHOP or EWSR1-CHOP fusion, whereas well-/dedifferentiated liposarcoma is characterized by an amplification of the 12q13-15 region, including MDM2 and CDK4 genes. As myxoid/round cell liposarcoma is highly radio- and chemosensitive, differentiation between subtypes is important to optimize treatment. We studied whether primary retroperitoneal liposarcomas diagnosed as myxoid/round cell liposarcoma represent molecularly true myxoid/round cell liposarcoma or are histopathological mimics and represent well-/dedifferentiated liposarcoma. Primary retroperitoneal myxoid/round cell liposarcoma (n=16) were compared to primary extremity myxoid/round cell liposarcoma (n=20). Histopathological and immunohistochemical features were studied. Amplification status of the 12q13-15 region was studied using a multiplex ligation-dependent probe amplification analysis, and FUS-CHOP or EWS-CHOP translocations were studied using RT-PCR. In primary retroperitoneal myxoid/round cell liposarcoma, MDM2 and CDK4 staining was both positive in 12 of 15 cases. In primary extremity myxoid/round cell liposarcoma, MDM2 was negative in 18/20 and CDK4 was negative in all cases. Multiplex ligation-dependent probe amplification showed the amplification of 12q13-15 region in 16/16 primary retroperitoneal myxoid/round cell liposarcomas and in 1/20 primary extremity myxoid/round cell liposarcomas. Translocation was present in all (18/18) primary extremity myxoid/round cell liposarcomas, but absent in all primary retroperitoneal myxoid/round cell liposarcomas. On the basis of immunohistochemical and molecular characteristics, apparent primary retroperitoneal myxoid/round cell liposarcoma can be recognized as well-/dedifferentiated liposarcoma with morphological features mimicking myxoid/round cell liposarcoma. In these cases, treatment should probably be specifically designed as for well-/dedifferentiated liposarcoma. Moreover, finding of myxoid/round cell liposarcoma translocations in a retroperitoneal localization is highly suggestive of metastasis and should prompt search for a primary localization outside the retroperitoneum.

Effectiveness of radiotherapy in myxoid sarcomas is associated with a dense vascular pattern

PURPOSE

Surgery and adjuvant radiotherapy (RT) have long been the standard treatment for most deep-seated sarcomas; however, since the randomized trial from the National Cancer Institute of Canada, which described similar local control for pre- vs. postoperative RT, both modalities are now widely accepted. As a group, sarcomas are classified as radiation resistant. The subgroup of myxoid liposarcoma (MLS), a sarcoma with a typical vascular crow's feet pattern, is highly radiosensitive, but a mechanism for this phenomenon is unknown. Here we describe our results with preoperative RT and propose a mechanism explaining the high sensitivity based on the distinctive vascularization pattern of MLS.

METHODS AND MATERIALS

Between 2002 and 2006, 31 sarcoma patients, including 10 with MLS, underwent preoperative RT at our institute. Resected specimens were histologically evaluated, focusing on classification, grade, and vascularization patterns.

RESULTS

Twenty sarcomas showed more than 80% pathologic response after preoperative RT. A pathologic complete response was found in all "pure" MLS specimens after preoperative RT (n = 8). There were no pathologic complete responses in the remaining sarcoma patients (n = 23), although 12 showed 80% to 90% pathologic response. In contrast to the remaining RT-resistant sarcomas, the highly responding specimens contained branching vasculature, partial thrombus formation and inflammation of medium sized arterioles, similar to the vascular changes in MLS.

CONCLUSIONS

Both MLS and sarcomas with MLS-like vasculature are highly radiosensitive. Radiation sensitivity may be explained by changes in medium-sized arterioles, obstructing the specific crow's feet vascularization and inducing hypoxia with secondary tumor cell death.

Herpes simplex virus DNA synthesis is not a decisive regulatory event in the initiation of lytic viral protein expression in neurons in vivo during primary infection or reactivation from latency

The herpes simplex virus genome can enter a repressed transcriptional state (latency) in sensory neurons of the host nervous system. Although reduced permissiveness of the neuronal environment is widely accepted as a causal factor, the molecular pathway(s) directing and maintaining the viral genome in the latent state remains undefined. Over the past decade, the field has been strongly influenced by the observations of Kosz-Vnenchak et al., which have been interpreted to indicate that, in sensory neurons in vivo, a critical level of viral DNA synthesis within the neuron is required for sufficient viral immediate-early (IE) and early (E) gene expression (M. Kosz-Vnenchak, J. Jacobson, D. M. Coen, and D. M. Knipe, J. Virol. 67:5383-5393, 1993). The levels of IE and E genes are, in turn, thought to regulate the decision to enter the lytic cycle or latency. We have reexamined this issue using new strategies for in situ detection and quantification of viral gene expression in whole tissues. Our results using thymidine kinase-null and rescued mutants as well as wild-type strains in conjunction with viral DNA synthesis blockers demonstrate that (i) despite inhibition of viral DNA replication, many neurons express lytic viral proteins, including IE proteins, during acute infection in the ganglion; (ii) at early times postinoculation, the number of neurons expressing viral proteins in the ganglion is not reduced by inhibition of viral DNA replication; and (iii) following a reactivation stimulus, the numbers of neurons and apparent levels of lytic viral proteins, including IE proteins, are not reduced by inhibition of viral DNA replication. We conclude that viral DNA replication in the neuron per se does not regulate IE gene expression or entry into the lytic cycle.

Does the combination of radiotherapy and debulking surgery favor survival in paranasal sinus carcinoma?

PURPOSE

To determine the contribution of debulking surgery on local control and survival in paranasal sinus tumors. As most patients present with locally advanced disease, the possibility of radical surgery is limited. Consequently, radiotherapy is often needed as monotherapy or as an adjunct to surgery.

METHODS AND MATERIALS

Between 1977 and 1996, 73 patients (50 male: 23 female) with a paranasal sinus carcinoma were treated. The histology distribution was as follows: squamous cell carcinoma, 55%; adenocarcinoma, 19%; adenoid cystic carcinoma, 11%; and undifferentiated carcinoma, 15%. The clinical T classification was (UICC/TNM 1997): T2 14%, T3 27%, and T4 59%. Pathological neck nodes were found in 11% of patients. Treatment consisted of surgery only in 3, chemotherapy only in 1, radiotherapy only in 18, both surgery and radiotherapy in 50 patients. One patient did not receive any treatment at all. Three patients had concurrent chemotherapy. Median follow-up was 66 months (range, 1-213 months).

RESULTS

Five-year local control (LC) was 65% with combination of radiotherapy and debulking surgery in comparison with 47% with radiotherapy alone, but this difference was not statistically significant (p = 0.58). However, combination treatment gave significantly better 5-year overall survival (OS) (60% vs. 9%; p = 0.001) and 5-year disease-free survival (DFS) (53% vs. 6%; p < 0. 0001). Cox-regression analysis showed that pathologic N status (p = 0.04), palliative intention of treatment (p = 0.018), clinical orbital invasion (p = 0.003), and orbital wall invasion (p = 0.003) were parameters significantly associated with poor local control. Total radiation dose of greater than 65 Gy (p = 0.05) and treatment consisting of radiotherapy alone (p = 0.002) were associated with worse overall survival; for disease-free survival clinical orbital invasion (p = 0.0005), age of greater than 65 years (p = 0.013) and pathologic T4 classification (p = 0.002) were significant factors for an unfavorable outcome. In 19 of 73 patients, 26 serious (mainly ophthalmological) complications were reported; in the majority of these, the visual tract was (partly) included in the treatment fields because of tumor extension. To analyze on which basis patients were selected for the combination therapy, a logistic regression was performed, concluding that clinical T4 classification (p = 0.05), radiological evidence of skull base invasion (p = 0.005), age of greater than 65 years (p = 0.026), radiological evidence of nasopharynx invasion (p = 0.02), clinical suspicion of palate invasion (p = 0.02), and radiological evidence of skin invasion (p = 0.009) were associated with choosing radiotherapy alone.

CONCLUSION

Debulking surgery of paranasal sinus malignancies followed by high-dose radiotherapy to the involved sites was associated with better survival and (although not statistically significant) local control. Patient selection, based on clinical and radiological impression of tumor extension, was the main factor explaining these favorable results. We favor this combination regimen because the surgery gives quick relief of complaints and, at the same time, offers an excellent histologically proven staging method, enabling radiotherapy to be adjusted to the involved sites, thereby decreasing the risk of complications. This can all be achieved with a very low orbital exenteration rate.

The role of radiotherapy in the local management of dermatofibrosarcoma protuberans. Soft Tissue Tumours Working Group

Dermatofibrosarcoma protuberans (DFSP), a fibrohistiocytic tumour of intermediate malignancy, has a strong tendency to recur locally. Wide local excision is the recommended treatment modality. A retrospective analysis was performed on 38 consecutive DFSP patients presenting to The Netherlands Cancer Institute, to define the role of radiotherapy. Of the 21 patients treated surgically (all with negative resection margins) seven recurred, a local control probability of 67%. Combined modality treatment was given to 17 patients. Prior to radiotherapy, these patients experienced 33 occurrences of DFSP, but after irradiation only three recurrences were seen, a local control probability of 82%. These results are in keeping with the recent literature where increasing value is being given to both adjuvant and curative radiotherapy in the local management of DFSP. We recommend radiotherapy in DFSP patients where repeated surgery may cause mutilation or functional impairment.