Synovial Sarcoma

SS probably represents the most frequent malignant tumor of soft tissues in adolescents and young adults, accounting for about 15-20% of all cases. The optimal treatment approach to SS remains to be determined. As for other STSs of adult age, the standard treatment for localized disease is surgery. Complete surgical resection of the primary tumor is the unquestionable mainstay of treatment. Extensive surgery with histo-logically free margins is recommended: compartment resection is the treatment of choice when feasible, otherwise wide excisions may also be accepted.

A general agreement has not yet been achieved regarding the role of adjuvant treatments. Postoperative radiotherapy has a well-defined role to improve local control after less-than-compartmental resection: after wide resection, particularly in the case of a large tumor, but also after marginal and intralesional resection. In the case of locally advanced disease, the radiotherapy sandwich technique (preoperative chemotherapy and radiotherapy, then surgery followed by adjuvant chemotherapy and a possible boost of irradiation) may be useful for shrinking the tumor and making it resectable [31].

More open questions still exist regarding the role of postoperative chemotherapy, given that the rarity of the tumor hinders the adequate accrual for a randomized trial. Over the years, completely different strategies have been worked out in pediatric oncology protocols and as compared to the adult setting. Practically speaking, in European centers, a patient aged 16 years old, enrolled in pediatric trials, was treated very differently from a 22-year-old patient. Pediatricians mutated their approach from the management of RMS: due to the quite good chemotherapy response rate in the pediatric series, SS was considered as an "RMS-like" tumor and was treated with the same protocols designed for RMS, thus giving adjuvant chemotherapy

Table 11.7 Synovial sarcoma series from the Istituto Nazionale Tumori, Milan, Italy. Treatment and results according to the different age groups (from Ferrari et al. 2004)

age

0-16 years

17-30 years

>30 years

Overall

No. of patients

46 patients

83

142

271

Tumor >5 cm

49%

60%

73%

60%

Gross resected disease

41 patients

66

108

215

% Radiotherapy

58%

45%

49%

50%

% Chemotherapy

76%

21%

15%

28%

5-year EFS

66.3%

40.5%

30.9%

40.7%

to the majority of patients, even in cases of completely excised small tumors. On the contrary, adjuvant chemotherapy was employed in adult patients mainly within trials including all histotypes, with a no-therapy control arm: therefore, adjuvant chemotherapy was rarely utilized in adults and only in the recent years has it been routinely proposed for high-risk patients (local invasiveness, large size, deep localization) [42]. What would be the most adequate strategy remains unclear. Published series reported better outcome in pediatric series than in adult studies, but all the known adverse prognostic factors are more frequent in adults (large size, local invasiveness, unresectability, proximal sites), and age per se is probably a prognostic indicator. Nevertheless, the better results obtained within pediatric protocols might also be correlated with the different therapeutic strategies adopted. The most significant pediatric experience is the multicenter analysis coordinated by the University of Texas MD Anderson Cancer Center (which combined the previously published experiences of different research groups) that showed a 5-year OS of 80% and a quite high response rate to chemotherapy (60%). Of the 219 patients, 52% were adolescents (14-20 years) and the risk of event increased 0.06 times for subsequent 1 year increase in age [43]. Concerning the role of adjuvant chemotherapy, this study did not show a clear impact of chemotherapy on survival in resected patients [43].

Conversely, data from the large series of the Istituto Nazionale Tumori of Milan, Italy, showed better out comes for patients who received adjuvant chemotherapy (5-year EFS, 55% vs. 35%) [44]. This study compared the clinical findings, the treatment modalities, and the outcome of the different age groups: as shown in Table 11.7, the EFS of grossly resected cases increased with the increase in the use of adjuvant chemotherapy. Far from a demonstration of efficacy of adjuvant chemotherapy in SS, these data would seem suggestive of a role for it [44]. By definition, SS is a high-grade sarcomas, and so this could be consistent with some suggestions regarding high-risk sarcomas coming from adult trials. SS probably stands halfway between the most typical adult STSs and pediatric small round cell sarcomas, and chemotherapy seems to play a greater role in pediatric terms compared to adult sarcomas; roughly, the response rate to chemotherapy could be estimated as around 40% for adult-type STSs, 60% for SS, and 80% for RMS and ES/pPNET. This may imply that the use of chemotherapy in all cases, regardless of prognostic stratification (as developed in previous pediatric European trials) might be considered as overtreatment: a recent pediatric Italian and German review identified a subset of patients (completely resected, tumor <5 cm) treated with adjuvant chemotherapy that showed a very low risk of metastases (48 cases, 4 local relapses, no distant relapse), suggesting that chemotherapy can be omitted in low-risk groups [45]. This will be the indication for the upcoming EpSSG protocol.

Cooperative trials involving pediatric and adults patients with SS could be warranted; moreover, a large accrual of cases could permit investigation of the role of new therapies such as Bcl-2 antisense oligonucleotide, since in most cases of SS the anti-apoptotic protein Bcl-2 (overexpression of Bcl-2 correlates with tumor growth, chemoresistance, and poor outcome in various cancers) is overexpressed.

10 Ways To Fight Off Cancer

10 Ways To Fight Off Cancer

Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.

Get My Free Ebook


Post a comment