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Tumor Discovery SRT with SIP planning for synovial sarcoma

One of the advantages in SIP is represented by the surprising result achieved, there is also an important need
formalization of dosimetric goals in overlap area, with the to better understand the biological mechanisms impacting
possibility of quantifying and comparing the amounts of tumor control in the context of SIP planning.
dose trade-off. On the other hand, one of the most critical
aspects of SIP planning is represented by the uncertainty in Acknowledgments
tumor control in area of dose reduction. We are greatfull with all medical physicist radioterapists
This scenario planning was particularly challenging due to and nurse at our institution who helped in planning,
the high volume of overlap between PTV and internal margin perfoming and managing side effects of the treatment.
(IM) of the stomach (33 mL). Such a high-volume overlap
was explained by the diffuse tumor abutment to the stomach Funding
and also by the high respiratory motion of the stomach itself, None.
despite the high-quality abdominal compression used and
the indication of fasting for solid and liquids. Conflict of interest

3.2. Clinical considerations The authors declare no conflicts of interest.
Management of relapsed SS in a single site generally aims, Author contributions
whenever possible, to maximize radical probability through Conceptualization: Marco Lorenzo Bonù
chemotherapy and surgery. RT in such a context classically Investigation: Marco Lorenzo Bonù, Eneida Mataj, Jacopo
presents an ancillary role. Thanks to the new advances Balduzzi, Maria Teresa Cefaratti, Gloria Pedersoli,
previously described, SRT is now an emerging treatment in Gianluca Cossali, Luca Triggiani, Davide Tomasini,
the management of metastatic sarcomas, due to a relatively Michela Buglione, Stefano Maria Magrini
higher response rate compared to normofractionated and Writing – original draft: Marco Lorenzo Bonù, Eneida Mataj
moderately hypofractionated RT. Early report showed that Writing – review & editing: Marco Lorenzo Bonù, Eneida
response rate is related to smaller lesion size (<5 cm) and low Mataj, Jacopo Balduzzi, Maria Teresa Cefaratti, Gloria
grade (G1). Limitations of the available studies include the Pedersoli, Gianluca Cossali, Luca Triggiani, Davide
small sample size, the heterogeneity concerning histological Tomasini.
subtypes, and the target sites that limit the applicability of
study conclusions to all the pathologic entities in soft tissue Ethics approval and consent to participate
sarcomas . In fact, no studies have considered the role of
[31]
SRT in the context of SS, and especially in critical sites such Not Applicable.
as upper abdomen. Consent for publication
The treatment outcome of complete response achieved The patient signed an informed consent to use anonymized
in our case is clinically significant because the mass at data for publication.
first presented poor prognostic factors (size >5 cm, poorly
differentiated, and critical site). In this case study, SIP Availability of data
planning proved to be safe and, despite the relatively short
follow-up time, effective in achieving local tumor control. Data are fully available under explicit request to the
The results are particularly important given the huge area corresponding author.
of tumor-OAR overlap and the consequent low minimum References
doses delivered to some area of PTV.
1. Khin T, Cyril F, 2014, Synovial sarcoma: defining features
4. Conclusions and diagnostic evolution. Ann Diagn Pathol, 18: 369–380.

In this case report, a SS relapsed in a critical abdominal 2. Fisher C, 1998, Synovial sarcoma. Ann Diagn Pathol,
site was managed with SRT. SIP planning ensured safety 2: 401–421.
concerning acute and late toxicity and achieved complete 3. Jo VY, Fletcher CD, 2014, WHO Classification of soft
tumor control, despite the huge trade-off between target tissue tumours: An update based on the 2013 (4 ) edition.
th
coverage and the achievement of dose constraints Pathology, 46: 95–104.
objectives. This case underlines the importance of better 4. Orbach D, Mc Dowell H, Rey A, et al., 2011, Sparing strategy
clarification of the major determinants of tumor control does not compromise prognosis in pediatric localized
in RT planning. More data are needed to confirm SIP as a synovial sarcoma: experience of the International Society of
safe and effective planning modality. Moreover, given the Pediatric Oncology, Malignant Mesenchymal Tumors (SIOP-

Volume 2 Issue 2 (2023) 6 https://doi.org/10.36922/td.356