Retroperitoneal soft tissue sarcomas (RPS)

1. Retroperitoneal soft tissue
sarcomas (RPS)
Prof. Ahmed M Badheeb, MD

2. Retroperitoneal soft tissue sarcomas
(RPS)
• 10 and 15 % of (STS).
• The most common histologic types are
liposarcoma and leiomyosarcoma.

3. RPS
• RPS typically produce few symptoms until they
are large enough to compress or invade
surrounding structures;
• most commonly, they are discovered in
asymptomatic patients as an incidental
abdominal mass.

4. The preferred diagnostic work-up
• (CT) scan of the abdomen and pelvis to
evaluate the primary site and chest CT to rule
out metastatic disease to the lungs.

5. Complete resection
• Complete resection is the only standard
potentially curative treatment (although a small
number of selected patients with localized
unresectable disease may be amenable to
potential cure with charged particle radiation).
• because of the large size and anatomic
complexity of the retroperitoneum,
microscopically positive resection margins are
common, and locoregional recurrence is frequent

6. Displacement of the small bowel
• Displacement of the small bowel at the time
of surgery with omentum or prosthetic
spacers in patients who have not received
preoperative radiation may facilitate
postoperative radiation therapy (RT).

7. Adjunctive RT
• ●Adjunctive RT reduces the risk of local
recurrence, but this benefit has not yet

8. potentially resectable, small low-grade
RPS.
• we prefer initial surgery for most patients with

9. high-grade or intermediate-grade RPS
• We suggest preoperative RT, rather than initial
surgery, for patients with a high-grade or
intermediate-grade RPS and for selected patients
with a low-grade RPS (eg, one that is large [>10
cm] or appears initially unresectable or
borderline resectable) (Grade 2C).
• In this setting, we suggest RT alone rather than
chemoradiotherapy, unless the patient is being
treated in the context of a clinical trial (Grade
2C).

10. preoperative biopsy is mandatory
• For patients undergoing nonsurgical initial
treatment, a preoperative biopsy is mandatory

11. low-grade, completely resected
(margin-negative) tumor
• •If the patient is seen following resection of
an RPS, we do not suggest adjuvant RT for a
low-grade, completely resected (margin-
negative) tumor (Grade 2C).

12. Indications : postoperative RT
• intermediate/high-grade histology
• positive resection margins
• No preoperative RT, postoperative RT is a
reasonable option if this can be done within the
tolerance of the adjacent normal tissues.
• This may be facilitated by small bowel
displacement at surgery. The main benefit is a
reduction in the risk of a disease recurrence.

13. incomplete (R1 or R2)
• •For patients with an incomplete (R1 or R2)
resection, residual microscopic or macroscopic
tumor frequently abuts structures or organs
that cannot be easily or safely resected. For
these patients, we administer a postoperative,
small-field supplemental boost dose. Another
option, if the surgeon anticipates a positive
margin, is intraoperative RT (IORT) for an
additional dose of 10 to 15 Gy to areas of
grossly evident disease.

14. Adjuvant chemotherapy
• cannot be considered a standard approach for
STS at any site, including the retroperitoneum,
and we do not suggest its use outside of the
context of a clinical trial (Grade 2B).

15. Neoadjuvant
• •For patients with initially unresectable
disease, neoadjuvant (preoperative)
chemotherapy appears to be safe and
occasionally induces a radiographic response,
which may impact surgical therapy in a few
patients.

16. Preoperative chemoradiotherapy
• A role for preoperative chemoradiotherapy in patients
with RPS is not established. There has been interest in
this approach for RPS.
• However, in our view, given the lack of data from
prospective trials that preoperative
chemoradiotherapy is more effective than preoperative
RT and the potential for treatment-related toxicity, this
approach should only be used for RPS in the context of
a clinical trial by clinicians experienced with a
chemoradiotherapy approach that had been validated
in a prior clinical trial.

17. Preoperative regional hyperthermia+ systemic chemo
• Although not used in the United States, is
another therapeutic option for high-risk
primary tumors in parts of the world where it
is available (mainly Germany).
• Whether this approach is superior to surgery,
with or without RT, or chemoradiotherapy will
require a randomized trial.

18. Local recurrence
• The most significant predictor of outcome
following a local recurrence is the resectability
of the recurrent disease.
• Reresection should be attempted for an
isolated, locally recurrent tumor;
approximately 60 percent of such tumors are
potentially resectable.

19. Local recurrenc
• For patients who did not receive RT as part of
initial therapy for their sarcoma, we suggest
adjunctive RT (Grade 2C).
• For most patients, we prefer preoperative,
rather than postoperative, RT
• IORT may also be an option.

20. unresectable disease recurrence
• Repeated debulking surgery may be a
reasonable option for some patients with low-
grade liposarcomas, although complete
resection is preferred, if feasible.
• For other patients, debulking surgery does not
improve long-term survival, and it should not
be attempted.

21. high-dose charged-particle irradiation.
Some unresectable RPS:
• may be controlled long term (and possibly
cured) with the use of high-dose charged-
particle irradiation.
• However, availability of this technology is
limited to a few specialized centers.

22. Preoperative regional hyperthermia+
systemic chemo
• Although not used in the United States, is
another therapeutic option for locally
recurrent tumors in parts of the world where
it is available (mainly Germany).
• Whether this approach is superior to surgery,
with or without RT, or chemoradiotherapy will
require a randomized trial.

23. Thank you