retroperitoneal tumors esp. retroperitoneal sarcoma is most challenging condition to treat in retroperitoneal region inspite of using all treatment modalities.here is brief description of its management acc. to nccn , and other text book ref.

1. RETROPERITONEAL
TUMORS
Dr. AADITYA PRAKASH
DNB Resident, Radiation Oncology
BMCHRC, Jaipur

2. RETROPERITONEAL TUMOR CLASSIFICATION

3. RETROPERITONEAL SARCOMA
EPIDEMIOLOGY
10-15% of all soft tissue sarcomas
Median age at diagnosis is 6th decade (but wide range)
Most patients present with vague abdominal complaints :-
• 80% of patients are seen with an abdominal mass
• 50% of patients report pain at the time of presentation.
Tumors typically reach large size, with median diameter ~15cm
70% occur in abdomen, 30% occur in pelvis
5% likelihood of regional nodal involvement

4. RETROPERITONEAL SPACE
Superior border: diaphragm
Inferior border: pelvic diaphragm
Lateral borders: at lateral edge of quadratus
lumborum, but lateral edge of 12th rib may be
considered, since it corresponds to the origin of
the transversus abdominus aponeurosis
Anterior border: parietal peritoneum
Posterior border: psoas, quadratus lumborum
muscles in abdomen, iliacus and obturator
internus and pyriformis in pelvis

5. RETROPERITONEAL SPACE
Composed predominately of lymphatics and loose connective tissue
Retroperitoneal organs: pancreas, kidney, adrenal glands, ureters.
Kidney, adrenal, and pancreatic tumors and malignant lympho-proliferative
processes in general do not fall into this category, even though they are located in
the same space.
Primary retroperitoneal tumors do not originate in anyretroperitoneal organ,
whether parenchymatous or not, but arise from actual tissues in the same space
or from embryonic rests found therein.

6. HISTOLOGY
Most common pathologies for retroperitoneal sarcoma are
liposarcoma and leiomyosarcoma.
Most common pathology in children is rhabdomyosarcoma.
Tumor grade prognostic for development of distant mets, local
recurrence, and decreased time to recurrence.

7. TNM STAGING
N.B:-Retroperitoneal
and pelvic sarcomas are
classified as deep
tumors
*Superficial tumor is located
exclusively above the superficial
fascia without
invasion of the fascia;
Deep tumor is located exclusively
beneath the
superficial fascia, superficial to
the fascia with invasion of or
through the
fascia, or both superficial yet
beneath the fascia.

8. Stage IV in the AJCC sixth edition of
2002

9. Workup
Liposarcoma. Contrast-enhanced axial
CT shows large right retroperitoneal
liposarcoma (arrow) composed
predominantly of fat but also has areas
of soft tissue density and calcific
components.

10. Treatment
• Surgery (en bloc resection of the tumor + involved organs ) is the primary
TREATMENT modality for retroperitoneal sarcoma.
• Radical lymphadenectomy generally indicated only if gross nodal involvement.
• <70% amenable to complete surgical resection. Positive surgical margins are
associated with high local recurrence.
• ~50% of patients with GTR (R0 or R1) experience a recurrence, and overall local
recurrence rates may be as high as 95% with sufficient follow-up.

12. Surgery
• The primary factor in outcome is complete surgical resection, followed by the grade of
the lesion.
• MSKCC:- 10-year disease specific survival for those who had incomplete resection ( 18 % )
was substantially worse than that of patients who had complete resection (53 % for
those with negative margins and 54% for those with positive margins)
• The basis for unresectability is usually the presence of peritoneal implants, extensive
vascular involvement & distant metastases.
• Partial resections or debulking procedures have been performed, but there is no
evidence that partial resection improves survival. ( Jaques DP, Coit DG, Hajdu SI, et al )

13. Pre-op RT VS. Post-op RT
• Preoperative EBRT for retroperitoneal sarcoma offers certain theoretical and practical
advantages :
 High-dose treatment could minimize the risk of tumor implantation in the peritoneal cavity
after a marginal resection by sterilizing a large number of tumor cells
 partial tumor regression could facilitate grossly complete resection
 there are favorable anatomic issues, including the tumor displacement of critical
radiosensitive organs (bowel predominantly) away from the preoperative radiation field,
thereby reducing toxicity and improving tolerance; and
 an intact peritoneum offers a mechanical barrier to tumor seeding during the time
radiotherapy is being administered before resection and division of these membranes.
• Bolla et al. found significantly worse 5-yr RT-related complication rate with PORT (23% vs.
0%) (IJROBP 2007)

14. Pre-op RT VS. Post-op RT
• Toronto Sarcoma Group/MD Anderson; 2006(Pawlik TM et al., Ann Surg Oncol
2006) :-
72 pts with intermediate- or high-grade retroperitoneal sarcoma. 75% were primary, and 25% were
recurrent.
Pts were treated preoperatively to a median dose of 45 Gy with concurrent low-dose doxorubicin.
 89% underwent laparotomy with curative intent 4–8 wks after RT.
60% had an intraop or postop boost.
MEDIAN FOLLOW-UP:- 3.4 yrs
OUTCOME:-the recurrence rate was 52% after GTR. 5-yr LRFS was 60%, DFS was 46%, and OS was
61%.
CONCLUSION:-Results compared favorably to historical controls.

15. Pre-op RT VS. Post-op RT
• MD Anderson; 2003(Pisters PW, J Clin Oncol. 2003 Aug
15;21(16):3092-7.)
Phase I:- 35 patients, potentially resectable, intermediate or high
grade retroperitoneal sarcoma. Doxorubicin QW with concurrent RT.
Dose escalation :-18/10, 30.6/17, 36/20, 41.4/23, 46.8/26, 50.4/28.
Sx: Total laparotomy in 83%. GTR (R0 or R1) in 90%.Then intra-op RT
15 Gy if R0 or R1 resection
Toxicity: Chemo-RT completed as outpatient in 89%, at 50.4 dose
level (18% Grade 3-4 nausea).
Outcome: Preop EBRT can be administered to 50.4 Gy with C.I.
doxorubicin.

16. ACOSOG Z9031
• "A randomized trial of preoperative radiation plus surgery versus
surgery alone for localized primary retroperitoneal soft tissue
sarcoma“
• The target accrual was 370 pts in 4.5 yrs. The primary endpoint was
PFS. Unfortunately, this study closed due to poor accrual.

17. Intraoperative Radiation
• Mayo Clinic; 2002 "Use of intraoperative electron beam radiotherapy in the
management of retroperitoneal soft tissue sarcomas."
87 pts (primary or recurrent), median size 10 cm; all received max surgical
resection, preop XRT (median 48.6 Gy), IOERT (median 15 Gy)
5 yr OS affected by size >10cm (28% vs 60%), amount of residual tumor (37%
gross residual, 52% microscopic or no residual). No diff b/w primary vs
recurrent.
Local control 77% at 3yrs, 59% at 5 yrs. Local control affected by amt of
residual dz (41% gross, 60% microscopic, 100% no residual).

18. Intraoperative Radiation
• Massachusetts General Hospital retrospective review (Gieschen HL et al.,
IJROBP 2001) "Long-term results of intraoperative electron beam
radiotherapy for primary and recurrent retroperitoneal soft tissue
sarcoma."
• Included 29 pts:- 16 treated with IORT (10–20 Gy with intraop electrons)
and 13 treated without IORT. All pts received 45 Gy EBRT.
• LC improved with the addition of IORT (83% vs. 61%).

19. Intraoperative Radiation
• NCI trial (Sindelar WF et al., Arch Surg 1993) :-
compared IORT + PORT to PORT alone for retroperitoneal STS.
35 pts were randomized to IORT (20 Gy) + postop EBRT (35–40 Gy) vs. PORT (50–55 Gy).
Both groups received chemo (doxorubicin/cyclophosphamide/methotrexate).
Follow-up :- 5 yrs
CONCLUSION:- there was no difference in OS between the groups (MS was 3.7 yrs with
IORT vs. 4.3 yrs with PORT). Local failure with IORT (40% IORT vs. 80% PORT). RT enteritis
occurred in 13% of pts with IORT and 50% of pts with PORT. Peripheral neuropathy was
found in 60% of pts with IORT vs. 80% of pts with PORT.

20. Adjuvant Radiation
• University of Florida; 2005 (Zlotecki RA, Am J Clin Oncol. 2005 Jun;28(3):310-6.)
• Retrospective. 50 patients treated with surgery + RT (pre-op 38%, post-op 62%).
Pre-op 50.4/42 BID @ 1.2 Gy/fx; post-op RT <50 Gy in 1.8 Gy/fx
• Outcome: 5-year OS ->SM- 69% vs. SM+ 12% (SS); low grade 77% vs. high grade
34% (SS). Local recurrent pre-op 16% vs. post-op 47% (NS)
• Toxicity: Post-op RT more frequent complications, though none severe
• Conclusion: RT appears to improve probability of local control. Pre-op Rt may be
preferred

21. Adjuvant Radiation
• French Federation Cancer Sarcoma Group; 2001 (Stoeckle E, Cancer,
2001; 92(2): 359-68.)
• reviewed 145 pts with localized nonmetastatic retroperitoneal sarcoma.
• 65% underwent GTR, and 41% had adj RT.
• OUTCOME:-5-yr OS was 46%.5-yr LRC was 55% with adj RT vs. 23% with
surgery alone.
• CONCLUSION:-Randomized trial needed to evaluate place of RT for local
control.

22. Adjuvant Radiation
• Wayne State; 2002 Int J Radiat Oncol Biol Phys, 2002; 54(2): 514-9
• 60 pts, non-metastatic retroperitoneal sarcoma; all treated with
combined surgery + XRT. XRT was either given with EBRT alone (median
52.2 Gy) or EBRT + brachy boost (42 Gy EB + 16 Gy brachy).
• 5yr DFS 53%, 10yr DFS 44%. 5yr local control 71%, 10yr 54%. Margin
status significantly correlated w/ local control.
• CONCLUSION: margin status and local control very important for RP
sarcoma long term outcome.

23. Benefit of IMRT over 3D-CRT
• Emory; 2003(Koshy M, Sarcoma. 2003;7(3-4):137-48.)
Retrospective. 10 patients with RPS and 1 inguinal sarcoma.
Prescription 50.4 Gy. Comparison of 3D-CRT and IMRT.
Outcome: Significantly better dosimetry with IMRT
Conclusion: IMRT allowed enhanced tumor coverage and better
sparing of organs at risk

24. IMRT
• Bossi A et al. (IJROBP 2007)
Prospective trial enrolling 18 pts with retroperitoneal sarcoma.
 Pts were treated with neoadj. IMRT ( 50 Gy in 25 fractions of 2 Gy/fr.)
limited to the post abdominal wall, and planning was compared to
standard RT fields. All pts successfully completed RT and surgery.
There were 2 LRs, 1 within the high-dose region and 1 marginal
recurrence that would not have been covered by the standard CTV.
CONCLUSION:- limiting the CTV to the post abdominal wall is feasible.

25. RADIOTHERAPY TECHNIQUES
• Target Volumes and Organs of Interest Definition
■ GTV ->equals the imaging-defined tumor.
■ CTV -> 1.5 to 2 cm margin on GTV(may need to be reduced to protect
vital radiosensitive viscera.)
■ PTV -> expansion volume outside the CTV that accounts for setup
error and patient/organ movement.

26. DOSE/FRACTIONATION
■ Base preoperative/postoperative dose: 45 to 50 Gy/1.8 Gy/fr.
■ Postoperative setting:-EBRT beam boost of 5.4 to 9 Gy.
■ Intraoperative boost of 10 to 15 Gy using electron-beam therapy or
brachytherapy.

27. DOSE CONSTRAINTS
• LIVER :- V50 <20% ; V25 <50%
• U/L functioning kidney :- At least two-thirds of the volume should receive
<20 Gy (most important organ to save in case of single functional kidney).
• Stomach and bowel should be limited to a maximum dose of 45 Gy.
• Volume expansions should be minimized in regions where tolerance doses
to critical structures will be reached

28. NCCN

29. NCCN

32. TOXICITY
• ACUTE SYMPTOMS :- nausea, vomiting, diarrhea, skin redness, and
fatigue. Anemia, neutropenia, and thrombocytopenia may occur,
especially with large radiation fields that often involve the adjacent
spine.
• LONG-TERM SEQUELAE OF SURGERY AND RADIATION:-small bowel
enteritis, stricture, perforation, fistula, and obstruction. Development
of nephritis is possible after radiation doses >30 Gy, with resultant
hypertension.

34. Management of Locally Recurrent
Retroperitoneal Sarcoma
• Surgery.
• For patients presenting with a second or subsequent recurrence of
retroperitoneal sarcoma, complete resection of retroperitoneal sarcoma is
usually possible in 60% to 70 % . Combined with neoadjuvant systemic therapy
or IMRT dependent on the histologic type or subtype, growth rate or time to
local recurrence, and extent of disease.
• Isolated local recurrence is most common following complete resection of a
primary retroperitoneal liposarcoma .
• Current chemotherapy is ineffective for the majority of patients with
liposarcoma and toxicity limits adequate dosing by radiation therapy, complete
surgical resection remains the most effective treatment modality.

35. • Palliative RT requires balancing expedient treatment with sufficient dose
expected to halt growth of ,or cause tumor regression. Numerous
clinical issues regarding rapidity of growth ,the status of systemic
disease, and the use of chemotherapy must be considered.
Recommended only for patients with unresectable or progressive
disease.
• Chemotherapy:-Intraperitoneal chemotherapy after debulking of
peritoneal metastases has been advocated.

36. THANK YOU