Radiotherapy For Retroperitoneal Sarcoma Research Articles

Radiation therapy for retroperitoneal sarcoma: practice patterns in North America

BackgroundThe addition of radiation therapy (RT) to surgery in retroperitoneal sarcoma (RPS) remains controversial. We examined practice patterns in the use of RT for patients with RPS over time in a large, national cohort.MethodsPatients in the National Cancer Database (2004–2017) who underwent resection of RPS were included. Trends over time for proportions were calculated using contingency tables with Cochran-Armitage Trend test.ResultsOf 7,485 patients who underwent resection, 1,821 (24.3%) received RT (adjuvant: 59.9%, neoadjuvant: 40.1%). The use of RT decreased annually by < 1% (p = 0.0178). There was an average annual increase of neoadjuvant RT by 13% compared to an average annual decrease of adjuvant RT by 6% (p < 0.0001). Treatment at high-volume centers (OR 14.795, p < 0.0001) and tumor > 10 cm (OR 2.009, p = 0.001) were associated with neoadjuvant RT. In contrast liposarcomas (OR 0.574, p = 0.001) were associated with adjuvant RT. There was no statistically significant difference in overall survival between patients treated with surgery alone versus surgery and RT (p = 0.07).ConclusionIn the United States, the use of RT for RPS has decreased over time, with a shift towards neoadjuvant RT. However, a large percentage of patients are still receiving adjuvant RT and this mostly occurs at low-volume hospitals.

Prognostic factors in patients receiving surgery and radiation therapy for retroperitoneal sarcoma: A machine-learning analysis

BackgroundThe addition of radiation therapy to surgery for retroperitoneal sarcoma remains controversial. Improved patient selection may help identify optimal candidates for multimodality treatment. The aim of this analysis was to define prognostic factors among patients who receive radiation therapy and surgery to aid in patient selection for multimodal therapy. MethodsPatients who received radiation therapy and underwent curative-intent resection for retroperitoneal sarcoma between 2004 and 2016 were identified from a national cohort in the United States (National Cancer Database). A machine-based classification and regression tree model was used to generate similar groups of patients relative to overall survival based on preoperative factors. ResultsA total of 1,443 patients received radiation therapy in addition to surgery. Median age was 61 years old and 55.0% were female. Most patients (66%) received care at an academic or integrated network cancer program. With a median follow-up of 84 months, receipt of radiation therapy was not associated with improved overall survival (P = .81). Classification and regression tree analysis revealed a significant association between overall survival and American Joint Committee on Cancer stage group, age, tumor histology, and Charlson comorbidity score. Application of these parameters via machine learning stratified patients into 5 cohorts with distinct survival outcomes. In the most favorable cohort (Cohort 1: American Joint Committee on Cancer stage group ≤II, age ≤61, histology including fibrosarcoma, well differentiated liposarcoma, myxoid liposarcoma, and leiomyosarcoma), the 5-year overall survival was 81.7% and median overall survival was not reached; in the least favorable cohort (Cohort 6: American Joint Committee on Cancer stage group >II, age >68) where the 5-year survival was 41.3% and median overall survival was 45.2 months (P < .001 versus Cohort 1). ConclusionIn the absence of a defined survival benefit, patients with advanced American Joint Committee on Cancer stage group, older age, and medical comorbidities have relatively unfavorable overall survival after combined modality therapy and therefore stand the least to gain from the addition of radiation therapy to surgery. In contrast, younger patients with good performance status and retroperitoneal sarcoma histologies with a higher propensity for local recurrence may have the greatest opportunity to benefit from radiation therapy.

Role of Radiation Therapy in Retroperitoneal Sarcoma.

Retroperitoneal sarcoma comprises a small subset of all soft tissue sarcoma and includes various histopathologic subtypes, each with unique patterns of behavior and differential risks for local recurrence and hematogenous metastatic spread. The primary treatment modality is surgery, although even with complete macroscopic resection, recurrence is common. The rationale for the addition of radiotherapy to resection is to improve local control; however, the use of radiation therapy for retroperitoneal sarcoma is controversial, and existing data are suboptimal to guide management. Treatment decisions should be determined with multidisciplinary input and shared decision-making. When used in selected patients, radiation therapy should be delivered preoperatively; postoperative treatment is not recommended.

Role of radiation therapy for retroperitoneal sarcomas: An eight-institution study from the US Sarcoma Collaborative.

The use of radiation therapy in the treatment of retroperitoneal sarcomas has increased in recent years. Its impact on survival and recurrence is unclear. A retrospective propensity score matched (PSM) analysis of patients with primary retroperitoneal soft tissue sarcomas, who underwent resection from 2000 to 2016 at eight institutions of the US Sarcoma Collaborative, was performed. Patients with metastatic disease, desmoid tumors, and palliative resections were excluded. Total 425 patients were included, 56 in the neoadjuvant radiation group (neo-RT), 75 in the adjuvant radiation group (adj-RT), and 294 in the no radiotherapy group (no-RT). Median age was 59.5 years, 186 (43.8%) were male with a median follow up of 31.4 months. R0 and R1 resection was achieved in 253 (61.1%) and 143 (34.5%), respectively. Overall 1:1 match of 46 adj-RT and 59 neo-RT patients was performed using histology, sex, age, race, functional status, tumor size, grade, resection status, and chemotherapy. Unadjusted recurrence-free survival (RFS) was 35.9 months (no-RT) vs 33.5 months (neo-RT) and 27.2 months (adj-RT), P = .43 and P = .84, respectively. In the PSM, RFS was 17.6 months (no-RT) vs 33.9 months (neo-RT), P = .28 and 19 months (no-RT) vs 27.2 months (adj-RT), P = .1. Use of radiotherapy, both in adjuvent or neoadjuvent setting, was not associated with improved survival or reduced recurrence rate.

Radiation Therapy for Retroperitoneal Sarcomas: Influences of Histology, Grade, and Size.

Perioperative radiation therapy (RT) has been associated with reduced local recurrence in patients with retroperitoneal sarcomas (RPS); however, selection criteria remain unclear. We hypothesized that perioperative RT would improve survival in patients with RPS and would be associated with pathological factors. The National Cancer Database (NCDB) from 2004 to 2012 was reviewed for patients with nonmetastatic RPS undergoing curative intent resection. Tumor size was dichotomized at 15 cm based on 8th edition American Joint Committee on Cancer (AJCC) staging. Patients with the highest comorbidity score were excluded. Unadjusted Kaplan–Meier and adjusted Cox proportional hazards modeling analyzed overall survival (OS). Multivariable logistic regression modeled margin positivity. A total of 2,264 patients were included; 727 patients (32.1%) had perioperative radiation in whom 203 (9.0%) had radiation preoperatively. Median (IQR) RPS size was 17.5 [11.0–27.0] cm. Histopathology was high grade in 1048 patients (43.7%). Multivariable analysis revealed that perioperative radiation was independently associated with decreased mortality (HR 0.72, 95% confidence intervals (CIs) 0.62–0.84, p < 0.001), and preoperative RT was associated with reduced margin positivity (HR 0.72, 95% CI 0.53–0.97, p=0.032). Stratified survival analysis showed that radiation was associated with prolonged median OS for RPS that were high-grade (64.3 vs. 43.6 months, p < 0.001), less than 15 cm (104.1 vs. 84.2 months, p=0.007), and leiomyosarcomatous (104.8 vs. 61.8 months, p < 0.001). Perioperative radiation is independently associated with decreased mortality in patients with high-grade, less than 15 cm, and leiomyosarcomatous tumors. Preoperative radiation is independently associated with margin-negative resection. These data support the selective use of perioperative radiation in the multidisciplinary management of RPS.

Preoperative intensity modulated radiation therapy for retroperitoneal sarcoma.

The use of intensity modulated radiation therapy (IMRT) has allowed for the administration of high doses to retroperitoneal sarcomas (RSTS) while limiting toxicity to adjacent organs. The purpose of our study is to assess the outcome and toxicities of patients with RSTS treated with neo-adjuvant external beam radiation (EBRT) therapy using IMRT. This is a retrospective study of 21 patients treated with preoperative IMRT for primary or recurrent RSTS between 2005 and 2011. Overall survival (OS) and local recurrence free survival (LRFS) were computed using the Kaplan-Meier method (log-rank test). Acute and chronic toxicities were assessed using the CTCAE v. 3 criteria. The actuarial 2 and 3-year OS was 66% for both and the 5-year OS was 51%. As for LRFS it was 57% at 2 and 3-year and 51% for the 5-year LRFS. Factors predictive for local control were microscopically negative margins (p = 0.022), a median tumor diameter <5 cm (p = 0.007) and pathology of liposarcoma (p = 0.021). Furthermore, patients treated for recurrent disease fared worse (p = 0.04) in local control than patients treated for primary disease. As for OS, patients treated for Grade 1 histology had a better outcome (p = 0.05). EBRT was generally well tolerated. Acute gastrointestinal (GI) Grade 1 or 2 toxicities occurred in 33% of patients and one patient had unexplained post-radiation Grade 2 fever that resolved after tumor resection. As for chronic toxicities 24% of our patients presented Grade 1 GI toxicity and one patient presented Grade 3 small bowel stenosis not clearly due to radiation toxicity. Despite the location and volume of the tumors treated, preoperative IMRT was very well tolerated in our patients with retroperitoneal sarcoma. Unfortunately local recurrences remain common and dose escalation is to be considered.

Excellent local control with preoperative radiation therapy, surgical resection, and intra‐operative electron radiation therapy for retroperitoneal sarcoma

To examine the value of surgical resection combined with preoperative external beam radiation therapy and intraoperative radiation therapy (Surg-RT) for retroperitoneal sarcoma (RPS). Review of 63 consecutive patients with RPS from 1996 to 2011. Thirty-seven patients (59%) underwent Surg-RT and 26 (41%) had surgery alone. 51% of tumors were high grade and 36% of patients had locally recurrent disease. Final margin status was: R0 73%, R1 16%, R2 6%, and unknown 5%. Of those with R0 resections, 67% received Surg-RT. Median follow-up was 45 months. The 5-year local control rate was 89% for Surg-RT patients and 46% for surgery alone patients (P = 0.03). On multivariate analysis, Surg-RT was the only variable associated with a lower risk of LR (HR 0.19; CI 0.05-0.69, P = 0.003). The actuarial 5-year OS was 60% for patients receiving either Surg-RT or surgery alone. The combination of pre-operative radiation, surgical resection, and intraoperative radiation produces excellent local disease control for RPS. Combination therapy was associated with improved local control but not with overall survival.

Preoperative intensity modulated radiation therapy for retroperitoneal sarcoma.

322 Background: The use of intensity modulated radiation therapy (IMRT) has allowed for the administration high doses to retroperitoneal sarcomas (RSTS) while limiting toxicity to adjacent organs. The purpose of our study is to assess the outcome and toxicities of patients with RSTS treated with neoadjuvant external beam radiation (EBRT) therapy using IMRT. Methods: This is a retrospective study of 21patients treated with preoperative IMRT for primary or recurrent RSTS between 2005 and 2011. Overall survival (OS) and local recurrence free survival (LRFS) were computed using the Kaplan-Meier method (log-rank test). Acute and chronic toxicities were assessed according to the CTCAE v. 3 criteria. Results: The actuarial 3 and 5-year OS and LRFS was 66% and 51%, 57% and 41% respectively. Factors predictive for LRFS were microscopically negative margins (p=0.022), a median tumor diameter &lt; 15 cm (p=0.007) and a pathology of liposarcoma (p=0.021); however, patients treated for recurrent disease fared worse (p=0.04). As for OS, grade 1 histology was a predictive factor for better outcome (p=0.05). EBRT was generally well tolerated. Acute gastrointestinal grade 1 or 2 toxicity occurred in 33% of patients and one patient had unexplained post-radiation grade 2 fever that resolved after tumor resection. As for chronic toxicities 24% of our patients presented grade 1 gastrointestinal toxicity and one patient presented grade 3 small bowel stenosis not clearly due to radiation toxicity. Conclusions: Despite the location and volume of the tumors treated, preoperative IMRT was very well tolerated in our patients with retroperitoneal sarcoma. Unfortunately local recurrences remain common and dose escalation is to be considered.

Locoregional Recurrence After Preoperative Radiation Therapy for Retroperitoneal Sarcoma: Adverse Impact of Multifocal Disease and Potential Implications of Dose Escalation

Locoregional recurrence (LRR) rates following preoperative radiation therapy (RT) and radical resection for retroperitoneal sarcoma (RPS) are high. Targeted radiation dose escalation has been proposed as a means to decrease LRR, but is applicable only if LRRs are confined to within the RT field. We analyzed predictors for LRR and examined LRR locations to determine the potential benefit of dose escalation. For 33 patients treated with preoperative RT and radical resection, we determined high-risk tumor volumes appropriate for boost and identified the number of recurrences within this volume. Clinical and pathologic variables predictive of overall survival (OS), freedom from progression (FFP), LRR, and distant recurrence (DR) were evaluated. Median follow-up was 32.9 months. At 1 and 3 years, OS was 87 and 64 %, FFP rates were 71 and 45 %, cumulative incidences of LRR were 19 and 37 %, and of DR were 13 and 21 %. On multivariate analysis, multifocal disease was a significant predictor of increased incidence of LRR. At first relapse, 6 patients had isolated LR, 2 isolated RR, 6 isolated DR, 1 synchronous LR and RR, and 1 synchronous LR, RR, and DR. Ultimately, 4 patients (25 % of those who recurred) had isolated in-field recurrences within the hypothetical high-risk dose-painting boost volumes and that thus might have been prevented with dose-escalation. Following preoperative RT and resection, LRR rates are high and associated with multifocal disease. Preoperative dose escalation to high-risk tumor volumes may perhaps benefit only a limited subset of patients, and therefore strategies are needed to select appropriate patients for consideration of this approach.

Preoperative Intensity Modulated Radiation Therapy for Retroperitoneal Sarcoma

Preoperative Intensity Modulated Radiation Therapy for Retroperitoneal Sarcoma

The use of a tissue expander to improve the therapeutic ratio of adjuvant radiotherapy for retroperitoneal sarcoma

The use of a tissue expander to improve the therapeutic ratio of adjuvant radiotherapy for retroperitoneal sarcoma

The role of radiation in retroperitoneal sarcomas: a surgical perspective

This review focuses on the current concepts relating to the use of radiation therapy in the care of surgical patients with retroperitoneal sarcoma. Radiation therapy for retroperitoneal sarcoma patients is complex because it requires decisions on not only the timing of administration, but also the technique of delivery. Multiple studies have reported improved local recurrence-free survival in patients who received adjuvant external beam radiation therapy. Recent studies have demonstrated the efficacy of more sophisticated delivery methods for radiation therapy to deliver high dose rates while sparing surrounding normal tissues. Other recent studies have demonstrated the safety and feasibility of preoperative radiation therapy for retroperitoneal sarcoma. Preoperative radiation results in decreased local recurrence rates and minimal toxicity. The use of intraoperative radiation therapy has also been examined as a means to improve local recurrence rates, but may be associated with more radiation-related morbidity. There is good evidence that radiation therapy improves local control rates. Preoperative external beam radiation therapy may be the preferred sequence to improve tumor resectability and local-regional control with less risk of complications. Although data suggest that the addition of intraoperative radiation therapy to external beam radiation therapy improves local control, intraoperative radiation therapy may be related to additional toxicity.

Dosimetric comparison of helical tomotherapy treatment and step-and-shoot intensity-modulated radiotherapy of retroperitoneal sarcoma

Purpose To compare step-and-shoot intensity-modulated radiation therapy (SAS-IMRT) and helical tomotherapy (Tomo) dosimetry plans for patients who have received adjuvant radiation therapy for retroperitoneal sarcomas (RSTS). Methods and Materials A retrospective review was performed for seven patients who received either SAS-IMRT or Tomo as adjuvant radiation therapy for RSTS. In each case, a treatment plan of the other modality was generated so that SAS-IMRT and Tomo could be compared. Results The average percentage of clinical target volume (CTV) that received less than the prescription dose was 1.4% for Tomo compared to 3.8% for SAS-IMRT. Both SAS-IMRT and Tomo plans provided comparable and significant reductions in volume of small bowel receiving greater than 45 Gy compared to simple opposing standard radiation fields. For the ipsilateral kidney, Tomo significantly reduced the volume of kidney that received at least 15 Gy (average 22% for Tomo vs. 56% for SAS-IMRT). Conclusion Both SAS-IMRT and Tomo can encompass the large CTV often required for patients with RSTS, although Tomo provides superior dose uniformity. Both SAS-IMRT and Tomo can minimize the volume of small bowel receiving greater than 45 Gy. Tomo was superior to SAS-IMRT in minimizing the volume of ipsilateral kidney irradiated to greater than 15 Gy when the CTV is adjacent to a kidney. Dose escalation and target margin expansion may thus become realistic possibilities.

Potential for toxicity reduction using intensity modulated radiation therapy (IMRT) for retroperitoneal sarcoma

Purpose/Objective: Radiation therapy for retroperitoneal sarcoma remains challenging because of proximity to surrounding organs at risk(OAR). We report the use of IMRT in the treatment of retroperitoneal sarcomas to minimize dose to OAR while concurrently optimizing tumor dose coverage. Materials/Methods: From January 2000 to October 2002, 10 patients with retroperitoneal sarcoma and 1 with inguinal sarcoma were treated with radiation at Emory Clinic. Average patient age was 58 years. 9 patients were treated preoperatively and 2 postoperatively. Prescription dose varied from 36 Gy at 1.2 Gy BID for a re-irradiation case to 59.4 Gy at 1.5 Gy QD for a postoperative case. The majority of patients received a preoperative dose of 50.4 at 1.8 Gy qd. CT simulation was used in each patient; 3 patients were treated with three-dimensional conformal radiotherapy (3D-CRT) and 8 received MLC-based IMRT. IMRT treatment fields ranged from 8–11 and average volume treated was 3498 cc. For both techniques, the field encompassed gross tumor plus a 5 cm margin in the superior/inferior dimension and a 2 cm margin in the anterior/posterior and medial/lateral dimension; when a boost was used a field reduction with a 2 cm margin was employed. Optimal 3D-CRT plans were generated and compared with IMRT with respect to tumor coverage and OAR dose toxicity. Dose volume histograms (DVH) were compared for both the 3D-CRT and IMRT plans. Results: With IMRT, average dose to 50% of small bowel was 27 Gy with less than 9% of the bowel volume exceeding 50 Gy. Mean dose to both 50% of the left kidney and the entire left kidney was 23 Gy. 50% of the right kidney received 14.6 Gy and mean dose to the entire right kidney was 14.6 Gy. 50% of the liver received 20 Gy and the entire liver received a mean dose of 23 Gy. With 3-D CRT, average dose to 50% of small bowel was 36 Gy and 24% of the bowel volume exceeded 50 Gy. 50% of the left kidney received a mean dose of 24 Gy and mean dose to the entire left kidney was 28 Gy. 50% of the right kidney received 18 Gy and mean dose to the entire right kidney was 15 Gy. 50% of the liver received 22 Gy and the entire liver received a mean dose of 28 Gy. For the same dose constraints assigned to liver, small bowel, kidney, and PTV, IMRT resulted in improved coverage of the PTV and reduced dose to critical organs at risk. Mean dose to small bowel was decreased from 36 Gy with 3D-CRT to 27 Gy using IMRT and tumor coverage as measured by the V95 was increased from 95.3% with conventional to 98.6% using IMRT. Both the maximum and minimum doses delivered to the PTV were significantly increased by 6% and by 22 % respectively (p=.011, p=.055) resulting in better dose distribution within the tumor volume. The volume of small bowel receiving > 30 Gy was significantly decreased from 63.5% to 43.1% with IMRT compared with conventional treatment (p=.043). The volume of left kidney receiving a dose greater than 25 Gy decreased from 49% to 37% with the use of IMRT. All patients were evaluated for toxicity using the RTOG toxicity scale. The most common symptoms were nausea and vomiting and less frequently diarrhea. 7 patients developed grade 2 nausea, 3 developed grade 2 diarrhea and 1 patient with primary groin involvement experienced grade 2 skin toxicity. One patient, who had extensive liver involvement and received conventional treatment developed Grade 3 liver toxicity six months after his radiation and had to be hospitalized for management of ascites. Other than this patient, there have been no other delayed toxicities related to radiation. No GU or wound toxicities were observed and no treatment breaks were necessary. At a median follow up time of 52 weeks, there were no local recurrences and only one patient developed disease progression with distant metastasis occurring in the liver. Conclusions: IMRT for retroperitoneal sarcoma allows for enhanced tumor coverage and better sparing of dose to critical normal structures such as small bowel, liver and kidney. Escalation of dose has been shown to have a positive impact on local control for retroperitoneal sarcoma and IMRT may be an effective method to achieve this goal.

Intensity Modulated Radiation Therapy for Retroperitoneal Sarcoma:A Case for Dose Escalation and Organ at Risk Toxicity Reduction

Purpose: Radiation therapy for retroperitoneal sarcoma remains challenging because of proximity to surrounding organs at risk (OAR). We report the use of intensity modulated radiation therapy (IMRT) in the treatment of retroperitoneal sarcomas to minimize dose to OAR while concurrently optimizing tumor dose coverage. Patients and methods: From January 2000 to October 2002, 10 patients (average age 56 years) with retroperitoneal sarcoma and one with inguinal sarcoma were treated with radiation at Emory University. Prescription dose to the planning treatment volume (PTV) was commonly 50.4 at 1.8 Gy/fraction. CT simulation was used in each patient, three patients were treated with 3D-conformal treatment (3D-CRT), and the remaining eight received multi-leaf collimator-based (MLC) IMRT. IMRT treatment fields ranged from eight to 11 and average volume treated was 3498 cc. Optimal 3D-CRT plans were generated and compared with IMRT with respect to tumor coverage and OAR dose toxicity. Dose volume histograms were compared for both the 3D-CRT and IMRT plans. Results: Mean dose to small bowel decreased from 36 Gy with 3D-CRT to 27 Gy using IMRT, and tumor coverage (V95) increased from 95.3% with 3D-CRT to 98.6% using IMRT. Maximum and minimum doses delivered to the PTV were significantly increased by 6 and 22%, respectively (P = 0.011, P = 0.055). Volume of small bowel receiving > 30Gy was significantly decreased from 63.5 to 43.1% with IMRT compared with conventional treatment (P = 0.043). Seven patients developed grade 2 nausea, three developed grade 2 diarrhea, one had grade 2 skin toxicity, and one patient developed grade 3 liver toxicity (RTOG toxicity scale). No other delayed toxicities related to radiation were observed. At a median follow-up of 58 weeks, there were no local recurrences and only one patient developed disease progression with distant metastasis in the liver. Conclusions: IMRT for retroperitoneal sarcoma allowed enhanced tumor coverage and better sparing of dose to critical normal structures such as small bowel, liver, and kidney. Escalation of dose has a positive impact on local control for retroperitoneal sarcoma; IMRT may be an effective method to achieve this goal. We are evaluating preoperative dose escalation to 59.4 Gy.

Silicone implant to prevent visceral damage during adjuvant radiotherapy for retroperitoneal sarcoma

The incidence of local recurrence after surgery for retroperitoneal sarcoma is reduced by high-dose adjuvant radiotherapy but treatment is restricted by the effects of irradiation on adjacent viscera. By securing a silicone gel-filled implant (breast prosthesis) in the tumour bed after excision of the tumour, adjacent viscera are displaced from the site of maximum irradiation and may thereby be protected. We used this technique in three patients in whom excision of a retroperitoneal sarcoma was followed by high-dose adjuvant radiotherapy. Post-operative radiotherapy was well tolerated but local recurrence developed in one patient, and delayed perforation of the large bowel occurred in another. Both cases underwent further surgery at which the implant was removed. The same two cases also developed asymptomatic hydronephrosis on the side of the implant, attributed to local fibrosis.

Retroperitoneal Sarcomas: The Yale Experience and a Review of the Literature

Between 1964 and 1978, 23 patients were referred for radiation therapy for retroperitoneal sarcoma. Three patients had complete excision and negative resection margins and all survived for 5 years without recurrent disease. One patient had complete resection but positive margins, but had a local recurrence 3 1/2 years after radiation. One patient had partial excision with gross residual, and this patient survived only 17 months after an incomplete radiation treatment schedule. Ten cases had biopsy only and were then referred. We found that there were only four cases that survived longer than 1 year, and their average dose of radiation was 4,400 rads, as compared to only 2,691 rads for the remaining six. We conclude that for incompletely resected or only biopsied retroperitoneal sarcoma, doses of 4,000-5,000 rads should be given and then a re-evaluation for complete resection should be done with CT scan and re-exploration. For completely resected cases, we feel that postoperative radiation adds to the local control. We have reviewed the literature and presented the data in support of our conclusions.

Retroperitoneal sarcomas: the Yale experience and a review of the literature.

Between 1964 and 1978, 23 patients were referred for radiation therapy for retroperitoneal sarcoma. Three patients had complete excision and negative resection margins and all survived for 5 years without recurrent disease. One patient had complete resection but positive margins, but had a local recurrence 3 1/2 years after radiation. One patient had partial excision with gross residual, and this patient survived only 17 months after an incomplete radiation treatment schedule. Ten cases had biopsy only and were then referred. We found that there were only four cases that survived longer than 1 year, and their average dose of radiation was 4,400 rads, as compared to only 2,691 rads for the remaining six. We conclude that for incompletely resected or only biopsied retroperitoneal sarcoma, doses of 4,000-5,000 rads should be given and then a reevaluation for complete resection should be done with CT scan and reexploration. For completely resected cases, we feel that postoperative radiation adds to the local control. We have reviewed the literature and presented the data in support of our conclusions.