Comparing Multivisceral Resection with Tumor-only Resection of Liposarcoma Using the Win Ratio.

BACKGROUND: Multivisceral resection of retroperitoneal liposarcoma (LPS) is associated with increased morbidity and may not confer a survival benefit compared with tumor-only (TO) resection. We compared both approaches using a novel statistical method called the "win ratio" (WR). METHODS: Patients who underwent resection of LPS from 2004 to 2015 were identified from the National Cancer Database. Multivisceral resection was defined as removal of the primary site in addition to other organs. The WR was calculated based on a hierarchy of postoperative outcomes: 30-day and 90-day mortality, long-term survival, and severe complication. RESULTS: Among 958 patients (multivisceral 634, TO 324) who underwent resection, the median age was 63 years (interquartile range [IQR] 54-71) with a median follow-up of 51 months (IQR 30-86). There was no difference in the WR among patients who underwent TO versus multivisceral resection in the matched cohort (WR 0.82, 95% confidence interval [CI] 0.61-1.10). In patients aged 72-90 years, those who underwent multivisceral resection had 36% lower odds of winning compared with patients undergoing TO resection (WR 0.64, 95% CI 0.40-0.98). A subgroup analysis of patients classified as not having adjacent tumor involvement at the time of surgery revealed that those patients who underwent multivisceral resection had 33% lower odds of winning compared to TO resection (WR 0.67, 95% CI 0.45-0.99). CONCLUSIONS: Based on win-ratio assessments of a hierarchical composite endpoint, multivisceral resection in patients without adjacent tumor involvement may not confer improved outcomes. This method supports the rationale for less invasive resection of LPS in select patients, especially older patients.

Survival nomograms for patients with retroperitoneal soft tissue sarcoma based on the SEER database and an external cohort.

BACKGROUND: Retroperitoneal soft tissue sarcoma (RPS) is a quite rare disease,and new nomograms need to be constructed to predict the overall survival (OS) and cancer specific survival (CSS) of RPS patients. METHODS: The clinical data of patients with RPS were extracted from the Surveillance, Epidemiology, and End Results (SEER) database and authors' hospital. The LASSO method and COX proportional hazard regression were used to screen independent risk factors which were used to develop nomograms. Nomograms was evaluated in terms of discrimination by consistency index (C-index) and calibration curve. Decision curve analysis (DCA) and integrated discrimination index (IDI) were performed to assess net benefit and the improvement of model, respectively. Kaplan-Meier method and log-rank test were applied to compare the survival difference between groups. RESULTS: A total of 1164 cases were enrolled which were divided into training cohort (n = 814) and internal validation cohort (n = 350) at a 7:3 ratio. The discrimination of nomograms were good with C-index of 0.728 (95%CI = 0.704-0.752, R2 = 0.270), 0.754 (95%CI = 0.729-0.779, R2 = 0.281) for OS and CSS, respectively. Calibration curve showed good predictive accuracy of nomograms both in internal and external validation cohort, and IDI indicated that nomograms perform well than AJCC stage. Kaplan Meier curve and log-rank test uncovered statistically significance survival difference between high- and low-risk groups with P < 0.001 in terms of OS and CSS. CONCLUSION: Novel nomograms predicting the OS and CSS of RPS patients perform well in discrimination, calibration, clinical benefit and IDI. These nomograms may facilitate risk stratification and making clinical decision.

Long-term quality of life after resection of retroperitoneal soft tissue sarcoma.

INTRODUCTION: Retroperitoneal soft tissue sarcoma (RPS) is characterized by high recurrence rates. Since complete tumor resection, often necessitating multivisceral resection, enables long-term survival in both primary and recurrent disease, health related quality of life (QoL) after RPS resection has attracted increasing interest. However, data regarding this topic is limited. Here, we multidimensionally assessed long-term QoL after RPS resection. METHODS: Five previously validated (1. EORTC QLQ-C30, 2. WEMWBS, 3. FoP-Q-SF, 4. PC-PTSD, 5. Pro-CTCAE) were sent to patients having undergone resection of primary, recurrent and metastasized RPS at Heidelberg University Hospital between 10/2001 and 12/2020. Multivariable linear regression models were used to test associations between clinical/demographic variables and patient reported outcomes (PROs). RESULTS: Questionnaires were answered by 127 patients (71% response rate). The median interval between RPS diagnosis and assessment of PROs was 80 months. The overall Global Health score was 64.1 and comparable to the general German population. RPS patients reported deficits regarding emotional and social functioning, whereas physical limitations were less pronounced. Besides diarrhea, abdominal symptoms were comparable to the overall population. Tumor recurrences, the number of surgeries, multivisceral resections or postoperative complications did not significantly affect long-term QoL ratings. CONCLUSION: RPS patients rate their QoL relatively high, even after multiple and multivisceral resections. Psychosocial well-being should be monitored in follow-up sessions to offer tailored support if necessary, thus improving postoperative care.

A century of retroperitoneal soft-tissue sarcoma research: From single center experience to precision oncology? A bibliometric analysis of past, present, and future perspectives.

BACKGROUND: Increasing publication numbers in the biomedical field led to an improvement of patient care in many aspects but are challenging for scientists when integratively processing data of their fields. Using bibliometric analyses, the present study assesses the productivity and predominant topics in retroperitoneal soft-tissue sarcoma (RPS) research across the past 122 years, thereby identifying crucial questions to address in future RPS research. METHODS: Using the Web of Science Core Collection, 1018 RPS-associated publications from 1900 to 2022 were identified and analyzed regarding key bibliometric variables using the Bibliometrix R package and the VOSviewer software. RESULTS: A continuous increase in RPS-associated publication numbers can be noticed over the time, which is strongly pronounced from 2005 onwards, and is characterized by a multinationally driven collaborative clinical research focus. The research primarily reflects progression regarding surgical techniques, histology-based therapy, radiotherapy regimens, and identification of prognostic clinicopathological factors. This progression is accompanied with improved overall survival of RPS patients. However, a paucity of RPS-specific basic/translational research indicates that such research might be additionally needed to better understand the pathophysiology of RPS and with that to enable the development of personalized therapies and to further improve patient outcome. CONCLUSION: Increasing publication numbers of multinationally driven clinical RPS research are accompanied with improved overall survival of RPS patients, highlighting the importance of international collaborations to facilitate future clinical trials. However, this bibliometric analysis reveals a lack of RPS-specific basic/translational research which is needed to further improve patient outcome in the context of precision oncology.

Leiomyosarcoma arising from the ovarian vein as a gynecologic malignancy: Two case reports and a review of the literature.

Leiomyosarcoma arising from the ovarian vein has rarely been reported. Herein, we report two cases from a single institute. Given their direct connections to ovarian vessels, both leiomyosarcomas were initially suspected to be gynecological malignancies. In one case, leiomyosarcoma was discovered incidentally without any clinical symptoms; it had a close connection with the ovarian vein, was removed surgically, and the patient has survived for over 12 years. In another case, bowel obstruction caused by the tumor helped to identify metastatic leiomyosarcoma. Blood flow was supplied by the ovarian artery and grew into the lumen of the ovarian vein without invading adjacent organs. After surgical resection, the patient underwent 18 months of chemotherapy prior to palliative care. We propose that leiomyosarcoma arising from the ovarian vein should be treated as a gynecologic malignancy, especially if it develops in the lower abdomen.

The clinical significance of perioperative inflammatory index as a prognostic factor for patients with retroperitoneal soft tissue sarcoma.

BACKGROUND: The prognostic factors of retroperitoneal soft tissue sarcoma (STS) have been explored but not yet certain. This study evaluated the prognostic impact of various preoperative clinical parameters and inflammatory indices in primary STS, with a particular focus on the transition of inflammatory index before and after tumor resection in de-differentiated liposarcoma (DD-LPS). METHODS: The clinical data of 113 patients with primary retroperitoneal STS receiving tumor resection were reviewed. Six variables (neutrophils, platelets, C-reactive protein (CRP), lymphocytes, albumin, and hemoglobin) in the blood samples were measured and nine inflammatory indices (neutrophil-lymphocyte ratio (NLR), CRP-lymphocyte ratio (CLR), platelet-lymphocyte ratio (PLR), neutrophil-albumin ratio (NAR), CRP-albumin ratio (CAR), platelet-albumin ratio (PAR), HALP (hemoglobin, albumin, lymphocyte and platelet), prognostic nutrition index (PNI), and modified Glasgow Prognostic Score (mGPS)) were calculated. The prognostic value of the indices was analyzed by univariate and multivariate analyses. RESULTS: Elevated NLR, CLR, PLR, NAR, CAR, PAR, and mGPS were associated with a worse overall survival (p = 0.0124, 0.0011, 0.049, 0.0047, 0.0085, 0.0332, and 0.0086, respectively) in univariate analysis. Multivariate analysis showed that elevated CLR and DD-LPS were associated with poor overall survival (p = 0.0267 and 0.0218, respectively) in all retroperitoneal STS. In DD-LPD, patients with preoperative high CLR, whose postoperative CLR was normalized, demonstrated a favorable survival rate similar to those with preoperative low CLR. CONCLUSIONS: Elevated CLR before surgery as well as DD-LPS were poor prognostic markers for overall survival in primary retroperitoneal STS. Perioperative CLR normalization may be related to a favorable prognosis in DD-LPS.

Development and Validation of a Nomogram for Predicting Recurrence-Free Survival of Surgical Resected Retroperitoneal Liposarcoma.

BACKGROUND AND OBJECTIVES: Surgical treatment is still the mainstay of curative therapy for retroperitoneal liposarcoma (RLPS), but often recurs after surgical resection. We aimed to establish a nomogram for postoperative recurrence of RLPS based on the Asian population. METHODS: Patients after surgical resection at the South Hospital of Zhongshan Hospital/Shanghai Public Health Clinical Center between August 2011 and December 2020 were included. The enrolled patients are randomly divided into training set and test set according to the ratio of 7:3. Prognostic factors were chosen based on Akaike Information Criterion, and the nomogram was built based on Cox regression and then internally validated through calibration plots and concordance index (C-index). RESULTS: A total of 447 patients were included. Gender, age, presentation status, organ invasion and FNCLCC grade were used to build nomogram. The calibration plots showed that RFS predicted probabilities are identical to the actual RFS rates. The C-index of the nomogram was 0.703 (95% CI 0.623-0.783) in the training set and 0.695 (95% CI 0.565-0.825) in test set. CONCLUSION: The nomogram we established can accurately predict postoperative recurrence of RLPS patients for Asian population.

Outcome after surgical resection of multiple recurrent retroperitoneal soft tissue sarcoma.

INTRODUCTION: Local recurrences (LR) and distant metastases (DM) are common in retroperitoneal soft tissue sarcoma (RPS). Longer time to recurrence and resection of the recurrent lesion have been identified as beneficial prognostic factors for overall survival (OS) upon first tumor relapse. However, prognostic factors concerning OS upon subsequent recurrences are scarcely defined. In this study, we aimed to identify prognostic factors for post-relapse outcome in multiple recurrent RPS. METHODS: Patients undergoing resection of primary and recurrent RPS at the University Hospital Heidelberg were retrospectively analyzed. Multivariable Cox regression analyses were performed to identify predictors of overall, LR- and DM-free survival. Subgroup analyses were performed for liposarcoma and leiomyosarcoma patients. RESULTS: 201 patients with primary disease, 101 patients with first, 66 patients with second and 43 patients with third LR as well as 75 patients with DM were analyzed. More than 12 months to recurrence and resection of recurrence were associated with improved OS after resection of first and second LR (5-year OS for first/second LR; resection: 64%/62%, no resection: 20%/46%). Gross macroscopic incomplete resection of first (p < 0.001), second (p = 0.001), and third recurrences (p < 0.001) was an independent prognostic factor for poor OS. CONCLUSION: Development of LR and DM is frequent in RPS. Once a tumor relapsed, patients benefit from tumor resection not only in case of first, but also in case of subsequent recurrences.

Neoadjuvant irradiation of retroperitoneal soft tissue sarcoma with ions (Retro-Ion): study protocol for a randomized phase II pilot trial.

BACKGROUND: Following surgery for soft tissue sarcoma of the retroperitoneum, the predominant pattern of failure is local recurrence, which remains the main cause of death. Radiotherapy is utilized to reduce recurrence rates but the efficacy of this strategy has not been definitely established. As treatment tolerability is more favorable with preoperative radiotherapy, normofractionated neoadjuvant treatment is the current approach. The final results of the prospective, randomized STRASS (EORTC 62092) trial, which compared the efficacy of this combined treatment to that of surgery alone, are still awaited; preliminary results presented at the 2019 ASCO Annual Meeting indicated that combined treatment is associated with better local control in patients with liposarcoma (74.5% of the cohort, 11% benefit in abdominal progression free survival after 3 years, p = 0.049). Particles allow better sparing of surrounding tissues at risk, e.g., bowel epithelium, and carbon ions additionally offer biologic advantages and are preferred in slow growing tumors. Furthermore, hypofractionation allows for a significantly shorter treatment interval with a lower risk of progression during radiotherapy. METHODS AND DESIGN: We present a prospective, randomized, monocentric phase II trial. Patients with resectable or marginally resectable, histologically confirmed soft tissue sarcoma of the retroperitoneum will be randomized between neoadjuvant proton or neoadjuvant carbon ion radiotherapy in active scanning beam application technique (39 Gy [relative biological effectiveness, RBE] in 13 fractions [5-6 fractions per week] in each arm). The primary objective is the safety and feasibility based on the proportion of grade 3-5 toxicity (CTCAE, version 5.0) in the first 12 months after surgery or discontinuation of treatment for any reason related to the treatment. Local control, local progression-free survival, disease-free survival, overall survival, and quality of life are the secondary endpoints of the study. DISCUSSION: The aim of this study is to confirm that hypofractionated, accelerated preoperative radiotherapy is safe and feasible. The rationale for the use of particle therapy is the potential for reduced toxicity. The data will lay the groundwork for a randomized phase III trial comparing hypofractionated proton and carbon ion irradiation with regard to local control. TRIAL REGISTRATION: ClinicalTrials.gov NCT04219202 . Retrospectively registered on January 6, 2020.

Postoperative Outcome of Surgery with Pancreatic Resection for Retroperitoneal Soft Tissue Sarcoma: Results of a Retrospective Bicentric Analysis on 50 Consecutive Patients.

BACKGROUNDS: Multivisceral resection is the standard treatment for retroperitoneal sarcoma (RPS) during which pancreas resection may be necessary. METHODS: All consecutive patients operated for RPS with pancreatectomy in 2 expert centers between 1993 and 2018 were retrospectively analyzed. RESULTS: Fifty patients (median age: 57 years, IQR: [46-65]) with a primary (n = 33) or recurrent (n = 17) RPS underwent surgery requiring pancreas resection (distal pancreatectomy (DP) (n = 43), pancreaticoduodenectomy (PD) (n = 5), central pancreatectomy (n = 1), and atypical resection (n = 1)). Severe postoperative morbidity (Clavien-Dindo III-IV) was observed in 14 patients (28%), and 7 of them (14%) required reoperation for anastomotic bowel leakage (n = 5), gastric volvulus (n = 1), or hemorrhage (n = 1). Pancreas-related complications occurred in 25 patients (50%): 10 postoperative pancreatic fistulas (POPF) (grade A (n = 12), grade B (n = 6), grade C (n = 1)), 13 delayed gastric emptying (grade A (n = 8), grade B (n = 4), grade C (n = 1)), 1 hemorrhage (grade C). Postoperative mortality was 4% (n = 2), all following PD, caused by a massive intraoperative air embolism and by a multiple organ failure after anastomotic leakage. Pathological analysis confirmed pancreatic involvement in 17 (34%) specimens. Microscopically complete resection (R0) was achieved in 22 (44%) patients. After a follow-up of 60 months, 36 patients (75%) were still alive, among whom 27 without recurrence (56%). CONCLUSION: Pancreatic resection during RPS surgery is associated with significant postoperative morbidity and mortality. PD should be avoided whenever possible while other procedures seemed achievable without excessive morbidity and with long-term survival.

Perioperative strategy and outcome in giant retroperitoneal dedifferentiated liposarcoma-results of a retrospective cohort study.

BACKGROUND AND OBJECTIVES: Retroperitoneal liposarcoma (RPLS) are common soft tissue sarcomas of adulthood. The aim of this study is to show resectability of even giant liposarcomas and to identify factors associated with recurrence and survival in primary retroperitoneal liposarcomas. METHODS: We retrospectively reviewed the records of patients with retroperitoneal liposarcoma. Seventy-seven patients met inclusion criteria. Out of these 10 patients with primary giant, dedifferentiated retroperitoneal liposarcomas were operated with en bloc compartment resection with intention of radical resection. Treatment consisted of neoadjuvant radiochemotherapy and surgical resection or surgical resection. RESULTS: In 6 patients, neoadjuvant radiochemotherapy was performed; 3 patients were treated with surgical resection alone and 1 patient received adjuvant chemotherapy. The median diameter of tumor size was 360 mm (300 to 440 mm). Operative outcome showed complete resection in all 10 patients. Local tumor free survival was in median 19 month. Tumor recurrence was seen in 3 of 4 patients (75%) without neoadjuvant radiochemotherapy, and in 2 of 6 patients (33%) after neoadjuvant radiochemotherapy in 2 years follow-up. CONCLUSION: Even in case of giant retroperitoneal liposarcoma, complete resection is possible and remains the principal treatment. The rate of recurrence was improved in patients with neoadjuvant radiochemotherapy.

Significance of intraoperative radiation therapy and high cumulative radiation doses in retroperitoneal soft tissue sarcoma.

INTRODUCTION: In retroperitoneal soft tissue sarcoma (STS) local recurrence (LR) rates remain high despite more aggressive surgical approaches. Since wide resection margins cannot be achieved in all patients, application of intraoperative radiation therapy (IORT) has been frequently discussed. Still, the significance of IORT in multimodal treatment of retroperitoneal STS remains unclear. MATERIAL AND METHODS: Patients undergoing resection of primary or recurrent retroperitoneal STS at the University of Heidelberg Department of General, Visceral and Transplantation Surgery were retrospectively analyzed. Univariate Kaplan-Meyer and multivariate Cox regression analyses were performed to identify predictors of LR-free survival and to investigate the impact of IORT and high cumulative radiation doses. Analyses with propensity-score matched subgroups for IORT and cumulative radiation dose were performed to control for selection bias. Subgroup analyses for patients with retroperitoneal liposarcoma were likewise performed. RESULTS: 272 patients were identified. Recurrent tumors, histology of dedifferentiated liposarcoma or unclassified sarcoma and microscopically incomplete resection were associated with decreased LR-free survival. In liposarcoma, only recurrent and dedifferentiated tumors were confirmed as poor prognostic factors concerning LR. IORT and cumulative radiation doses exceeding 60 Gy did not influence LR rates (estimated 5-year LR-free survival: IORT: 39%, non-IORT: 46%; p = 0.79). CONCLUSION: In this retrospective evaluation, additional application of IORT does not significantly influence oncological outcome in retroperitoneal soft tissue sarcoma. Randomized trials are needed to clarify the benefit of IORT.

Optimal maximum duration for delaying salvage operation when recurrence of retroperitoneal liposarcoma is suspected: a single-center study.

BACKGROUND: This study was designed to identify the optimal maximum duration for delaying salvage operation when recurrence of retroperitoneal liposarcoma (LPS) is suspected. METHODS: Patients who underwent salvage operation at Samsung Medical Center for recurrent retroperitoneal LPS from January 2000 to December 2015 were reviewed. The time interval between recurrence and operation for recurrence was divided by 1, 2 or 3 months. A Cox proportional-hazards model was used to analyze factors related to disease-free survival along with recurrence-to-operation interval divided by 1, 2 or 3 months. RESULTS: The 1-, 3-, and 5-year disease-free survival rates were 43.2%, 15.6% and 13.4%, respectively. FNCLCC grade (p = 0.023) and recurrence-to-operation interval divided by 3 months (p = 0.003) were significant factors associated with recurrence. FNCLCC grade 2 (HR 1.940, CI 0.935-4.026, p = 0.238) and grade 3 (HR 4.049, CI 1.767-9.281, p = 0.007) showed increased risk compared to grade 1. Patients who underwent salvage operation more than 3 months after recurrence showed significantly increased risk of recurrence compared to patients within 3 months (HR 2.724, CI 1.391-5.337, p = 0.003). CONCLUSIONS: Based on our analysis of recurrence-free survival, salvage operation can be delayed for less than 3 months when recurrence is suspected. A short-term follow-up imaging study should be performed within this period.

Hibernation of masses suspected to be remnant tumors after surgical resection of retroperitoneal liposarcoma is related to improved overall survival.

BACKGROUND: Although complete surgical resection is considered the best treatment for retroperitoneal liposarcoma, it is related to a high local recurrence rate. This study analyzed patterns of recurrence of retroperitoneal liposarcoma. METHODS: Records of patients who experienced recurrence after surgery for retroperitoneal liposarcoma from January 2000 to May 2017 were analyzed. Site, number, and characteristics of recurrent mass on computed tomography were serially collected. If a mass did not change size, it was considered a hibernating mass. Potential prognostic factors for overall survival were calculated using Kaplan-Meier survival log-rank tests. RESULTS: A total of 74 patients, 28 within 6 months and 46 after 6 months, were detected as having a recurrence-suspected mass after surgery. Hibernation of a recurrence-suspected mass was found in 19 patients, 12 within 6 months and 7 after 6 months. While the presence of hibernation was not related to overall survival (P = 0.245), it was significantly related to improved survival in patients with a mass detected within 6 months (P = 0.022). Hibernation was not related to improved survival in patients with a mass detected after 6 months (P = 0.056). CONCLUSIONS: Hibernation of a recurrence-suspected mass was related to improvement of overall survival in patients with a mass detected within 6 months. This specific patient group should be monitored with care to see if the size of the mass increases. When a mass seemed to be hibernating, a favorable prognosis could be expected.

An Update on Non-extremity Soft Tissue Sarcomas.

The management of soft tissue sarcoma is challenging and varied. Centralisation of management in high volume specialist centres has revolutionised outcomes. Surgery remains the mainstay of treatment and is currently the only potentially curative therapy. Retroperitoneal soft tissue sarcoma presents a particular challenge to the surgical oncologist and the concept of extended resection to include surrounding expendable organs taken en bloc with the tumour has now largely been adopted. The use of neoadjuvant and adjuvant therapies for retroperitoneal soft tissue sarcoma is still to be established, although they are employed on a case-specific basis. Guidance on the management of retroperitoneal recurrences and distant metastatic disease is now recognised. The approach to soft tissue sarcoma of the head and neck, trunk and abdominal wall remains largely extrapolated from experience of the management of extremity soft tissue sarcoma. Secondary angiosarcoma of the breast is becoming increasingly more common and presents a particular therapeutic challenge. Continued international collaboration is essential to ensure evolution of the optimal management of this rare group of cancers.

Significant benefits in survival by the use of surgery combined with radiotherapy for retroperitoneal soft tissue sarcoma.

BACKGROUND: To report the effect of intraoperative electron beam radiotherapy (IOERT) and external beam radiotherapy (EBRT) in addition to surgery as well as to evaluate the role of resectable local recurrence for long-term prognosis. METHODS: In 53 patients who underwent surgery for retroperitoneal soft tissue sarcoma (RSTS) from 2001 to 2014 prognostic and epidemiologic factors were reviewed retrospectively to analyze their impact on survival and recurrence. RESULTS: Twenty three patients (50%) had surgery plus radiotherapy, 23 (50%) had surgery only. Histology showed 73.9% liposarcoma, 15.2% leiomyosarcoma and 6.5% pleomorphic undifferentiated sarcoma respectively. Low grade sarcoma were observed in 52.2%, high grade sarcoma in 47.8%. The latter showed a trend towards a decreased 5-year survival rate (p = 0.125). Margin status was: R0: 60.9%, R1: 23.9%, R2: 15.2%; leading to significant changes in 5-year survival rate (R0: 77.6%; R1: 70.0%; R2: 42.9%; p = 0.03). Age younger than 55 years significantly improved 5-year survival rate (p = 0.039). Patients receiving resection of multiple sarcoma recurrence showed an almost identical improved 5-year survival rate compared to patients without recurrence (no recurrence: 100.0%; single recurrence: 35.0%; multiple recurrence: 91.7%; p = 0.001). Surgery plus radiotherapy led to significantly improved survival (p = 0.04). CONCLUSIONS: There is a significant benefit in terms of 5-year survival after surgery plus some form of radiotherapy and a good prognosis for patients when the recurrence from RSTS was resected. Age older than 55 years and incomplete resection lowered 5-year survival rate significantly.

The effect of microscopic margin status on survival in adult retroperitoneal soft tissue sarcomas.

INTRODUCTION: Resection is the primary treatment for retroperitoneal (RP) soft tissue sarcomas (STS). Whether obtaining microscopically negative margins (R0) improves overall survival (OS) over microscopically positive margins (R1) remains unclear. METHODS: Using the National Cancer Data Base, we identified adult patients diagnosed with RP STS after R0 or R1 resection from 1998 to 2011. We used a multivariable logistic regression model to identify clinicopathologic factors associated with margin status, including radiotherapy receipt. To assess differences in OS, the log-rank test, Cox proportional hazards regression, and propensity score matching were used. RESULTS: We identified 4015 patients; 2593 (64.6%) underwent R0 resection and 1422 (35.4%) underwent R1 resection. The most common histology was liposarcoma (2,371, 59.1%), median age was 60 years, and median follow up was 67 months. Median OS for R0 vs. R1 patients was 92 and 70 months, respectively (log-rank p < .001). Pre-operative RT was associated with increased probability of R0 resection (68.0% vs. 57.2%, p = .012). Multivariable regression showed R0 vs. R1 resection (HR 0.70, 95% CI 0.60-0.81, p < .001) was associated with improved survival, a finding confirmed on propensity score matching. Other significant predictors of OS included low tumor grade, younger age, smaller tumor size, liposarcoma histology, and receipt of RT (HR 0.81, 95% CI 0.70-0.93, p = .016). CONCLUSIONS: Patients who undergo R0 resection for RP STS appear to experience superior OS compared with patients who had R1 resections.

Tumor lysis syndrome associated with chemotherapy in primary retroperitoneal soft tissue sarcoma by ex vivo ATP-based tumor chemo-sensitivity assay (ATP-TCA).

Tumor lysis syndrome (TLS), a result of rapid cell lysis following tumor therapy, is a well recognized complication during the treatment of rapidly growing tumors. TLS rarely occurs in solid tumors. We present a case report of TLS in a patient with primary retroperitoneal soft tissue sarcoma. TLS occurred in the patient after four days' combinational chemotherapy with cisplatin, adriamycin, and dacarbazine. These drugs were selected on the basis of an ex vivo ATP-based tumor sensitivity assay. TLS was properly controlled in the patient with concomitant remission of the sarcoma. Therefore, precautions should be taken to avoid this potentially fatal complication during treatment of solid tumors, especially with tumors highly sensitive to drugs.