Preoperative radiation therapy and iododeoxyuridine for large retroperitoneal sarcomas

Relevant Trials Update in Sarcomas and Gastrointestinal Stromal Tumors: What Surgeons Should Know

In the past few years, the sarcoma community has successfully completed several trials in patients with soft tissue sarcoma (STS) or gastrointestinal stromal tumor (GIST). The current review summarizes recently reported relevant trials or trial updates investigating radiotherapy, chemotherapy, and targeted therapy in patients with localized extremity or superficial trunk STS, retroperitoneal sarcoma, and GIST.

The evolution of adjuvant/neoadjuvant trials for resectable localized sarcoma

Soft-tissue sarcomas are rare tumors arising from mesenchymal tissues. As a heterogeneous group comprising more than 50 types, the development of clinical trials remains challenging. Decision-making for neoadjuvant or adjuvant chemotherapy and radiation therapy is based on the available evidence of contemporary trials and multidisciplinary clinical judgment.

Phase I and Pharmacology Study of Ropidoxuridine (IPdR) as Prodrug for Iododeoxyuridine-Mediated Tumor Radiosensitization in Advanced GI Cancer Undergoing Radiation

PURPOSE

Iododeoxyuridine (IUdR) is a potent radiosensitizer; however, its clinical utility is limited by dose-limiting systemic toxicities and the need for prolonged continuous infusion. 5-Iodo-2-pyrimidinone-2'-deoxyribose (IPdR) is an oral prodrug of IUdR that, compared with IUdR, is easier to administer and less toxic, with a more favorable therapeutic index in preclinical studies. Here, we report the clinical and pharmacologic results of a first-in-human phase I dose escalation study of IPdR + concurrent radiation therapy (RT) in patients with advanced metastatic gastrointestinal (GI) cancers.

PATIENTS AND METHODS

Adult patients with metastatic GI cancers referred for palliative RT to the chest, abdomen, or pelvis were eligible for study. Patients received IPdR orally once every day × 28 days beginning 7 days before the initiation of RT (37.5 Gy in 2.5 Gy × 15 fractions). A 2-part dose escalation scheme was used, pharmacokinetic studies were performed at multiple time points, and all patients were assessed for toxicity and response to Day 56.

RESULTS

Nineteen patients were entered on study. Dose-limiting toxicity was encountered at 1,800 mg every day, and the recommended phase II dose is 1,200 mg every day. Pharmacokinetic analyses demonstrated achievable and sustainable levels of plasma IUdR ≥1 μmol/L (levels previously shown to mediate radiosensitization). Two complete, 3 partial, and 9 stable responses were achieved in target lesions.

CONCLUSIONS

Administration of IPdR orally every day × 28 days with RT is feasible and tolerable at doses that produce plasma IUdR levels ≥1 μmol/L. These results support the investigation of IPdR + RT in phase II studies.

Radiation damage to single stranded oligonucleotide trimers labelled with 5-iodopyrimidines

The radiolysis of deoxygenated aqueous solution containing trimeric oligonucleotides labelled with iodinated pyrimidines and Tris-HCl as the hydroxyl radical scavenger leads to electron attachment to the halogenated bases that mainly results in single strand breaks. The iodinated trimers are 2-fold more sensitive to solvated electrons than the brominated oligonucleotides, which is explained by the barrier-free dissociation of the iodinated base anions. The present study fills the literature gap concerning the chemistry triggered by ionizing radiation in the iodinated pyrimidines incorporated into DNA.

The Exploitation of Low-Energy Electrons in Cancer Treatment

Given the distinct characteristics of low-energy electrons (LEEs), particularly at energies less than 30 eV, they can be applied to a wide range of therapeutic modalities to improve cancer treatment. LEEs have been shown to efficiently produce complex molecular damage resulting in substantial cellular toxicities. Since LEEs are produced in copious amounts from high-energy radiation beam, including photons, protons and ions; the control of LEE distribution can potentially enhance the therapeutic radio of such beams. LEEs can play a substantial role in the synergistic effect between radiation and chemotherapy, particularly halogenated and platinum-based anticancer drugs. Radiosensitizing entities containing atoms of high atomic number such as gold nanoparticles can be a source of LEE production if high-energy radiation interacts with them. This can provide a high local density of LEEs in a cell and produce cellular toxicity. Auger-electron-emitting radionuclides also create a high number of LEEs in each decay, which can induce lethal damage in a cell. Exploitation of LEEs in cancer treatment, however, faces a few challenges, such as dosimetry of LEEs and selective delivery of radiosensitizing and chemotherapeutic molecules close to cellular targets. This review first discusses the rationale for utilizing LEEs in cancer treatment by explaining their mechanism of action, describes theoretical and experimental studies at the molecular and cellular levels, then discusses strategies for achieving modification of the distribution and effectiveness of LEEs in cancerous tissue and their associated clinical benefit.

(Neo)adjuvant treatment in localised soft tissue sarcoma: The unsolved affair

Soft tissue sarcomas (STS) are rare and heterogeneous tumours. A correct definition of STS is imperative from the very beginning of disease management, to guide the diagnostic and imaging work-up, and help to establish the prognosis on which the therapeutic strategy will be based. Over the last few years, many efforts have been made to identify characteristics that could predict disease behaviour and to enrich the therapeutic armamentarium against the advanced disease, that is still characterised by poor prognosis. Surgery remains the milestone of treatment for localised STS, whereas many uncertainties regarding the role of adjuvant and neoadjuvant treatment persist. Some controlled evidence is available, but often conflicting and insufficient to make chemotherapy (CT) a standard practice and, currently, a common and shared strategy does not exist. The biggest question concerns the prospective identification of the subgroup of patients who would benefit the most from (neo)adjuvant therapies. In light of the growing understanding of different biologies and sensitivities of the various sarcoma subtypes, the value of histology in the selection of peri-operative treatments is one of the most intriguing topics under discussion. In this perspective, a new generation of neoadjuvant trials have been planned and are currently ongoing. The aim of this review was to rekindle interest in the long-standing topic of (neo)adjuvant CT in localised STS, providing an update on its role in sarcomas' management and highlighting future directions and consequential factors needed to further improve outcomes in this disease.

DNA Distortion Caused by Uracil-Containing Intrastrand Cross-Links

Four uracil-containing intrastrand cross-links have been detected in human cells upon UV irradiation of 5-bromouracil-containing DNA, namely 5'-G[8-5]U-3', 5'-U[5-8]G-3', 5'-A[8-5]U-3', and 5'-A[2-5]U-3'. These lesions feature unique composition and connectivity compared with other intrastrand cross-links reported in the literature. For the first time, structural information obtained using molecular dynamics (MD) simulations reveal that all four lesions distort the DNA helix, which can involve an extrahelical location of the cross-link, changes in the helical interactions of the complementary nucleotides, or disruption of hydrogen bonding in the flanking base pairs up to two positions from the cross-linked site; however, the degree of distortion varies between the cross-links, being affected by the sequence, nucleobase-nucleobase connectivity, and the purine involved. Most importantly, the relative distortion of the damaged DNA provides the first structural explanation for the observed abundances of the four uracil-containing cross-links. Furthermore, the highly distorted conformations suggest that these lesions will likely have severe implications for DNA replication and repair processes in cells.

Current concepts in multimodality therapy for retroperitoneal sarcoma

Radical surgical resection currently represents the most effective therapy for patients with retroperitoneal sarcoma. Unfortunately, margin-negative resection often mandates extirpation of multiple retroperitoneal viscera, and such operations are nonetheless fraught with high rates of locoregional recurrence. In an attempt to improve local control and ultimately survival, adjuvant strategies of radiation and chemotherapy have been increasingly employed, with promising results. To date, however, the rarity of the disease has limited large, prospective studies investigating the efficacy of these adjuvant modalities. In this article, we review the current literature pertaining to the diagnosis, staging and treatment of retroperitoneal sarcoma and demonstrate the critical need for future large, multi-institutional studies to advance our knowledge of this uncommon disease.

Preoperative radiation for retroperitoneal sarcoma is not associated with increased early postoperative morbidity

BACKGROUND AND OBJECTIVES

Preoperative radiation (PR) in the management of retroperitoneal sarcoma (RPS) is controversial. Concern for increased perioperative morbidity may influence the decision to recommend PR. Here we compare 30-day morbidity and mortality (M + M) after resection of RPS with and without PR.

METHODS

Patients undergoing resection of RPS were identified using ACS NSQIP (2005-2011). Patients with known PR status within 90 days of operation were included. Univariate and multivariate logistic regression analyses were performed to identify factors associated with M + M.

RESULTS

Of 696 patients operated on for RPS, 70 (10%) underwent PR. PR patients were younger (mean 55 vs. 61 years), more frequently had hypoalbuminemia (<3 g/dl; 19% vs. 10%), concomitant kidney (29% vs. 18%), or pancreas resections (11% vs. 5%), longer operations (mean 327 vs. 253 min), and increased transfusion requirements (mean 4.1 vs. 2.1 units, each P < 0.05). Despite these differences, the M + M rate (31% with vs. 30% without PR, P = 0.75) was comparable between the two groups. After adjustment for confounders, no association was identified between PR and M + M.

CONCLUSIONS

In a national cohort of RPS patients, PR is infrequently utilized. Despite the increased prevalence of multiple risk factors, PR patients do not have an increased 30-day postoperative M + M.

Retroperitoneal sarcomas- a challenging problem

Retroperitoneal sarcomas are relatively rare tumours and usually present in a locally advanced stage. Liposarcoma is the most common histopathology. If operable, surgery is the treatment of choice. The role of adjuvant chemotherapy or radiotherapy is not yet defined. Advanced cases are treated by chemotherapy. The prognosis is poor in patients with positive resection margins, high-grade tumours and recurrent tumours.

Formation mechanism and structure of a guanine-uracil DNA intrastrand cross-link

The formation and structure of the 5'-G[8-5]U-3' intrastrand cross-link are studied using density functional theory and molecular dynamics simulations due to the potential role of this lesion in the activity of 5-halouracils in antitumor therapies. Upon UV irradiation of 5-halouracil-containing DNA, a guanine radical cation reacts with the uracil radical to form the cross-link, which involves phosphorescence or an intersystem crossing and a rate-determining step of bond formation. Following ionizing radiation, guanine and the uracil radical react, with a rate-limiting step involving hydrogen atom removal. Although cross-link formation from UV radiation is favored, comparison of calculated reaction thermokinetics with that for related experimentally observed purine-pyrimidine cross-links suggests this lesion is also likely to form from ionizing radiation. For the first time, the structure of 5'-G[8-5]U-3' within DNA is identified by molecular dynamics simulations. Furthermore, three conformations of cross-linked DNA are revealed, which differ in the configuration of the complementary bases. Distortions, such as unwinding, are localized to the cross-linked dinucleotide and complementary nucleotides, with minimal changes to the flanking bases. Global changes to the helix, such as bending and groove alterations, parallel cisplatin-induced distortions, which indicate 5'-G[8-5]U-3', may contribute to the cytotoxicity of halouracils in tumor cell DNA using similar mechanisms.

Targeted endoradiotherapy using nucleotides

Increased cellular proliferation is an integral part of the cancer phenotype. Hence, the sustained and continued demand on supply of DNA building blocks during the DNA replication presents a potential target for therapeutic intervention. For this propose, the α and Auger electron emitting nucleotides analogs are attractive for targeted endoradiotherapy, given that DNA of malignant cells is selectively addressed. This review summarizes development and preclinical and clinical studies of endoradiotherapeutic acting nucleoside analogs with a special focus on thymidine analogs.

Paclitaxel-eluting polymer film reduces locoregional recurrence and improves survival in a recurrent sarcoma model: a novel investigational therapy

BACKGROUND

Locoregional recurrences occur in up to 50% of patients after macroscopically complete (R0/R1) resections of abdominal, pelvic, and retroperitoneal sarcomas. Efficacy of a drug-eluting polymer film in reducing locoregional recurrence rates was assessed in a murine recurrent sarcoma model.

METHODS

Poly(glycerol monostearate-co-caprolactone) polymer films were synthesized with and without 300 μg paclitaxel (Pax-film and unloaded film). Cytotoxicity was assessed against CS-1 (human chondrosarcoma) cells in vitro and in vivo in nude mice. Following R0/R1 resection of primary subcutaneous tumors, mice were blindly randomized to: (1) Pax-film implant, (2) unloaded film implant, (3) paclitaxel 300 μg IV (Pax IV), or (4) no other therapy ("untreated"). Locoregional recurrence, overall survival (OS), and tumor mitotic index were evaluated.

RESULTS

Pax-films, but not unloaded films, reduced CS-1 viability in vitro for >50 days (P < 0.001). In vivo, locoregional recurrence was observed in 2 of 12 Pax-film mice (17%), 9 of 13 unloaded film mice (69%), 8 of 9 Pax IV mice (89%), and 7 of 8 untreated mice (88%) (P < 0.01). Median OS was 81, 64, 48, and 56 days, respectively. Paclitaxel levels in local tissues were 50- to 300-fold greater in Pax-film mice compared with Pax IV mice. Tumor mitotic index adjacent to Pax-films was significantly lower than adjacent to unloaded films.

CONCLUSIONS

Tumor bed implantation of Pax-films after R0/R1 resection is superior to Pax IV as evidenced by reduced locoregional recurrence and improved OS in a murine recurrent sarcoma model. Continuous local drug exposure via polymer films represents a potentially novel approach for treatment of locally aggressive sarcomas.

Recent progress in the management of retroperitoneal sarcoma

Retroperitoneal sarcomas (RPS) are rare tumours that typically present late and carry a poor prognosis even following grossly complete resection. In an attempt to improve the outlook for patients with RPS, sarcoma specialists have employed various adjuvant therapies, including extermal beam radiation, intraoperative radiation, brachyradiation and systemic chemotherapy. This article reviews the presentation and prognosis of RPS, and focuses on the results of new treatment strategies compared with conventional management.

A Medline search of the English literature was performed to identify all retrospective and prospective reports relating to the management of adult RPS published since 1980. Series that did not analyse RPS separately from other intra-abdominal or extra-abdominal sarcomas or other malignancies were excluded, and information on investigation, presentation, prognostic factors, treatment and outcome was extracted from the remaining reports. Survival and local control data were collected from reports that contained at least 30 cases of RPS (n = 31).

While surgical resection remains the cornerstone of treatment for RPS, the majority of patients will relapse and die from sarcoma within 5 years of resection. Adjuvant radiation may improve these results, but further trials are required to definitively demonstrate its benefit. Possible reasons for the failure of conventional treatment are discussed, and alternative strategies designed to overcome these obstacles are presented.

Aggressive surgical policies in a retrospectively reviewed single-institution case series of retroperitoneal soft tissue sarcoma patients

PURPOSE

To explore whether the adoption of a systematic attempt to perform wider resections may lead to prognostic improvements in retroperitoneal soft tissue sarcoma (RSTS).

PATIENTS AND METHODS

Two hundred eighty-eight consecutive patients who were surgically treated at a single referral center were analyzed. Because a shift toward a systematic, more aggressive surgical approach (ie, liberal en bloc resection of adjacent organs) was in place from 2002 onward, patients were divided in two groups accordingly. Overall survival, crude cumulative incidence (CCI) of local recurrence, and distant metastases were estimated. Univariable and multivariable analyses were carried out.

RESULTS

Patients who underwent operation in the early period had a 5-year local recurrence rate of 48% compared with 28% for patients who were treated in the recent period. The number of distant metastases was greater in the recent group (22% v 13%), and overall survival was similar. In addition to the period of treatment, important independent determinants for local recurrence-free survival were histologic grade, histologic subtype, and radiation therapy. Overall, liposarcomas and grades 1 to 2 tumors had the greatest local benefit at 5 years.

CONCLUSION

In a single institution, the adoption of a policy of more liberal visceral en bloc resections was paralleled by greater local control. This benefit might translate into a prognostic improvement only on a longer follow-up for patients with a more indolent disease, whereas systemic failures seem to be the main problem in high-grade tumors. Radiation therapy could add some additional benefit to local outcome and possibly to survival.

Diagnosis and management of soft tissue sarcomas

STS are a heterogeneous group of malignant tumors that pose significant management challenges. The cornerstone of therapy for patients who have primary STS remains margin-negative resection. Adjuvant radiotherapy has been shown to reduce the risk of recurrence for extremity and trunk STS, although its role for retroperitoneal STS remains to be defined. Neoadjuvant radiotherapy has some theoretic advantages to postoperative radiation, but its exact role has yet to be determined. Chemotherapy is usually reserved for chemotherapy-sensitive histologic subtypes and for patients who have metastatic STS.

The prognostic impact of dedifferentiation in retroperitoneal liposarcoma: a series of surgically treated patients at a single institution

BACKGROUND

A series of patients with well differentiated (WD)/dedifferentiated (DD) retroperitoneal liposarcoma (RLS) was studied to evaluate the prognostic value of the presence, extension, and grade of the DD component.

METHODS

Among 148 patients with RLS who underwent surgery over 20 years, the authors retrieved data on patients who had localized WD/DD RLS. For the current analysis, patients were included only if they had primary disease or a first recurrence at their initial presentation. The DD component, when present, was graded according to National Federation of Centers in the Fight Against Cancer (FNCLCC) criteria, and the extension of the DD component was described as a percentage. Univariate and multivariate analyses were carried out for local recurrence-free survival (LRFS), event-free survival (EFS), and disease-specific survival (DSS).

RESULTS

Of 93 patients who were identified, 36 patients (39%) had WD RLS, and 57 patients (61%) had DD RLS. The median follow-up was 71 months (range, 28-132 months). Seven patients (7.5%) developed distant metastases, including 5 patients who had DD RLS. The 5-year DSS rate was 42% in patients with DD RLS and 71.6% in patients with WD RLS (P = .018). The corresponding rates for LRFS were 22% and 43.3%, respectively (P = .007). The presence of the DD component and its FNCLCC grade were independent prognostic factors for DSS and LRFS. The administration of radiation therapy was associated independently with better LRFS.

CONCLUSIONS

Patients with high-grade DD RLS had a worse prognosis in terms of both DSS and LRFS. The extension of the DD component and its mitotic index were relevant for EFS. The results indicated that radiation therapy may improve LRFS. These data may help stratify the risk of recurrence for patients with RLS. Clinical studies on new multimodality approaches are warranted.

Long-Term Outcomes After Radiotherapy for Retroperitoneal and Deep Truncal Sarcoma

PURPOSE

To determine the long-term outcomes after multimodality treatment of retroperitoneal, pelvic, and deep truncal sarcomas and to identify the factors associated with local control (LC), distant metastasis (DM), and overall survival (OS).

METHODS AND MATERIALS

A total of 85 patients with retroperitoneal, pelvic, and deep truncal sarcomas were treated with radiotherapy (RT) between 1987 and 2005. A retrospective analysis of LC, DM, and OS was conducted using log-rank and Cox regression statistical methods.

RESULTS

The 2- and 5-year LC, DM, and OS rates were 66% and 51%, 38% and 58%, and 70% and 34%, respectively. Negative surgical margins and a higher radiation dose were associated with greater LC rates on both univariate and multivariate analyses, and female gender was significantly associated with greater LC on multivariate analysis only. None of the analyzed risk factors was significantly associated with DM, although patients with high-grade tumors showed a trend toward an increased risk of DM. Gross residual disease after resection and high tumor grade were associated with worse OS rates on univariate and multivariate analyses, and male gender was significantly associated with worse OS on multivariate analysis only. A time-dependent analysis of LC in relation to DM demonstrated that patients with local failure had a hazard ratio of 19.7 for DM compared with patients without local failure (p < 0.0001). Of the 85 patients, 5 and 8, respectively, had clinically significant acute and late toxicity.

CONCLUSION

The results of this study emphasize the importance of LC in patients with retroperitoneal sarcoma. Radiation dose escalation or radiosensitization strategies to enhance LC are warranted.

The role of radiation in retroperitoneal sarcomas: a surgical perspective

PURPOSE OF REVIEW

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.

RECENT STUDIES

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.

SUMMARY

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.

Local Management of Adult Soft Tissue Sarcomas

Soft tissue sarcomas (STS) are rare tumors classified into multiple histological subtypes and categorized into four sites: extremity and trunk, head and neck, retroperitoneal, and visceral, the latter now predominantly consisting of gastrointestinal stromal tumors. Well-planned, complete surgical resection is the mainstay of curative therapy for tumors at each of these sites. The success of surgery alone in controlling disease varies with the site, histologic grade, depth, and size of the tumor. For high-risk tumors, adjuvant therapy should be considered. In high-risk extremity tumors, adjuvant radiation has been proven in randomized trials to improve local control. Limb-sparing surgery combined with adjuvant radiation achieves equivalent local control to amputation, with the same distant relapse-free survival. Due to anatomical constraints, tumors of the head and neck and retroperitoneum are typically excised with close margins, providing a rationale for adjuvant radiation; the available evidence suggests but does not prove a benefit. Large-scale trials of adjuvant imatinib for gastrointestinal stromal tumors are currently being conducted. For tumors of the extremity/trunk, head and neck, and retroperitoneum, biopsy prior to definitive resection is recommended to establish the diagnosis and permit intelligent treatment planning with appropriate choice and sequencing of adjuvant therapies. This planning is most expeditiously done through multidisciplinary consultation at an experienced sarcoma center.

Retroperitoneal and Visceral Sarcomas: Issues for the General Surgeon

Sarcomas represent a rare, heterogeneous group of malignant tumors that arise from the mesenchymal tissues of the body. Although infrequently encountered, these tumors generate vigorous academic interest and an ever-expanding volume of medical literature. Chemotherapy is widely regarded as ineffective because of the often-large tumor burden and lack of good therapeutic drugs. Radiation therapy is often difficult to administer because of locoregional toxicity. Fortunately, targeted immunologic therapies have shown promise in some specific gastrointestinal mesenchymal tumors. To date, sarcoma remains a malignancy best treated operatively. Given the wide heterogeneity and biology of these tumors and the amount of new data available, a review of the current literature is warranted. The first installment of this review series1 dealt with extremity and trunk soft tissue sarcomas; this one will focus on retroperitoneal and visceral sarcomas and the management challenges they pose.

Complications associated with neoadjuvant radiotherapy in the multidisciplinary treatment of retroperitoneal sarcomas

INTRODUCTION

Retroperitoneal sarcomas (RPS) remain a therapeutic challenge due to high local recurrence rates. Preoperative RT offers theoretical advantages in the multidisciplinary care of RPS. The purpose of our study was to evaluate our experience using preoperative radiotherapy (PRT) in the treatment of RPS.

METHODS

This is a single-institution review of patients with RPS treated with PRT from 1994 until 2004. Three radiation oncologists and four surgical oncologists were involved. Medical records, tumor registries, and death records were reviewed.

RESULTS

Fourteen patients were included; nine were treated for primary presentation and five for recurrent disease. Histologic grade was grade I (n = 3), grade II (n = 3), and grade III (n = 8). Five patients received additional IORT. Radiotherapy complications were generally mild, including nausea (n = 3), diarrhea (n = 1), dehydration (n = 1), anemia (n = 1), and skin changes (n = 1); one required early cessation due to nausea. Thirteen patients had gross negative margins; while 7/13 had negative microscopic margins. Operative complications included anastomotic bleeding (n = 1), fluid collections (n = 2), ileus (n = 3), ascites (n = 2), temporary leg weakness (n = 1), and uncomplicated wound infections (n = 2). In patients with R0 or R1 resections, one and two year local control rates were 64 and 50%. Overall survival for all patients was 90% at 1 year and 74% at 2 years with median survival of 21 months.

CONCLUSION

PRT and IORT can be administered effectively in carefully selected patients with resectable RPS. Larger multi-center studies are needed to delineate the role of PRT and IORT to improve local recurrence and survival rates in the treatment of RPS.

Retroperitoneal sarcomas: Combined-modality treatment approaches

Retroperitoneal sarcomas (RPS) are rare tumors, accounting for approximately 15% of soft tissue sarcomas. Surgical resection of localized tumors with gross and microscopically negative margins remains the standard of care. However, because RPS are frequently large and locally advanced, resections are often incomplete, resulting in local recurrence. Investigators are evaluating combined-modality therapies to improve local control and disease-specific survival. This review outlines current concepts and evolving treatment strategies in the diagnosis, staging, and management of RPS.

Primary and recurrent retroperitoneal soft tissue sarcoma: prognostic factors affecting survival

BACKGROUND AND OBJECTIVES

To analyze treatment and survival in 34 patients (28 resected) with primary or recurrent retroperitoneal sarcoma (RPS).

METHODS

Between July 1994 and January 2001, 34 patients (15M, 19F; mean age: 56 years, range: 25-77) were evaluated. Complete resection was defined as removal of gross tumor with histologically confirmed clear resection margins.

RESULTS

Twenty-eight out of 34 patients (82%) (15 were affected by primary RPS, and 13 by recurrent RPS), underwent surgical exploration. Twenty-three patients had a grossly and microscopically complete resection, (3 having a grossly incomplete resection and 2 patients with a grossly complete resection having histologically involved resection margins). Twenty-one out of 28 patients (75%) underwent removal of contiguous intra-abdominal organs. Preoperative mortality was nil, and morbidity occurred in six cases only (21%). High tumor grade results a significant variable for a worse survival in all 28 patients (100% 5 years survival for low grade vs. 0% for high grade; P = 0.0004). Amongst completely resected patients, only histologic grade and peroperative blood transfusions affected disease-free survival (P = 0.04 and P = 0.05, respectively).

CONCLUSIONS

An aggressive surgical approach in both primary and recurrent RPS is associated with long-term survival.

Targeted radiosensitisation by pegylated liposome-encapsulated 3', 5'-O-dipalmitoyl 5-iodo-2'-deoxyuridine in a head and neck cancer xenograft model

5-Iodo-2′-deoxyuridine (IUdR) is an effective radiosensitiser but its clinical development has been limited by toxicity. Prolonged intravenous infusions of IUdR are necessary for optimal tumour uptake but cause dose-limiting myelosuppression. The lack of selective tumour uptake can lead to radiosensitisation of adjacent normal tissues and enhanced local radiation toxicity. Liposomal IUdR delivery offers selective targeting of tumour tissues and avoidance of local and systemic toxicity. In these studies, we report the development of a pegylated liposome containing a lipophilic IUdR derivative (3′, 5′-O-dipalmitoyl-5-iodo-2′-deoxyuridine) for use in a head and neck cancer xenograft model. Initial studies confirmed the ability of IUdR to sensitise two head and neck cancer cell lines to single fractions of radiotherapy (SFRT) and this effect was seen to correlate with the thymidine replacement index in KB cells. In vivo delivery of single doses of either unencapsulated IUdR or pegylated liposomal IUdR (PLIUdR) to nude mice bearing KB xenograft tumours did not enhance the effect of SFRT delivered 16 h later. When PLIUdR was delivered by a protracted administration schedule to a dose of 48 mg kg⁻¹ over 7 days, it enhanced the effect of both 4.5 Gy SFRT and fractionated radiotherapy. PLIUdR was at least as effective as unencapsulated IUdR delivered by multiple intravenous injections or continuous subcutaneous infusion. Immunohistochemistry with a specific anti-IUdR monoclonal antibody confirmed greater levels of tumour staining in tumours from animals treated with PLIUdR compared with those treated with unencapsulated IUdR.

Primary malignant tumors of the iliopsoas compartment

BACKGROUND AND OBJECTIVES

Primary malignant tumors of the iliopsoas compartment are rare entities that have been infrequently reported. We present our experience of iliopsoas malignancy to better characterize and define the natural history of this condition.

METHODS

Primary iliopsoas tumors occurring from January 1990 were identified from the Royal Marsden Hospital's (RMH) Sarcoma Unit prospective database.

RESULTS

Nineteen malignant tumors (11 limited to the psoas muscle only, 1 involving only the iliacus muscle and 7 involving both the iliacus and psoas) of the iliopsoas compartment were evaluated and treated at the RMH during this period. Leiomyosarcoma (n = 5) and liposarcoma (n = 3) were the most frequent histologic types. There were 3 G1, 5 G2, 10 G3 tumors and grade could not be assessed in 1 patient. There were 17 T2 tumors and size was not available in 2 patients. Surgery was done in 14 patients (negative microscopic margins-7, positive microscopic margins-3, and positive gross margins-3 and the margin of excision was not known in 1 patient). Five of 14 surgically treated patients had local recurrence and 6 of 19 patients developed metastases. Ten patients died of their disease at a median follow-up of 12 months. The estimated 2 and 5 year survival rates were 44 and 23%, respectively.

CONCLUSIONS

Tumors in this location have a poor prognosis due to the lack of early diagnosis, large size at presentation, multiple attachments of the psoas muscle, and being relatively surgically inaccessible.

Treatment of intracranial rat glioma model with implant of radiosensitizer and biomodulator drug combined with external beam radiotherapy

PURPOSE

To evaluate an intracranial polymer implant containing bromodeoxyuridine (BrdUrd) and N-(phosphonacetyl)-L-aspartic acid (PALA) in combination with external beam radiotherapy (EBRT) in the treatment of a rat glioma.

METHODS AND MATERIALS

Combinations of the biomodulators 5-fluorouracil, methotrexate, or PALA with BrdUrd were evaluated as radiosensitizers in vitro by clonogenic assay. In in vivo experiments, BrdUrd and PALA were incorporated into a polyanhydride-based polymer, bis(p-carboxyphenoxy)propane sebacic acid, and implanted in the C6 rat glioma growing intracranially. The effectiveness of treatment was evaluated on the basis of survival. EBRT was given as 10-MV X-rays.

RESULTS

In tissue culture experiments, C6 cells were refractory to radiosensitization by BrdUrd even when the thymidine analog was combined with a biomodulator intended to reduce de novo thymidine synthesis. The most effective compound in vitro was PALA. When PALA and BrdUrd in a polymer formulation were implanted intracranially and combined with 10-Gy EBRT, the treatment was highly effective, with 83% of treated rats surviving 180 days.

CONCLUSION

Although the in vitro results were not encouraging, the combination of intratumoral BrdUrd and PAL with 10-Gy EBRT was highly effective in treating a rat glioma. These results indicate the clinical potential of combined and mixed modality treatments involving intratumoral sustained-release drug delivery.

Advances in neoadjuvant chemotherapy in soft tissue sarcomas

The use of adjuvant chemotherapy in soft tissue sarcomas (STS) continues to be an area of controversy; however, the group of investigators favoring the use of an anthracycline- and ifosfamide-based regimen for high-risk (American Joint Committee on Cancer stage III) extremity STS is steadily increasing. The historic 5-year survival rate of approximately 50% in this high-risk group treated with local therapy alone represents a poor standard of care, thus there is a need to incorporate systemic therapy early in the management of these patients. Published data from the meta-analysis of doxorubicin-based adjuvant chemotherapy trials and the prospective randomized data with epirubicin and ifosfamide from the Italian Sarcoma Group are frequently used as rationale for this approach. In a rare and heterogenous group of diseases, such as STS, physicians run into negative studies for various reasons that have little to do with the efficacy of the treatment being tested. The wisdom may be in capitalizing further on a positive lead as opposed to nihilism. It is appropriate to acknowledge that the chemotherapeutic agents have limited efficacy and are toxic, especially when used at full therapeutic doses. Selecting patients in whom there is some evidence of benefit, justifying the poor quality of life from receiving chemotherapy, becomes very important. This rationale, with the lessons learned from osteosarcoma research, forms the basis for neoadjuvant chemotherapy for STS. Until we reach the day when we have identified critical tumorigenic targets and their effective inhibitors for most of these tumors, we are obligated to use the available therapeutic armamentarium in the best possible sequence.

Retroperitoneal sarcomas: combined modality treatment approaches

Retroperitoneal soft tissue sarcomas are rare tumors estimated to account for 15%of all patients with soft tissue sarcoma seen in referral populations. The standard of care for patients with localized, resectable retroperitoneal sarcomas is surgical resection with gross and microscopically negative margins. However, owing to the large size and locally advanced nature of these tumors, this goal is difficult to achieve in most patients. As a result, the disease is characterized by a high propensity for local recurrence and a grade-specific risk for distant metastasis. Over the past decade, there has been considerable research into combined modality treatment of these tumors. The present report outlines current concepts relating to the diagnosis, staging, and management of retroperitoneal sarcomas. Emphasis is placed on evolving combined modality treatment approaches and current investigational strategies.

Preoperative chemoradiation treatment strategies for localized sarcoma

BACKGROUND

Over the past 2 decades, there has been increasing interest in chemoradiation treatment strategies for patients with soft tissue sarcomas. Investigators have evaluated: (1) the optimal route for chemotherapy administration (intra-arterial vs. intravenous); (2) the possible advantages of protracted infusion of the radiosensitizer versus brief infusion; (3) the efficacy and toxicity of various intravenous and oral radiation sensitizers; and (4) the efficacy of sequential versus concurrent combined modality treatment.

METHODS

The English-language literature addressing chemoradiation for localized and locally advanced extremity and retroperitoneal sarcomas was reviewed.

RESULTS

All studies have been pilot, phase I, or phase II designs. The most commonly used radiosensitizer for concurrent chemoradiation has been doxorubicin, administered intravenously in most recent reports. In the studies that have included assessment of recurrence-free survival, preoperative chemoradiation combined with surgery has resulted in favorable local control rates, often in excess of 90% for patients with localized and locally advanced extremity sarcomas.

CONCLUSIONS

The toxicities and recurrence-free outcome with chemoradiation plus surgery for soft tissue sarcoma still need to be compared to these with surgery and pre- or postoperative radiation. However, the generally favorable local control rates reported for chemoradiation justify continued investigation of preoperative chemoradiation strategies for localized sarcoma.

Five-chlorodeoxycytidine, a tumor-selective enzyme-driven radiosensitizer, effectively controls five advanced human tumors in nude mice

PURPOSE

The study's goals were as follows: (1) to extend our past findings with rodent tumors to human tumors in nude mice, (2) to determine if the drug protocol could be simplified so that only CldC and one modulator, tetrahydrouridine (H4U), would be sufficient to obtain efficacy, (3) to determine the levels of deoxycytidine kinase and dCMP deaminase in human tumors, compared to adjacent normal tissue, and (4) to determine the effect of CldC on normal tissue radiation damage to the cervical spinal cord of nude mice.

METHODS AND MATERIALS

The five human tumors used were as follows: prostate tumors, PC-3 and H-1579; glioblastoma, SF-295; breast tumor, GI-101; and lung tumor, H-165. The duration of treatment was 3-5 weeks, with drugs administered on Days 1-4 and radiation on Days 3-5 of each week. The biomodulators of CldC were N-(Phosphonacetyl)-L-aspartate (PALA), an inhibitor of aspartyl transcarbamoylase, 5-fluorodeoxycytidine (FdC), resulting in tumor-directed inhibition of thymidylate synthetase, and H4U, an inhibitor of cytidine deaminase. The total dose of focused irradiation of the tumors was usually 45 Gy in 12 fractions.

RESULTS

Marked radiosensitization was obtained with CldC and the three modulators. The average days in tumor regrowth delay for X-ray compared to drugs plus X-ray, respectively, were: PC-3 prostate, 42-97; H-1579 prostate, 29-115; glioblastoma, 5-51; breast, 50-80; lung, 32-123. Comparative studies with PC-3 and H-1579 using CldC coadministered with H4U, showed that both PALA and FdC are dispensable, and the protocol can be simplified with equal and possibly heightened efficacy. For example, PC-3 with X-ray and (1) no drugs, (2) CldC plus the three modulators, (3) a high dose of CldC, and (4) escalating doses of CldC resulted in 0/10, 3/9, 5/10, and 6/9 cures, respectively. The tumor regrowth delay data followed a similar pattern. After treating mice only 11/2 weeks with CldC + H4U, 92% of the PC-3 tumor cells were found to possess CldU in their DNA. The great majority of head-and-neck tumors from patient material had markedly higher levels of dC kinase and dCMP deaminase than found in adjacent normal tissue. Physiologic and histologic studies showed that CldC + H4U combined with X-ray, focused on the cervical spinal cord, did not result in damage to that tissue.

CONCLUSIONS

5-CldC coadministered with only H4U is an effective radiosensitizer of human tumors. Ninety-two percent of PC-3 tumor cells have been shown to take up ClUra derived from CldC in their DNA after only 11/2 weeks and 2 weeks of bolus i.p. injections. Enzymatic alterations that make tumors successful have been exploited for a therapeutic advantage. The great electronegativity, coupled with the relatively small Van der Waal radius of the Cl atom, may result in CldC's possessing the dual advantageous properties of FdC on one hand and BrdU and IdU on the other hand. These advantages include autoenhancing the incorporation of CldUTP into DNA by not only overrunning but also inhibiting the formation of competing TTP pools in tumors. A clinical trial is about to begin, with head-and-neck tumors as a first target of CldC radiosensitization.

Targeting DNA mismatch repair for radiosensitization

Postreplicational mismatch repair (MMR) proteins are capable of recognizing and processing not only single base-pair mismatches and insertion-deletion loops (IDLs) that occur during DNA replication, but also adducts in DNA resulting from treatment with cancer chemotherapy agents. These include widely varying types of DNA adducts resulting from methylating agents such as MNNG, MNU, temozolomide, and procarbazine; CpG crosslinks resulting from cisplatin and carboplatin; and S(6)-thioguanine and S(6)-methylthioguanine residues in DNA. Although MMR proteins can recognize both replicational errors and chemotherapy-induced adducts in DNA, the end results of this recognition are very different. Base-base mismatches and IDLs can be repaired by MMR, restoring genomic integrity, whereas MMR-mediated recognition and processing of chemotherapy-induced adducts in DNA results in apoptosis. After the loss of MMR, the inability of cells to recognize and correct single base-pair mismatches and insertion-deletion loops can lead to secondary mutations in proto-oncogenes and tumor-suppressor genes, thereby contributing to the development of cancer. In addition, the inability of MMR-deficient cells to recognize chemotherapy-induced adducts in DNA can result in a damage-tolerant phenotype that translates to clinically significant resistance by allowing for selection of MMR-deficient cancer cells. We have shown recently that these MMR-deficient, drug-resistant cells can be targeted for radiosensitization by the halogenated thymidine analogs iododeoxyuridine (IdUrd) and bromodeoxyuridine (BrdUrd). These thymidine (dThd) analogs become incorporated into DNA and form reactive uracil radicals after ionizing radiation (IR), increasing strand breaks. IdUrd and BrdUrd appear to be removed from DNA in MMR-proficient cells with limited toxicity or disruption of the cell cycle, while accumulating at much higher levels in MMR-deficient cells. As a result, it is possible to effectively increase the radiosensitization of MMR-deficient cells at levels of halogenated dThd analog that demonstrate limited toxicity to MMR-proficient cells. This indicates that a combined approach of IdUrd or BrdUrd with IR may be effective in killing MMR-deficient tumors in patients, which are resistant to many cancer chemotherapy agents commonly used in the clinic.

Significance and management of local recurrences and limited metastatic disease in the abdomen

The management of patients with synchronous or metachronous metastatic carcinoma, sarcoma, or melanoma in the abdomen requires a knowledge of the natural history of the disease and of the available treatment options. Patients with advanced malignant disease may be of marginal performance status yet may require large surgical procedures or combined modality therapy; the most challenging therapeutic decisions involve such patients. The authors highlight the role of surgery in selected patients with metastatic or recurrent malignancy as it is practiced at The University of Texas M. D. Anderson Cancer Center.

Chemoradiation treatment strategies for localized sarcoma: conventional and investigational approaches

Current chemoradiation treatment strategies have largely evolved out of the experience reported by Eilber and colleagues from the University of California, Los Angeles (UCLA). The favorable local control rates they reported using intra-arterial doxorubicin-based concurrent chemoradiation have been confirmed by several other groups with some groups reporting local control rates in excess of 95% with this approach. This has led to further studies designed to evaluate: 1) the optimal route for chemotherapy administration--intra-arterial vs. intravenous, 2) the possible advantage of protracted infusion of the radiosensitizer vs. brief infusion, 3) the efficacy of other intravenous and oral radiation sensitizers, and 4) the efficacy of sequential chemoradiation using multi-agent chemotherapy alternating with radiotherapy. The results of these investigations are reviewed as the basis for ongoing research evaluating chemoradiation strategies for the treatment of patients with localized sarcoma.

Prognostic factors in retroperitoneal sarcomas: ploidy of DNA as a predictor of clinical outcome

BACKGROUND AND OBJECTIVES

Radical surgery is the best mode of treatment of retroperitoneal sarcomas (RS); however, common recurrences are unpredictable.

METHODS

For the better understanding of outcomes and possibilities of treatment retrospective analysis of different factors, including DNA content, was performed based on 70 patients.

RESULTS

Leiomyosarcoma and liposarcoma were most common histologic types of classified sarcomas. Different kinds of resection were successfully performed in 51 patients (73%) and 35 of their available DNA specimens were analyzed. The actuarial 5- and 10-year survival rates in the resection group were 53% and 40%, respectively, with the median survival of 57 months. Patients with diploid resected tumors had a better 10-year survival rate (58%), than those patients with aneuploid tumors (25%,)--P<0.005. Those patients with low-grade sarcomas had a significantly longer survival than those with high-grade sarcomas (10-year survival rate: 44% compared to 29%). In the univariate analysis, adjuvant therapy, type of histology, type of surgery, location of tumor, and S-phase fraction had no influence on survival. In the multivariate analysis (Cox), only ploidy was an independent prognostic variable. Relative risk of death was over three times higher for aneuploid than for diploid tumors.

CONCLUSION

Tumor ploidy should be analyzed in every case of retroperitoneal sarcoma for better assessment of prognosis and possible indication for adjuvant therapy.

Preoperative idoxuridine and radiation for large soft tissue sarcomas: clinical results with five-year follow-up

BACKGROUND

Local control remains an important issue in the management of large soft tissue sarcomas. Radiation is the main adjuvant to surgery for local therapy of sarcomas, but it requires relatively high doses, hitherto considered prohibitive in areas such as the retroperitoneum. We developed a preoperative treatment approach to large soft tissue sarcomas that would deliver a high total dose of radiation administered in conjunction with the halogenated pyrimidine radiosensitizer idoxuridine (IdUrd).

METHODS

Thirty-seven patients with large sarcomas of the head and neck, mediastinum, retroperitoneum, or extremity received three or five cycles of sequential IdUrd infusion (1000-1600 mg/m2/d x 5 d) alternating weekly with twice daily radiation (125-150 cGy per dose) and were then evaluated for resection. The delivered preoperative radiation dose was up to 6250 to 7500 cGy.

RESULTS

Five patients (14%) had a partial response to preoperative therapy, and 28 of 37 patients underwent successful resection. There were no intra- or postoperative deaths. Local control was achieved in 19 of 28 resected patients, but in only 1 of 6 patients who remained unresectable despite therapy. With a median follow-up of 5.8 years, 28% of patients are alive with no evidence of disease, 17% are alive with disease, and 53% have died of their disease.

CONCLUSIONS

Using the dose and schedule we employed, resection of large soft tissue sarcomas was possible after high-dose radiation delivered in conjunction with IdUrd. Although local control was acceptable, the high rate of distant failure represents a limitation of any local approach to the treatment of large soft tissue sarcomas and suggests the need for integration of this approach with an effective systemic therapy.

Preclinical studies of chemotherapy and radiation therapy for pancreatic carcinoma

The use of radiation therapy combined with 5-fluorouracil (5-FU) in the treatment of pancreatic cancer has been well established. It has been hypothesized that any benefit from combined 5-FU and radiation has been due to radiosensitization. Improved therapy could result from a better understanding of the mechanism of radiosensitization and the development of compounds capable of providing better radiosensitization. This article reviews preclinical findings on the mechanism of cytotoxicity and radiosensitization for 5-FU, fluorodeoxyuridine, thymidine analogs, and gemcitabine (2',2'-difluorodeoxycytidine) and discusses the clinical implications of these findings.

Effect of irradiation on bromodeoxyuridine incorporation in human colon cancer xenografts

PURPOSE

Although we have characterized the incorporation of the thymidine analog bromodeoxyuridine (BrdUrd) into human colon cancer xenografts under a wide variety of conditions, little is known about the effect of radiation on subsequent incorporation. Because clinical protocols include, as one component, BrdUrd administration after radiation, it was important to confirm that irradiation did not prevent subsequent BrdUrd incorporation. Therefore, we studied the effect of irradiation on BrdUrd incorporation into HT29 human colon cancer xenografts.

METHODS AND MATERIALS

Two types of experiments were performed. In the first, the effect of radiation on subsequent incorporation was measured. Tumors received doses of 0, 2, 8, and 12 Gy, animals were infused with BrdUrd for 4 days, and incorporation was assessed at the end of the infusion. In the second, the effect of radiation on the elimination of BrdUrd from tumors was determined. Animals were infused with BrdUrd, tumors were irradiated with either 0 or 12 Gy, and tumor incorporation of BrdUrd was measured 1 and 3 days later.

RESULTS

Radiation affected neither the incorporation into nor the elimination of BrdUrd from human tumor xenografts.

CONCLUSIONS

These findings support the feasibility of clinical trials interdigitating BrdUrd infusion and radiation.