Retroperitoneal tumors: Review of diagnosis and management

Abstract

Retroperitoneal tumors are extremely rare tumors occurring in the retroperitoneum. Retroperitoneal tumors are divided into benign tumors and malignant tumors, including retroperitoneal sarcoma. Approximately 70-80% of primary retroperitoneal soft-tissue tumors are malignant; however, these only account for 0.1-0.2% of all malignancies. Retroperitoneal sarcoma is an orphan malignant disease with a low incidence. The information on benign retroperitoneal tumors is limited. The American Joint Committee on Cancer/TNM classification updated to the 8th edition in 2017. In 2010, three new drugs for soft tissue sarcoma were approved based on the results of phase III trials, but the histological subtypes of the patients enrolled in the trials of each drug differed. Recently, in addition to surgery for retroperitoneal sarcoma, the effectiveness of perioperative radiation therapy has become interesting. For malignant retroperitoneal tumors and retroperitoneal sarcoma, survival improvement and locoregional recurrence prevention can be undertaken by carrying out surgery to secure negative margins with wide and combined resection of some adjacent organs, and cooperation with a trained medical team comprising of radiologists, pathologists and medical oncologists in centralized hospitals. Some clinical trials aimed at further improving treatment results by adding preoperative chemotherapy and radiation therapy based on histological confirmation using a correct needle biopsy are in progress. In recent years, molecular profiling has been used to select eligible patients for chemotherapy. In the future, precision medicine with next-generation sequencing technology will be expected among the diverse and potential future treatments for retroperitoneal sarcoma. In this review, we summarized the current state of retroperitoneal tumors and retroperitoneal sarcoma.

Editorial Comment from Dr Matsumoto to Adult genitourinary sarcoma: The era of optional chemotherapeutic agents for soft tissue sarcoma

“…When urologists treat genitourinary STS, they sometimes face difficulties as a result of the lack of specific evidence on the optimal therapeutic approach. Therefore, they have to follow the general treatment recommendations for retroperitoneal STS 1,2 . It is a general theory that the highest cure rate of STS is achieved during primary surgery.…”

Editorial Comment from Dr Arai to Adult genitourinary sarcoma: The era of optional chemotherapeutic agents for soft tissue sarcoma

“…However, even with several drugs available in Japan, only a small fraction of advanced or metastatic genitourinary sarcoma patients show partial responses. Furthermore, adjuvant radiation therapy for tumors with a positive margin is controversial in terms of overall survival 5 . Therefore, novel therapeutic strategies, including combination therapies with immune checkpoint inhibitors or precision medicine with next‐generation sequencing technologies, are warranted.…”

“…Therefore, novel therapeutic strategies, including combination therapies with immune checkpoint inhibitors or precision medicine with next‐generation sequencing technologies, are warranted. Several ongoing clinical trials will assess the efficacies of these novel strategies 5 …”

Editorial Comment to Retroperitoneal tumors: Review of diagnosis and management

“…Approximately 70–80% of primary retroperitoneal tumors are malignant; most of these are soft tissue sarcomas (STSs). Nevertheless, retroperitoneal STS (retroperitoneal sarcoma [RPS]) only accounts for 0.1–0.2% of all malignancies 1 . RPS can present with diverse histological manifestations and thus various clinical behaviors.…”

“…In this review, Sassa summarized the epidemiology, diagnosis and treatment of retroperitoneal tumors, which will provide us with the guidance we need in clinical practice 1 . The distribution of histological types of sarcoma significantly differs according to the primary sites.…”