Published online Aug 27, 2019. doi: 10.4240/wjgs.v11.i8.334
Peer-review started: June 4, 2019
First decision: August 2, 2019
Revised: August 10, 2019
Accepted: August 13, 2019
Article in press: August 2, 2019
Published online: August 27, 2019
Processing time: 89 Days and 12.7 Hours
Anorectal leiomyosarcomas (LMSs) are rare and complex tumors, known to present a therapeutic dilemma and having a high tumor recurrence risk after resection. Prior to application of immunohistochemistry to their diagnosis, LMSs were often misdiagnosed as gastrointestinal stromal tumors, which have a different treatment approach and prognosis. Additionally, owing to the rarity of anorectal LMSs, they are usually reported collectively with LMSs in other locations of the gastrointestinal tract.
To conduct a recent and comprehensive review of anorectal LMS in the time following the advent of immunohistochemistry use to highlight the tumor characteristics, treatment approach, role of adjuvant chemoradiation, and tumor prognosis as well as to review postradiation LMS of the anorectum.
To conduct a recent and comprehensive review of anorectal LMS in the time following the advent of immunohistochemistry use to highlight the tumor characteristics, treatment approach, role of adjuvant chemoradiation, and tumor prognosis as well as to review postradiation LMS of the anorectum.
A systematic literature search of the PubMed electronic database was conducted using the MeSH terms “rectal neoplasms”, “anus neoplasms” and “gastrointestinal neoplasms” combined with “leiomyosarcoma”. The search was limited to English language and studies on humans. All available case reports and case series of anorectal LMSs that were published from January 1996 to May 2017 were included if the diagnosis of LMS had been confirmed by histopathologic examination.
We identified a total of 27 articles, reporting on 51 cases of anorectal LMS. Of these, 6 reported on cases of previous pelvic radiotherapy who had developed LMS 13-35 years after the radiation. Anorectal LMS affected the rectum in 92.2% of the cases, and no sex-based predominance was observed. Surgical resection with negative margins remains the mainstay of treatment, which can be accomplished by wide local excision or radical resection. The rate of local recurrence was higher in wide local excision (30%) compared to radical resection (20%), and the overall rate of metastasis was 51.61% regardless of the treatment approach. Use of neoadjuvant radiation lowers the risk of local recurrence, as compared to adjuvant radiotherapy, and facilitates R0 resection of the tumor. The use of adjuvant chemotherapy has shown improvement in distant recurrence and overall survival rates; however, multidisciplinary team discussion is necessary to determine the optimal management plan whilst considering patient and disease-related factors.
The mainstay treatment of anorectal LMS is surgical resection with negative margins. Sphincter-preserving surgery followed by radiotherapy showed comparable local recurrence rates to radical resection based on case series and reports. Neoadjuvant radiation improved local recurrence rates compared to adjuvant radiation. Adjuvant chemotherapy showed significant improvement in distant recurrence and overall survival rates; however, use of chemotherapy in this setting should be assessed by a multidisciplinary team and with consideration to patient-related factors and treatment toxicity. Nevertheless, local and distant tumor recurrence are common and may develop years after the resection. Therefore, long-term follow-up is needed after surgery.
Anorectal LMSs are rare tumors and further randomized controlled trials are needed to outline the criteria for patients’ eligibility for sphincter-preserving surgery compared to radical resection. A multidisciplinary team approach is necessary for optimal management.