Background: The anorectal leiomyosarcoma (LMS) is an aggressive malignant neoplasm. Owing to the rarity of LMSs, an optimal treatment modality has yet to be determined.
Aim: To collect all published data on anorectal LMS characteristics, explore current treatment options, and review recent cases of postradiation LMS.
Methods: A 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 human studies. All available case reports and case series of anal or rectal LMSs that were published from the beginning of January 1996 to May 2017 were included if the diagnosis of LMS had been confirmed by histopathologic examination. Data were analyzed using simple statistics (mean, median, and standard deviation). Independent sample t-test was used to compare means for continuous variables.
Results: A total of 27 articles reporting on 51 cases of anorectal LMS were identified. Among these cases, 11.7% had undergone previous pelvic radiotherapy (developing LMS at 13-35 years afterwards). 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 with wide local excision or radical resection. The local recurrence rate was higher among cases who received wide local excision (30%), as compared to radical resection (20%); however, the overall rate of metastasis was 51.61% regardless of the treatment approach. The use of neoadjuvant radiation lowers the risk of local recurrence compared to adjuvant radiotherapy, and facilitates R0 resection of the tumor. Cases treated with adjuvant chemotherapy showed better rates of distant recurrence and overall survival. Nonetheless, multidisciplinary team discussion is necessary to determine the optimal management plan whilst considering patient- and disease-related factors.
Conclusion: A multidisciplinary team approach, considering the underlying patient- and disease- related factors, is necessary for optimal management of these complex tumors.
Keywords: Anal neoplasms; Gastrointestinal neoplasms; Leiomyosarcoma; Rectal neoplasms; Soft tissue neoplasms.