A pilot study of extralevator abdominoperineal excision for primary melanoma of the anorectum

Implementation of robot-assisted curative resection for rare anorectal tumours on the basis of individualised treatment

PURPOSE

To evaluate the validity of robot-assisted curative operation for rare anorectal tumours, characterised by biological heterogeneity and anatomical complexity.

METHODS

The present study evaluated 16 consecutive patients including three with anorectal squamous cell carcinoma (ARSCC), four with anorectal mucosal melanoma (ARMM), seven with anorectal neuroendocrine tumour (ARNET), and two with other types of anorectal tumours.

RESULTS

Of the three patients with ARSCC after chemoradiotherapy, two underwent abdominoperineal resection (APR), and one underwent ultralow anterior resection (uLAR)/total intersphincteric resection (ISR), surviving 56-76 months without recurrence. Of the four ARMM patients, APR and uLAR/total ISR were conducted in two patients, respectively, with variable survival outcomes. All seven patients with ARNET were treated with uLAR/ISR and LAR, surviving for 5-106 months to date.

CONCLUSIONS

Because most anorectal tumours are confined to the dermal and submucosal layers, robotic anorectal function preserving ISR is expected to achieve R0 resection.

Primary anorectal malignant melanoma with laparoscopic abdominoperineal resection: a case study and review of the relevant literature

ARMM is a disease with a poor prognosis. ARMM is often diagnosed at an advanced stage, and the 5-year survival rate of ARMM is < 20%. Although the number of case reports on ARMM is gradually increasing, the optimal treatment strategy for ARMM remains controversial. We report the case of an 81-year-old woman who had experienced bloody stool for 6 months before her diagnosis and who had been initially diagnosed with hemorrhoids. The pathological diagnosis of a biopsy specimen was malignant melanoma. Other examinations showed no evidence of lymph node or distant metastasis. Based on these results, laparoscopic abdominoperineal resection was performed. Three months later on her first follow-up examination, distant metastasis to the lung and liver was detected. Immunotherapy using Nivolumab was initiated to treat the recurrent disease. We reviewed the characteristics of a total of 1834 ARMM patients described in previous reports on ARMM for which the full text was available on PubMed. We experienced a case of ARMM. The prognosis of ARMM is still poor, regardless of the surgical procedure. Previous studies and our case report suggest that systemic therapy, such as immunotherapy using an anti-PD-1 ligand may be more important than reinforcement of local control for improving the prognosis of ARMM patients.

Anorectal malignant melanoma: curative abdominoperineal resection: patient selection with 18F-FDG-PET/CT

Background

Anorectal malignant melanomas (ARMM) are rare tumors, characterized by an early lymphatic spread and distant metastasis, resulting in an extremely poor overall survival. The objective of this study was to determine the pattern of regional lymph node metastasis (LNM) by computed tomography (CT) and 18F-FDG-PET/CT in patients undergoing abdominoperineal resection (APR) and its impact on oncologic outcome.

Methods

A retrospective analysis of six consecutive patients who underwent APR due to primary ARMM was performed. Patients were staged by CT and PET/CT.

Results

Four out of six patients had preoperative LNM involvement (two patients inguinal and perirectal, one iliacal, one perirectal), with two of them presenting with distant metastases additionally. Inguinal/iliacal LNM in two patients as well as liver metastasis in one patient was seen in PET/CT and missed by CT. The three patients with initial inguinal/iliacal LNM died during the observation period (overall survival: 10 (6–18) months). The three patients without inguinal/iliacal LNM involvement are currently alive, one patient showing a slowly progressive disease since 5 years, and two patients are tumor-free since 8.5 and 1.5 years (the patients had initial perirectal LNM).

Conclusions

In ARMM, PET/CT is superior to CT in detection of LNM and distant metastasis. APR is possibly a curative approach if the PET/CT shows exclusively perirectal LNM despite locally advanced tumor growth.