The surgical management of anorectal malignant melanoma

Wide local excision or abdominoperineal resection as the initial treatment for anorectal melanoma?

BACKGROUND

Anorectal melanoma (AM) is a rare tumor with a poor prognosis. Treatment with abdominoperineal resection (APR) over wide local excision (WLE) is still debated. This study aimed to compare median survival of WLE and APR in patients with AM.

METHODS

A systematic review of the literature was performed. Only series that allowed calculation of median survival were included.

RESULTS

Fourteen studies met inclusion criteria. Average median survival of stage I WLE patients (N=34) and stage I APR patients (N=31) was 44 and 22 months, respectively (P=.001). For stage II patients, 7 underwent WLE, and 10 underwent APR with an average median survival of 36 and 14 months, respectively (P=.19).

CONCLUSIONS

This study identified no stage-specific survival advantage to APR in favor of AM. Given that WLE is a more limited intervention associated with at least comparable survival, we propose that it be considered the initial treatment of choice for AM.

Where the sun never shines: anorectal melanoma

BACKGROUND

Melanoma occurring in the anorectal region is recognized to be an uncommon tumour with a poor prognosis. Queensland has the highest incidence rate of cutaneous melanoma in the world. The purpose of the present study was to determine if the very high incidence of cutaneous melanoma in Queensland has any bearing on the incidence of anorectal melanoma, and to compare this with published studies from other parts of the world. An assessment of the authors' results in the treatment of anorectal melanoma was made by a review of patients presenting during the last decade throughout Queensland.

METHODS

All cases of melanoma occurring in Queensland are accumulated in the Melanoma Register, administered by the Queensland Melanoma Project, and data from this were used to derive the results in the present study. Queensland population data were provided by the Australian Bureau of Statistics.

RESULTS

During the study period 1985-95 in Queensland there were 21,391 cases of cutaneous melanoma which occurred in an average population, during that time, of 2.89 million. During the same time there were nine cases of anorectal melanoma, giving a relative incidence therefore of 0.04%. This contrasts with published relative incidences of 0.2% for white people in North America, 11% for Southwestern Native Americans, and 14.2% for Northern Pakistan (P < 0.0001). However, the population-based incidence rates of anorectal melanoma for Queensland, United States white people, Southwestern Native Americans and Northern Pakistan are not significantly different from each other. All patients in the present series presented with large tumours, and none survived beyond 25 months despite standard surgical and adjuvant therapy.

CONCLUSIONS

The protection against cutaneous melanoma afforded by skin pigmentation is not apparent in the anal area. Anorectal melanoma is no more or less frequent in Queensland, even with the very high incidence rate of cutaneous melanoma. Sun exposure appears to be neither protective nor a risk factor. The outcome of therapy for this condition remains disappointing in the authors' experience.

Malignant melanoma of the anorectal region

The charts of 15 patients with malignant melanoma of the anorectal region treated at Roswell Park Cancer Institute in the period 1975-1991 were reviewed. All the lesions except one developed at the pectinate line, in the area of transitional mucosa. Two of the patients at the time of initial presentation had distant metastases. Of the remaining 13, 8 were treated with abdominoperineal resection (APR) and 5 with local excision (LE). The incidence of local recurrence was 50% in the LE group and 22% in the APR group. Patients treated with APR had a 25%, 5-year survival rate compared with 0% for those treated with LE, although one of the latter group died 55 months following LE due to unrelated causes without recurrence. The median survival of those with LE was 15.7 months and of those with APR 13.7 months.

Anorectal melanoma

Four cases of anorectal melanoma are presented. The authors believe that this is the first report of the occurrence of this tumour in Malays. Advanced disease at initial presentation accounts for the poor prognosis observed in this series. Surgery remains the principal treatment modality, although controversy exists regarding optimal extent of resection.

Surgical treatment of anorectal melanomas

Thirty cases of anorectal melanoma have been recorded in Israel from 1960 to 1981. The frequency of the disease doubled in the last decade (from 10 to 20 cases). A clear predominance has been noted among Jews of European descent (18 patients) as opposed to Sephardic Jews (9 patients) or Arabs (3 patients). From this series, the emerging conclusion is that in most cases radical surgery (abdominoperineal resection) is seldom indicated. It is doubtful whether this form of treatment increases the survival while affecting considerably the quality of life. Survival correlated well with the stage of disease at the time of diagnosis. No such correlation could be established with the type of treatment employed.