This paper consists of a review of the literature on carcinoma
of the anal margin, as well as the authors' institutional experience
with this uncommon malignancy. The authors offer recommendations
for treatment based on the size of the tumor, which correlates
with the T-stage from the TNM or Union Internationale Contre le
Cancer (UICC) staging systems. They recommend radiation alone
or local excision for T1 lesions, radiation and elective nodal
irradiation for T2 lesions, and chemoradiation, including irradiation
of the primary tumor and inguinal and pelvic nodes, for T3 and
The authors' series from the University of Florida at Gainesville
(1979-1993) consists of eight patients with T2, N0, M0 disease
and two patients with T3, N0, M0 disease who were treated with
50 to 69 Gy of radiation, including elective inguinal irradiation.
Treatment was accomplished without "severe" complications
or compromise of anal function, and there have been no local,
inguinal, or distant recurrences with a minimum follow-up of 2
years. The authors also review the literature, as scanty as it
is, on staging and natural history, surgical treatment, radiation
therapy, and adjuvant chemotherapy.
Important Points Highlighted
The authors highlight several important points about this cancer.
Anal margin cancers are defined as those occurring between the
dentate line and the hair-bearing perianal skin. Most clinicians
agree that the anal canal extends from the anorectal ring to the
anal verge. Many tumors occurring in the anal canal straddle the
dentate line. In fact, most tumors occurring in the surgical anal
canal are treated much the same as "true" anal cancers.
There are two reasons for this: (1) the overwhelming success of
chemoradiation therapy in achieving local control of anal squamous
cell cancer with preservation of anal function and a reduction
in the need for permanent colostomy, and (2) the difficulty of
attaining successful healing and adequate function after excision
of lesions in the anal canal.
When T1 ( 2 cm or less) or even some T2 (2 to 5 cm) squamous cell
cancers lie outside the surgical anal canal, excision alone can
be successful because of the low incidence of nodal spread. Although
such excisions can be technically demanding in terms of wound
closure, functional and oncologic results are excellent. Abdominoperineal
resection (APR) usually is not needed to treat these cancers.
I would agree with the authors that in cases of T3 or T4 tumors
or tumors encompassing more than 50% of the anal verge or anal
canal, chemoradiation, including elective inguinal nodal irradiation,
is indicated. In light of the authors' ability to deliver treatment
to the primary tumor and inguinal nodes with such low morbidity
and overall effectiveness, one cannot argue with their approach
of treating T2 or more extensive tumors with radiotherapy.
Although the authors present a series with virtually a 100% rate
of optimal outcomes, other series that they cite, as well as more
recently published series, demonstrate both treatment failures
and morbidity with radiotherapy. For example, in a series of 17
patients treated with radiation, Touboul and others found a 40%
cancer-related death rate at 5 years for patients with T2 tumors,
and severe anal function complications occurred in 2 patients,
albeit at radiation doses of 60 to 70 Gy.
Thus, for those who advise and treat patients with anal margin
cancers, two challenges remain: (1) the identification of patients
in whom conservative treatment is likely to fail, and (2) the
delivery of effective treatment with minimal morbidity and preservation
of quality of life. The authors are to be commended for their
achievement of these goals in their series of patients with T1-2,
N0, M0 anal margin cancer.
1. Touboul E, Schlienger M, Buffat L, et al: Epidermoid carcinoma
of the anal margin: 17 Cases treated with curative-intent radiation
therapy. Radiother Oncol (Ireland) 34(3):195-202, 1995.