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Local Excision for Rectal Cancer: An Uncertain Future

Local Excision for Rectal Cancer: An Uncertain Future

ABSTRACT: Adenocarcinoma of the rectum remains a significant public health challenge, with 39,000 new cases and 8,500 deaths predicted for 1998. Radical surgery, the current standard therapy, frequently necessitates the formation of a permanent colostomy and is associated with significant morbidity. For these reasons, alternatives to radical surgery have been sought. This review focuses on sphincter-sparing surgical modalities for distal rectal cancer. An extensive review of the literature on local excision alone, local excision plus postoperative radiation therapy (with or without chemotherapy), and local excision following preoperative chemoradiotherapy is presented. The design and interim results of the sole prospective multi-institution trial of local excision, Cancer and Leukemia Group B trial 8984, are also summarized. The literature on this subject, which is dominated by single-institution, retrospective reports, fails to support local excis-ion as a superior or equal therapy to radical surgical excision for invasive distal rectal adenocarcinoma. The crucial question regarding the efficacy of radical surgical salvage for local recurrence following local excision also remains unanswered. We conclude that the role of local excision for invasive distal rectal adenocarcinoma remains undefined. If there is a future for this therapeutic modality, it will depend significantly on rigorous patient selection, provided that the efficacy of radical surgical salvage for local recurrence can be established.[ONCOLOGY 12(6):933-947, 1998]

Adenocarcinoma of the rectum remains a significant public health
challenge, with 39,000 new cases predicted for 1998 resulting in an
estimated 8,500 deaths.[1] The current standard therapy for invasive
adenocarcinoma of the rectum is radical en bloc resection with
negative surgical and histologic margins. Lesions of the mid- and
proximal rectum may, in most instances, be treated with low anterior
resection, with appropriate distal margins and preservation of
sphincter function.

In contrast, lesions of the distal rectum often do not allow the
surgeon and patient the option of a sphincter-preserving procedure,
as the requirement for an adequate distal margin mandates an
abdominoperineal resection. This therapeutic approach necessitates
formation of a permanent colostomy, which is associated with
compromised quality of life for a significant percentage of
patients.[2] Abdominoperineal resection is also associated with
significant morbidity, which includes urinary dysfunction in 10% to
70% (average 30%) of patients[3] and male sexual dysfunction;
specifically, impotence and retrograde ejaculation occur in 15% to
100% and 3% to 39% of patients, respectively.[3-7] The mortality of
abdominoperineal resection ranges from 1% to 5%[8-12] and has been
reported to be significantly increased in patients over 70 years of age.

For these reasons, alternatives to abdominoperineal resection, both
surgical and nonsurgical, have been sought. Nonsurgical modalities
include endocavitary radiation, an approach extensively utilized by
Papillon, who reported a 5-year survival rate of 72% and a local
recurrence rate of 7% in selected patients so treated.[13-15]
Electrofulguration has also been utilized for both palliation of
advanced-stage disease and cure of early-stage lesions in patients
judged to be at prohibitive risk of complications and death from
radical surgery. Multiple authors have reported survival rates of 52%
to 68% in patients followed for a minimum of 4 years after
electrofulguration therapy.[16-19] Laser therapy is employed as a
palliative modality to maintain rectal lumen patency, sparing
high-risk, advanced-disease patients the need for colostomy
diversion.[20,21] Nonsurgical therapeutic approaches to rectal cancer
do not allow for pathologic and histologic evaluation of a completely
resected specimen and, therefore, provide limited staging information.

This article will focus on sphincter-sparing surgical modalities for
distal rectal cancer. An extensive review of the literature
pertaining to local excision alone, local excision plus postoperative
radiation therapy (with or without chemotherapy), and local excision
following preoperative chemoradiotherapy will be presented. The
literature on this subject is dominated by single-institution,
retrospective reports. However, we feel that this represents a
valuable collective experience worthy of review. These reports
provide a foundation on which future multicenter, prospective trials
designed to clarify the role of sphincter-preserving surgery for
invasive distal rectal cancer can be based. The design and
preliminary results from the sole multi-institution prospective trial
of local excision and postoperative chemoradiotherapy, Cancer and
Leukemia Group B (CALGB) trial 8984, will also be reviewed.[22] These
collective results indicate that the optimal strategies for local
excision and sphincter-preserving therapy require further study.

Additional topics discussed in this review include assessment of risk
of lymph node metastases, the role of salvage radical surgery
following local recurrence, and quality of life following local
excision for invasive distal rectal cancer.

Abdominoperineal Resection for Early-Stage Disease

Local excision for invasive distal rectal adenocarcinoma was
initially utilized in patients considered too ill to undergo
abdominoperineal resection. Follow-up of these patients indicated
that they did not sustain inordinately high rates of local recurrence
or death from metastatic disease when compared to historical outcome
data for abdominoperineal resection.[13,23-28]

Attempts to apply local excision-based therapy to rectal cancer in
patients who are candidates for radical surgery demand that
the results be compared to those of current standard therapy.
Although the morbidity and quality-of-life issues associated with
abdominoperineal resection and, to a lesser extent, low anterior
resection are significant, these procedures remain the standard of
care. The criteria by which the treatment of rectal adenocarcinoma
must be judged remains the frequency of local disease recurrence,
disease-free survival, and overall survival.

Several recent series review these parameters in patients treated for
early-stage invasive rectal adenocarcinoma with either
abdominoperineal resection or low anterior resection. The Dukes’
staging system, Astler-Coller modification of the Dukes’ system,
and the TNM staging system are all represented in the articles
discussed in this review. In order to assist the reader, each of
these staging systems is outlined in Table
1
.

Sticca et al (Table 2) reviewed the
recurrence patterns and outcomes of 71 patients with stage I rectal
adenocarcinoma treated with radical resection at a single
institution.[29] Of the 71 patients, 20 had T1 N0 M0 cancers and 51
had T2 N0 M0 cancers. The median follow-up for all patients was 81
months. The median number of lymph nodes examined per specimen was 32.

There were no recurrences in the 20 patients with T1 lesions. All
seven recurrences (10%) occurred in patients with T2 lesions. Two of
the recurrences were local only. Four patients recurred with distant
disease, and one recurred with local and distant disease during follow-up.

In the T2 group, the 5- and 10- year disease-free survival rates were
88% and 83%, respectively. Of interest is the fact that the T1 group
included one patient with lymphatic and/or vascular invasion and the
T2 group included four such patients. Only one of the five patients
with these histologic characteristics suffered a recurrence. This
observation will be reconsidered later in this review, when the
factors associated with recurrent disease following local excision
are discussed.

Wilson and Beahrs[30] assessed 5- and 10-year survival in 556
patients with mid- and proximal rectal cancers treated with low
anterior resection, and reported 89% and 86% rates of 5-year survival
for patients with Dukes’ A (T1), and Dukes’ B1 (T2)
lesions, respectively (Table 2).
Grigg et al[31] reported on 268 patients with carcinoma of the rectum
confined to the submucosa (T1) treated with either abdominoperineal
resection or low anterior resection; the 5-year cancer specific
survival rate in these patients was 88% (Table
2
).

McDermott et al[32] studied 276 patients with Dukes’ stage A
lesions of the distal rectum treated with abdominoperineal resection;
the local recurrence rate in these patients was 10% (Table
2
). In the series of McDermott et al, local recurrence doubled
in patients with poorly differentiated lesions, as compared with
patients with moderate- or well-differentiated lesions. Median
survival was 35 months following local recurrence alone and 39 months
following distant recurrence. Overall survival was not reported.

Willet et al[33] evaluated patients with stage I rectal cancer
treated with abdominoperineal resection. They reported no treatment
failures among 12 patients with T1 lesions, whereas 8 (15%) of 52
patients with T2 lesions did develop a recurrence. Risk factors
associated with recurrent disease, in addition to muscularis propria
invasion (T2 lesions), included vascular/lymph vessel involvement and
the presence of extensive stromal fibrosis on histologic evaluation.

In a review of a 25-year experience at St. Marks Hospital, London,
Dukes and Bussey[34] reported outcome results for 3,596 rectal cancer
patients (Table 2). The corrected
cancer-specific 5-year survival rate for Dukes’ A and B lesions
(T1-3 N0) was 82.5%. The corrected 5-year survival rate for lesions
confined to the bowel wall, Dukes’ A (T1-2), was 97.7%. The
percentage of lymphatic metastases was 14.2% in patients whose cancer
was confined to the bowel wall (T1-T2). Among patients with
"slight spread" (ie, minimal invasion into extrarectal
tissues; T3), the percentage of patients with positive lymph nodes
was 43.2%, based on an evaluation of 516 cases.

Taken as a group (Table 2), the
5-year survival rates for T1 lesions from the two larger series that
included poorly differentiated cancers[30,31] are comparable, at 89%
and 88%, respectively. None of the 20 patients with T1 tumors in the
series of Sticca et al, all of whom were alive at 5 years, had poorly
differentiated lesions.[29] The observations of McDermott et al[32]
and Wilson et al[30] of a 10% local recurrence rate and a 6%
anastomotic recurrence rate, respectively, should be kept in mind as
we review the sphincter-preserving surgical modalities, with and
without various adjuvant treatment modalities, for invasive
adenocarcinoma of the rectum.

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