In their article, Drs. Wagman and
Minsky provide an excellent overview of the current status of local treatment strategies for early rectal
cancer. They have rightly pointed out that while minimal surgery is an
attractive option, it must be balanced against the highly curable outcomes of
radical surgical resection. Expanded experience with stapling devices has
extended the level at which safe and satisfactory anastomoses can be
accomplished in the distal rectum. The promise of enhanced preservation of
rectal, urinary, and sexual functions makes local treatment strategies an
attractive option. The most important aspect of disease management using this
approach remains the process of patient selection.
Importance of Patient Selection
Less than 10% of all patients with rectal cancer present with T1
or T2 disease. Even in this small subgroup, a variety of factors, such as tumor
size, stage, location, and patient habitus, often determine suitability for
local treatment. Conservative surgery should only be considered if the
probability of cure with surgery alone is high. Postoperative adjuvant therapy
should be an option reserved for findings of unfavorable histopathologic
features and should not be used as salvage therapy for inadequate surgical
resections. This would limit local excisions to T1 and "early" T2
cancers (ie, those with minimal infiltration of the muscularis propria).
The greatest value of transrectal ultrasound and magnetic
resonance imaging is in staging these early lesions. The results of the Cancer
and Leukemia Group B trial of local excision are cause for concern, in that 51
(almost 32%) of 161 patients were found to have more extensive T3 tumors or
positive surgical margins.. It remains unclear how an unsatisfactory local
excision in these patients may have compromised the subsequent outcome. These
patients not only run the risk of tumors seeding the perirectal space, but they
may have also lost the opportunity for radical sphincter-preservation surgery.
Challenges of Rectal Tumors
The location of the tumor in the rectum can present unique
surgical challenges. In men with an enlarged prostate, tumors of the anterior
rectal wall can pose a difficult technical problem. Similarly, in women, the
proximity of the vaginal wall can compromise adequate deep margins for
resection. Lesion size can also create a substantial challenge. Although the
standard recommendation for excision specifies tumors ≤ 3 cm or those occupying
less than 40% of the rectal wall’s circumference, a more important
consideration is the ability of the surgeon to effect an en bloc excision with a
"healthy" circumference and deep margins. Drs. Wagman and Minsky
appropriately emphasize the unfavorable outcomes in patients with positive
surgical margins and in patients undergoing piecemeal excision of their tumors.
There is considerable controversy, however, as to what
constitutes an adequate margin. Different authors have considered margins of 1-,
2-, or 3-mm cancer-free zones as adequate. Others have held that a
"healthy" margin is satisfactory. Clearly, there is a need to develop
greater precision in defining a suitable margin for cure by local excision.
Normal considerations of 1-cm margins around grossly visible tumors may not be
practical, especially with larger lesions, although it is often the larger
lesions that require the most generous margins. It is, therefore, imperative
that standardization and uniform reporting be developed for this technique.
A particular concern arises with the endoscopic removal of large
villous adenomas that are found to harbor invasive cancers upon histologic
examination. This situation should not be considered in the category of local
excision. Many of these adenomas are removed piecemeal and may not have a
full-thickness removal. It is our experience that these tumors fare poorly
because the adenomatous components can implant and grow in a surgical wound and
perirectal spaces. These cells are particularly resistant to ionizing radiation,
and many local recurrences that occur after local excisions are remnants of
adenomatous tissue that have been misconstrued as recurrent invasive cancers.
They are considered invasive because of their location in deep tissue planes.
It is also interesting to note that the presence of lymph node
metastasis is often the rationale for considering adjuvant therapy. However, as
pointed out by Drs. Wagman and Minsky, recurrences following local excision in
T1 and T2 cancers are invariably local, occurring at the site of resection in
the rectal wall.
In extensive experience with endocavitary irradiation without
pelvic irradiation, excellent local control was obtained with few regional nodal
failures. This raises the question of whether higher doses of radiation to more
limited volumes may prove to be more advantageous than conventional doses (45 to
50 Gy) to large pelvic volumes.
At the present time, long-term data are still insufficient to
assess the results of postoperative pelvic radiation on bowel, bladder, and
sexual functions following local excision. While significant stool clustering
and urgency are common after radical resection and postoperative radiation,
these problems seem to occur less frequently following local excision. Vaginal
dryness and dyspareunia in women and loss of sexual abilities in men are
potential side effects following treatment of other pelvic malignancies.
Preoperative Adjuvant Therapy
While our experience, as pointed out by Drs. Wagman and Minsky,
indicates an exceedingly favorable outcome with preoperative radiation and local
excision, there are only a few similar reports in the literature.The
expanding use of preoperative chemoradiation for the treatment of rectal cancer
has created new opportunities for extending the scope of conservative surgery to
patients with more advanced disease.
Several reports indicate significant downstaging of tumor (by
70% to 80%), with pathologic complete responses of 20% to 30%even in patients
with advanced rectal cancers.[3-5] These results are likely to be better for
early-stage and smaller-sized lesions. One effect of tumor downstaging is the
uncertainty of defining the tumor-bearing area for local excision. Prior to the
treatment, it is imperative that the tumor margins be tattooed by India ink so
that resection with appropriate margins can be undertaken with confidence. The
question of what constitutes adequate margins with preoperative treatment
remains to be determined, as does the question of whether resection should
include the pretreatment tumor-bearing area or the posttreatment residual tumor
In our experience with preoperative radiation, minimal resection
margins of 1 to 2 mm appear to be adequate. The major attraction of this
approach is the potential application of conservative treatment for T3 rectal
cancers. Our data strongly suggest that tumors downstaged to T0-T2 lead to
excellent local control and survival. However, patients who have persistent
postradiation T3 disease require radical surgical resection.
While there are no ongoing randomized studies in the United
States to evaluate this approach, an Italian surgical group is currently
undertaking a study comparing preoperative chemoradiation followed by transanal
endoscopic local excision using microsurgery and radical surgical resection with
total mesorectal excision. The results of this study should provide useful data
(personal communication, E. Lezche, 1999).
Enthusiasm for intracavitary irradiation of rectal cancer has
waned over the past decade. However, several large series reported by Papillon
and others indicate excellent local control rates of 76% to 93%.[5,6] Results of
this technique are especially favorable for tumors of the anterior rectal wall,
which may be the most technically difficult site for local excision.
Furthermore, endocavitary irradiation has not been extensively studied in
combination with preoperative chemoradiation, which together represent another
potential option for conservative treatment of early rectal cancer.
In summary, elective, conservative management of invasive rectal
cancer is an exciting new strategy that requires a great deal of discernment,
clinical judgment, and technical expertise.
1. Steele GD, Herndon JE, Bleday R, et al: Sphincter-sparing
treatment for distal rectal adenocarcinoma. Ann Surg Oncol 6(5):433-441, 1999.
2. Masoni L, Marks G, Petruzziello L, et al: Results of the
local excision of rectal cancer after high-dose radiotherapy associated or not
to chemotherapy. G Chir 18(10):622-629, 1997.
3. Mohiuddin M, Hayne M, Regine WF, et al: Prognostic
significance of postchemoradiation stage following preoperative chemotherapy and
radiation for advanced/recurrent rectal cancers. Int J Radiat Oncol Biol Phys
4. Janjan N, Khoo V, Abbruzzese J, et al: Tumor downstaging and
sphincter preservation with preoperative chemoradiation in locally advanced
rectal cancer: The M. D. Anderson Cancer Center Experience. Int J Radiat Oncol
Biol Phys 44:(5)1027-1038, 1999.
5. Valentini V, Coco C, Cellini N, et al: Preoperative
chemoradiation for extraperiotoneal T3 rectal cancer: Acute toxicity, tumor
response, and sphincter preservation. Int J Radiat Oncol Biol Phys 40:1067-1075,
6. Papillon J, Berard P: Endocavitary irradiation in the
conservative treatment of adenocarcinoma of the low rectum. World J Surg
7. Maingon P, Guerif S, Darsouni R, et al: Conservative
management of rectal adenocarcinoma by radiotherapy. Int J Radiat Oncol Biol
Phys 40(5):1077-1085, 1998.