Role of pre-operative irradiation for anal preservation in cancer of the low rectum

Non-operative management of rectal cancer: understanding tumor biology

The management of locally-advanced rectal cancer involves a combination of chemotherapy, chemoradiation, and surgical resection to provide excellent local tumor control and overall survival. However, aspects of this multimodality approach are associated with significant morbidity and long-term sequelae. In addition, there is growing evidence that patients with a clinical complete response to chemotherapy and chemoradiation treatments may be safely offered initial non-operative management in a rigorous surveillance program. Weighed against the morbidity and significant sequelae of rectal resection, recognizing how to best optimize non-operative strategies without compromising oncologic outcomes is critical to our understanding and treatment of this disease.

Accuracy of transrectal ultrasound after preoperative radiochemotherapy compared to computed tomography and magnetic resonance in locally advanced rectal cancer

INTRODUCTION

The aim of the present study was to compare the restaging results obtained by transrectal ultrasound (TRUS), computed tomography (CT), and magnetic resonance imaging (MRI) performed after preoperative chemoradiation with pathologic staging of the operative specimen.

METHODS

From January 2008 to December 2009, all the consecutive patients with locally advanced rectal cancer that underwent neoadjuvant therapy at our department were evaluated. The results of diagnostic examinations and the definitive pathological examination were considered and compared.

RESULTS

Thirty-seven patients were included in the study (27 males, 73%), mean age was 65.5 years (range 45–82 years). In all the patients TRUS and CT and in 20 patients MRI were performed before and after the treatment. Concerning the depth of invasion after treatment TRUS agreed with histopathology in 25/37 patients (67.5%), CT agreed in 22/ 37 cases (59.5%), and MRI in 12/20 cases (60%). Considering only neoplasia with stage T3, TRUS agreed in 23/24 cases (96%), CT in 19 cases (79%), and MRI in 10/12 cases (83.5%). Considering the tumors that did not exceed the rectal wall (T0, T1, and T2), TRUS agreed with histology in 2/13 cases (15.5%),CTin 3/13 cases (23%), andMRI 2/8 cases (25%). Concerning the presence of positive lymph nodes TRUS agreed with histology in 28/37 cases (75.5%), while CT agreed in 21/37 cases (56.5%) and MRI in 11/20 cases (55%). The concordance between the techniques was found to be low.

CONCLUSIONS

Transrectal ultrasonography resulted as the most accurate method to determine neoplastic wall infiltration and lymph node involvement even after radiochemotherapy. In most cases, considering the poor correlation between the diagnostic procedures and the disagreement of the results, a restaging performed only with TRUS could be proposed, limiting the use of the other imaging methods to selected cases.

Non-operative treatment after neoadjuvant chemoradiotherapy for rectal cancer

The past decade has seen pronounced changes in the treatment of locally advanced rectal cancer. Historically, the standard of care involved surgery followed by adjuvant radiotherapy or chemoradiotherapy. More recently, the emergence of neo-adjuvant chemoradiotherapy has fundamentally changed the management of patients with locally advanced disease. In clinical trials, pathological complete responses of up to 25% have raised the question as to whether surgery can be avoided in a select cohort of patients. A trial of omission of surgery for selected patients with complete response after preoperative chemoradiotherapy has shown favourable long-term results. In this article, we outline emerging factors for achieving pathological complete response, non-operative strategies to date, methods for prediction of response to chemoradiotherapy, and future directions with the addition of MRI as a radiological guide to complete response.

Preoperative therapy for lower rectal cancer and modifications in distance from anal sphincter

PURPOSE

To assess the frequency and magnitude of changes in lower rectal cancer resulting from preoperative therapy and its impact on sphincter-saving surgery. Preoperative therapy can increase the rate of preserving surgery by shrinking the tumor and enhancing its distance from the anal sphincter. However, reliable data concerning these modifications are not yet available in published reports.

METHODS AND MATERIALS

A total of 98 cases of locally advanced cancer of the lower rectum (90 Stage uT3-T4N0-N+ and 8 uT2N+M0) that had undergone preoperative therapy were studied by endorectal ultrasonography. The maximal size of the tumor and its distance from the anal sphincter were measured in millimeters before and after preoperative therapy. Surgery was performed 6-8 weeks after therapy, and the histopathologic margins were compared with the endorectal ultrasound data.

RESULTS

Of the 90 cases, 82.5% showed tumor downsizing, varying from one-third to two-thirds or more of the original tumor mass. The distance between the tumor and the anal sphincter increased in 60.2% of cases. The median increase was 0.73 cm (range, 0.2-2.5). Downsizing was not always associated with an increase in distance. Preserving surgery was performed in 60.6% of cases. It was possible in nearly 30% of patients in whom the cancer had reached the anal sphincter before the preoperative therapy. The distal margin was tumor free in these cases.

CONCLUSION

The results of our study have shown that in very low rectal cancer, preoperative therapy causes tumor downsizing in >80% of cases and in more than one-half enhances the distance between the tumor and anal sphincter. These modifications affect the primary surgical options, facilitating or making sphincter-saving surgery possible.

P27kip1 expression is associated with tumor response to preoperative chemoradiotherapy in rectal cancer

BACKGROUND

Our aim was to ascertain whether or not the response to preoperative chemoradiotherapy for rectal cancer is associated with p27kip1 and p53 protein expression.

METHODS

Thirty-eight patients (27 male, 11 female) with a mean age of 59 years (age range 33-87) and stage II-III rectal cancer received preoperative chemoradiotherapy (45-50.4 Gy; 5-FU 350 mg/m2/day and leucovorin 10 mg/m2/day). Thirty-one underwent low anterior resection; seven underwent abdominoperineal excision. Endoscopic tumor biopsies, performed before adjuvant therapy, were evaluated for: histologic type, tumor differentiation, mitotic index, and p27kip1 and p53 protein expression which were immunohistochemically determined. p53 expression was graded as: a) absent or present in < or =10% of tumor cells; b) present in 11-25%; c) present in 26-75%; and d) present in >75% of tumor cells. p27kip1 expression was assessed using both light microscopy (percent of stained cells x10 HPF) and cytometry with an image analysis workstation. Tumor response, ascertained with histology, was classified using a scale from 0 (no response) to 6 (complete pathologic response).

RESULTS

The mitotic index for the endoscopic biopsies was low in 14 cases, moderate in 17 cases, and high in 7 cases. p53 protein expression was found in 21 (a), 3 (b), 3 (c), and 11 (d) cases. The mean percentage of cells expressing the p27kip1 protein was 34 (range 0-77.14%). A close correlation was found between cytometric and light microscopy findings for p27kip1 (r2 = 0.92, P = .0001). Tumor differentiation was good in 5 cases, poor in 2 cases, and moderate in the remaining 31 cases. While the response to adjuvant therapy was good/complete in 25 (65.78%) cases, it was absent/poor in 13 (34.21%) cases. Univariate analysis associated type of adjuvant therapy (chemoradiotherapy, P = .0428) and p27kip1 protein lower expression (P = .0148) with a poor response to adjuvant treatment. Stepwise linear regression found overexpression of p53 and p27kip1 and young age to be independent variables that were linked to a good response to adjuvant therapy.

CONCLUSIONS

Lack of p27kip1 and p53 protein expression in rectal cancer is associated with a poor response to preoperative adjuvant therapy.

Usefulness of endorectal ultrasound after preoperative radiotherapy in rectal cancer: comparison between sonographic and histopathologic changes

PURPOSE

Our aim was to assess the advantages of endorectal ultrasound after preoperative radiotherapy in rectal cancer, its reliability in tumoral staging, and its capacity to identify completely sterilized lesions.

METHODS

From 1994 to 1997, 29 patients with rectal cancer were systematically subjected to endorectal ultrasound before and after preoperative radiotherapy. Each patient was administered 30 to 50 Gy, followed by surgery six to eight weeks after completion of radiotherapy. Endorectal ultrasound was performed using a biplanar (linear and sectorial) endorectal probe. The morphologic, quantitative, and echo-pattern changes of the irradiated tumor were examined. Results of ultrasound findings before and after radiotherapy and a histologic examination of the surgical specimens were compared. Histopathologic studies were used to evaluate macromicroscopical radiation-induced changes, case by case. A comparison between tumoral shrinkage and fibrotic replacement was made using the semiquantitative Dworak's method.

RESULTS

Morphologically and quantitatively, postradiation endorectal ultrasound showed the reappearance of anatomic cleavage planes, a considerable shrinkage of the tumor, and in low rectal tumors, an increase in the distance from the anorectal ring in more than 50 percent of the cases. These data had a direct influence on surgical treatment. Histologic examination showed that, in 28 out of 29 cases, fibrosis was the most dominant component of the irradiated lesions, varying by more than 50 to 100 percent of the lesion (four cases pTO). A comparison of postradiation endorectal ultrasound with histopathology revealed that fibrosis became the morphologic basis of ultrasound images; therefore, after radiotherapy, what endorectal ultrasound staged was no longer the tumor but the extent of fibrosis in the rectal wall. A histopathologic examination showed that the residual tumor, when present, was always within the fibrosis, never outside or separate from it. Postradiation endorectal ultrasound showed echo-pattern changes. Some of the changes (more echogenic and nonhomogeneous lesions) were histologically related to the persistence of the tumor to a considerable degree; other changes (reappearance of parietal layers) were related to complete sterilization of lesions in two of three cases.

CONCLUSIONS

From the morphologic and quantitative point of view, postradiation endorectal ultrasound provides oncologists and surgeons useful information to assess treatment effectiveness and plan the surgical approach. From the tumor staging point of view, our report presents a completely new concept: that six to eight weeks after radiotherapy, endorectal ultrasound no longer stages the tumor, but rather the fibrosis that takes its place. However, postradiation endorectal ultrasound is a valid tool, because the extent of fibrosis in the rectal wall is a direct indication of the depth of residual cancer. A residual tumor, when present, is always inside the fibrosis. Finally, however, as regards the capacity of endorectal ultrasound to exclude or indicate complete sterilization of the lesion, the actual significance of the echo-pattern changes we observed needs to be assessed further by studies on a large number of cases.

Molecular prognostic factors in rectal cancer treated by radiation and surgery

PURPOSE

The aim of this study was to determine the biologic significance of tumor response and the prognostic value of molecular markers in a group of patients with rectal cancer treated with preoperative radiation therapy and radical surgery.

METHODS

Microsatellite instability, microvessel count, and immunohistochemistry for proliferating cell nuclear antigen, p53, p21, bcl-2, and vascular endothelial growth factor were performed in the preradiation biopsy specimen of 72 patients with rectal cancer treated by preoperative radiation therapy and radical curative surgery. Preoperative tumor stage by endorectal ultrasound was compared with pathology stage of the resected specimen. Mean follow-up was 50 months.

RESULTS

Twenty-eight patients (39 percent) responded to radiation therapy. The response was complete in 8 (12 percent) and partial in 20 patients (27 percent). Tumors with positive nodes in the surgical specimen were less likely to have responded to preoperative radiation (P = 0.03). Only p21 expression was individually associated with response to radiation (56 vs. 30 percent; P = 0.03). Tumors that were p53-negative/p21-positive or p21-positive/bcl-2-positive were also more likely to respond to radiation (83 vs. 35 percent; P = 0.03 and 71 vs. 31 percent; P = 0.01, respectively). The tumor relapsed in 21 patients (29 percent): locally in 7 (10 percent) and distally in 14 (19 percent). Recurrence was associated with lack of response to radiation, female gender, distal tumor location, high proliferating cell nuclear antigen labeling index, and low microvessel count. Probability of survival was greater for patients with well or moderately differentiated tumors and tumors that responded completely to radiation.

CONCLUSIONS

Tumor response to radiation is associated with improved tumor control and overall survival rate, and p21 expression is a marker of tumor radiosensitivity in patients with rectal cancer. Furthermore, a high proliferating cell nuclear antigen labeling index and a low microvessel count in the preradiation biopsy specimen may be prognostic indicators for tumor recurrence.

[Oncologic and functional results of resections with direct delayed coloanal anastomosis in previously irradiated cancers of the lower rectum]

AIM OF THE STUDY

The aim of this study was to assess the oncology and functional outcome after preoperative radiotherapy and delayed coloanal anastomosis for cancers of the lower third of the rectum.

PATIENTS AND METHODS

From January 1988 to December 1997, 35 patients received preoperative radiotherapy (45 Gy) followed by rectal resection through a combined abdominal and transanal approach. Thirty patients had preoperative tumor staging with endorectal ultrasonography: uT1N0 = 2, uT2N0 = 6, uT2N+ = 2, uT3N0 = 6, and uT3N+ = 14. Colorectal resection was performed on average 32 days after the conclusion of radiotherapy, and the distal colon stump was pulled through the anal canal. On postoperative day 5, the colonic stump was resected and a direct coloanal anastomosis performed.

RESULTS

Pathological examination of the specimens revealed complete tumor sterilization in two cases, pT1N0 = 3, pT2N0 = 14, pT2N+ = 1, pT3N0 = 6, and pT3N+ = 9. There was no postoperative mortality and there was no leakage. One patient had a pelvic abscess, and another one had left colon necrosis which required re-operation. Median follow-up was 43 months (range 6-113). Two patients had locoregional recurrence, seven had distant metastasis, and 3 had both. Actuarial survival rate at 1, 3 and 5 years was 97%, 86%, and 72% respectively. The rate of local control at 5 years was 78%. Functional results were evaluated by a new scoring system. Function was considered good in 59 and 70% at 1 and 2 years respectively.

CONCLUSION

This new procedure is a safe and effective sphincter-preserving operation that avoids a diverting stoma. It is well adapted for patients receiving preoperative radiotherapy, with low local morbidity and good functional results.

Use of preoperative ultrasound staging for treatment of rectal cancer

INTRODUCTION

Transrectal ultrasound is the standard method for preoperative staging of rectal cancer. This study reviews the accuracy of transrectal ultrasound staging for T3 disease and its use in the selection of patients for neoadjuvant chemoradiation.

METHODS

One hundred seventeen patients underwent preoperative transrectal ultrasound evaluation for rectal cancer. Accuracy of transrectal ultrasound was evaluated among 70 patients not receiving preoperative chemoradiation. Forty-seven patients received neoadjuvant chemoradiation based on transrectal ultrasound results. Tumor downstaging and early recurrence were evaluated among 45 of 47 patients receiving neoadjuvant chemoradiation.

RESULTS

Among 70 nonirradiated patients, 19 were pathologic Stage pT3. Transrectal ultrasound correctly identified 18 of 19 patients with Stage pT3 (sensitivity, 94.7 percent). Transrectal ultrasound correctly identified 44 of 51 patients with less than pT3 disease (specificity, 86.3 percent). After preoperative chemoradiation in 45 patients with ultrasound Stage uT3 or uT4 tumors, 56 percent of them experienced a reduction in T stage. Residual nodal disease was found in 31 percent of patients. A complete pathologic response with no residual disease at operation was observed in 22 percent of patients. During a median follow-up period of 21 months after diagnosis, seven patients experienced a recurrence of their disease at a median of 12 months after diagnosis. Five of seven patients with recurrence were among a subgroup of ten patients who both failed to downstage T and had residual nodal disease at operation.

CONCLUSION

Transrectal ultrasound is an accurate modality for selecting patients for neoadjuvant treatment. Preoperative chemoradiation produced downstaging in 56 percent of patients. Factors related to early recurrence included residual nodal disease and failure to downstage T after neoadjuvant chemoradiation.

Radioterapia e cirurgia na abordagem do câncer do reto: revisão de literatura, fatores prognósticos e resultados de tratamento

O objetivo principal deste estudo foi avaliar os resultados da cirurgia isolada ou associada a radioterapia pré-operatória em pacientes portadores de adenocarcinoma do reto. Foram analisados retrospectivamente 96 pacientes submetidos a cirurgias curativas entre 1972 e 1993. A análise visou, principalmente, comparar as taxas de sobrevida global em cinco anos e de recidiva local. Quarenta e seis pacientes tratados por cirurgias isoladas tiveram taxas de sobrevida em cinco anos e de recidiva local de 51,7% e 26,9%, respectivamente, nos estádios II e III. Cinqüenta pacientes submeteram-se a radioterapia pré-operatória na dosagem de 4.500 cGy, em 25 sessões de 180 cGy, com taxas de sobrevi da em cinco anos e de recidiva local de 60,8% e 18,2%, respectivamente, nos estádios II e III. As diferenças entre os dois grupos terapêuticos não foram estatisticamente significativas. A análise multivariada demonstrou que o estadiamento da neoplasia, principalmente com relação à presença ou não de linfonodos regionais metastáticos, foi o fator prognóstico mais importante, independentemente do grupo terapêutico analisado. Baseados nos resultados apresentados, discutimos que a indicação da radioterapia em câncer do reto deve ser mais seletiva, com realização de cirurgia imediata em pacientes portadores de tumores retais móveis, mesmo infiltrativos na parede, irradiando no pós-operatório apenas os casos com maior risco de recidiva, de acordo com o resultado do exame anatomopatológico da peça cirúrgica. Pacientes portadores de tumores com mobilidade reduzida em relação às paredes pélvicas devem ser irradiados no pré-operatório com a finalidade de facilitação do ato cirúrgico e diminuição do risco de disseminação de células tumorais no intra-operatório e conseqüente diminuição das taxas de recidiva local.

Surgical aspects of colorectal carcinoma

Colorectal surgery remains the cornerstone of curative therapy for colorectal carcinoma. The development of new instruments permitting technical advances, however, as well as the advent of effective adjuvant therapies and the progress in staging and early detection, have changed some of the indications for surgery as well as surgical methods. Even so, emphasis has always been placed on thorough preoperative evaluation and staging. This article explores the current state of standard surgical care of the colorectal cancer patient with special attention given to preoperative evaluation, standard and controversial surgical therapies, and postoperative surveillance.

Preoperative staging of irradiated rectal cancers using digital rectal examination, computed tomography, endorectal ultrasound, and magnetic resonance imaging does not accurately predict T0,N0 pathology

PURPOSE

The postradiation preoperative staging results of 25 patients with rectal cancer who were found to have Stage T0,N0 lesions after surgery were examined. Our aim was to assess the ability of preoperative staging following radiation therapy to predict the absence of disease.

METHODS

From 1983 to 1994, 25 patients treated with preoperative radiation therapy for biopsy-proven rectal cancer were found to have no pathologic evidence of disease in the resected specimen (T0,N0). The preoperative postradiation disease staging results of these patients were compared with the postoperative pathologic findings. Each patient received 4,500 to 5,580 cGy during a five-week to six-week period, and four patients had preoperative chemotherapy. Surgical resection was performed six to eight weeks after completion of radiation therapy. All 25 patients were staged by digital rectal examination before surgery. In addition, 13 patients were assessed using computed tomography, 6 by endorectal ultrasound, and 1 by magnetic resonance imaging.

RESULTS

Most irradiated lesions were overstaged by radiologic assessment and physical examination. No technique could reliably distinguish between postradiation fibrosis and residual cancer. The negative predictive value for digital rectal examination was 24 percent. Computed tomography accurately staged 23 percent of lesions, and endorectal ultrasound predicted 17 percent of lesions correctly. The single patient evaluated by magnetic resonance imaging was overstaged and thought to have a T2 lesion.

CONCLUSIONS

Our ability to assess local eradication of rectal cancer following radiation therapy remains poor. Conventional imaging and clinical examination techniques are unable to safely predict which patients do not require surgical excision following curative radiation therapy for rectal cancer.

A clinical trial to evaluate the worth of preoperative multimodality therapy in patients with operable carcinoma of the rectum: a progress report of National Surgical Breast and Bowel Project Protocol R-03

PURPOSE

National Surgical Adjuvant Breast and Bowel Project Protocol R-03 was designed to determine the worth of preoperative chemotherapy and radiation therapy in the management of operable rectal cancer.

METHODS

Thus far, 116 patients of an eventual 900 with primary operable rectal cancer have been randomized to receive multimodality therapy to begin preoperatively (59 patients) or identical therapy beginning after curative surgery (57). All patients received seven cycles of 5-fluorouracil (FU)/leucovorin (LV) chemotherapy. Cycles 1 and 4 through 7 used a high-dose weekly FU regimen. In Cycles 2 and 3, FU and low-dose LV chemotherapy was given during the first and fifth week of radiation therapy (5,040 cGy). The preoperative arm (Group 1) received the first three cycles of chemotherapy and all radiation therapy before surgery. The postoperative arm (Group 2) received all radiation and chemotherapy after surgery. Primary study end points included disease-free survival and survival. Secondary end points included local recurrence, primary tumor response to combination therapy, tumor downstaging, and sphincter preservation.

RESULTS

Overall treatment-related toxicity was similar in both groups. Although seven preoperative patients had events after randomization that precluded surgery, eight events occurred during an equivalent follow-up period in the postoperative group. No patient was deemed inoperable because of progressive local disease. Sphincter-saving surgery was intended in 31 percent of Group 1 patients and 33 percent of Group 2 patients at the time of randomization. Such surgery was actually performed in 50 percent of the preoperatively treated patients and 33 percent of the postoperatively treated patients. The use of protective colostomy in patients undergoing sphincter-sparing surgery and the development of perioperative complications in all surgical patients were similar in both groups. There was evidence of tumor downstaging in evaluable patients undergoing preoperative therapy, with 8 percent of Group 1 patients having had a pathologic complete response.

CONCLUSION

These data do suggest that the preoperative chemotherapy and radiation therapy regimen used are, at least, as safe and tolerable as standard postoperative treatment. There is presently a trend to tumor downstaging and sphincter preservation in the preoperative arm. Whether this arm will have greater or lesser survival and long-term toxicity awaits the completion of this relevant study.

Endorectal ultrasound of T3 and T4 rectal cancers after preoperative chemoradiation

PURPOSE

This study was undertaken to assess the accuracy and ability of endorectal ultrasound (ERUS) to predict changes in rectal tumor stage after a preoperative chemoradiation protocol.

METHODS

Since December 1990, all rectal malignancies at our institution have been preoperatively staged with ERUS. ERUS has been an essential tool in preoperative staging of rectal cancer patients, possessing an overall accuracy of 84 percent for T stage and 81 percent for lymph node status in our hands (Williamson PR, unpublished data). Beginning in July 1992, all patients staged with T3 or T4 lesions on initial ERUS have been entered into a protocol consisting of preoperative chemoradiation therapy (CRT). This protocol consists of patients receiving 4,500 to 5,040 rads for five to eight weeks and concomitantly receiving sensitizing doses of 5-fluorouracil and/or leucovorin. All patients were scheduled for sphincter-saving or abdomino-perineal resections six to eight weeks following completion of CRT. A repeat ERUS was performed on each patient one week before surgery.

RESULTS

The study group consisted of 15 patients who completed CRT, including 12 males and 3 females. Evidence of tumor shrinkage via ERUS measurement was seen in all patients. Average tumor shrinkage as assessed by ERUS was 16 percent by width and 32 percent by depth of invasion. Sonographic level of invasion and nodal status were each downstaged in 38 percent of patients. Pathologic evaluation comparison revealed that the level of invasion was downstaged in 47 percent and nodal status in 88 percent compared with initial ERUS staging. Of those patients downstaged, 4 of 11 (36 percent) revealed no tumor in the pathology specimen.

CONCLUSIONS

We conclude from our early experience that although ERUS offers a method for assessing degree of shrinkage and downstaging of T3 and T4 lesions after CRT, presently it does not closely predict the pathologic results. Results are strongly related to the experience of the ultrasonographer. The ability to distinguish tumor from radiation-induced changes to perirectal tissues is under continued investigation, and a new method of interpreting the data obtained by ERUS after CRT will need to be established.

Magnetic resonance imaging of rectal carcinoma: a prospective study

Accurate preoperative staging of rectal cancer is necessary to identify patients who might benefit from adjuvant therapy. Magnetic resonance imaging (MRI) was evaluated in 20 consecutive patients with rectal cancer undergoing 'curative' surgery. Detailed histopathological examination of the resected lesion was correlated with findings of MRI. MRI staging concurred with histological staging in 18 of 20 patients using the Dukes or tumour node metastasis classification but in only 14 using the modified Astler-Coller system. MRI diagnosed transmural invasion in all but one patient with microscopic mural invasion (positive predictive value, 100 per cent; negative predictive value, 80 per cent; overall accuracy, 95 per cent). MRI correctly diagnosed tumour deposits or involved lymph nodes in 12 patients. MRI overstaged one patient, in whom nodes that were enlarged on imaging studies were negative at histological examination (positive predictive value, 92 per cent; negative predictive value, 100 per cent; overall accuracy, 95 per cent). MRI has a role in selected cases for the preoperative assessment of rectal carcinoma.

Surgical adjuvant therapy for rectal cancer: present options

Recent advances have been made with the publication of the results of GITSG and NCCTG trials, which demonstrated the significant improvement of survival by combined postoperative radiochemotherapy protocols for Stage II and III rectal cancer. These data show that systemic chemotherapy has a decisive role to play in this policy. Some of the advantages of preoperative irradiation compared with postoperative radiation therapy consist of the improvement of resectability of T4 tumors and the anal preservation for low-lying cancers. These data suggest that preoperative chemoradiotherapy should be applied not only to T4 tumors but also to all T3 tumors even when the transrectal extension is limited. The most usual protocol combines 5-fluorouracil (300-350 mg/m2/day) and leucovorin (20 mg/m2/day) for 5 days, followed by radiation therapy (30-35 Gy in 10 fractions within 12-15 days), with surgery taking place 4 to 8 weeks later, after the tumor has been restaged. Systemic therapy is continued for four more months. T2 cancers should not be excluded from the benefit of preoperative irradiation.