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Preoperative radiation therapy followed by local excision
Preoperative Radiation Therapy Followed by Local Excision Neelofur R. Ahmad and Deborah A. Nagle Radiation therapy followed by local excision results in local control rates that appear comparable to those of local excision alone (in highly selected patients) or local excision followed by adjuvant radiation therapy. A significant drawback of this approach, however, is the potential loss of important histological information, such as risk of lymph node metastasis, depth of tumor penetration, and presence of lymphatic or vascular
~
hough cure of cancer remains the overriding concern of physicians caring for patients with rectal cancer, increasing attention is being directed toward preservation of the individual's quality of life. For many patients with cancer of the distal rectum (3 to 6 cm from the anal verge), quality of life is synonymous with sphincter preservation and avoidance of a permanent colostomy. A variety of therapeutic approaches have been investigated in an eflbrt to increase sphincter preservation without compromising local control and survival rates, including local excision alone, local excision followed by adjuvant radiation or chemoradiation therapy, and preoperative radiation therapy or chemoradiation therapy followed by local excision or radical sphincterpreserving surgery. The focus of this article is on the use of preoperative radiation therapy or chemoradiation therapy followed by local excision.
Background The closest comparison of the results of radiation therapy followed by local excision for clinical stage T1/T2 lesions is with the much larger experience with either local excision alone or local excision followed by adjuvant radiation therapy or chemoradiation therapy for clinical T1/T2 cancers. The largest published experience with preoperative radiation therapy followed by local excision is that of Mohiuddin et al, 1 who treated 18 patients with clinical stage T1/T2 rectal cancer with 40 to 45 Gy pelvic radiation therapy followed by full-thickness local excision 4 to 8
From the Deparlment of Radiation Oncology(Abroad) and Division of Colorectal Surgery (Nagle),Jefferson Medical Collegeof ThomasJefferson University,Philadelphia,PA. Address reprint requests to Neelofur R. Abroad, MD, Jefferson~Lower BucksRadiation OncologyCenter,501 Bath Rd, Bristol, PA 19007. Col~right 9 1998 by W.B. Saunders Company 1053-4296/98/0801-000658.00/0
36
invasion. Radiation therapy followed by local excision may be an option for treatment of more advanced T3 rectal cancers in patients who either refuse radical surgery or are medically unfit. The available data in the literature do not support the routine use of local excision after radiation therapy in otherwise healthy patients with locally advanced rectal cancer.
Copyright9 1998by W.B. Saunders Company
weeks later. The postoperative complication rate was 11% (2 of 18 patients). With a median follow-up time of 40 months, the crude local recurrence rate was 11% (2 of 18 patients), and the 5-year actuarial survival rate was 92%. Investigators at the Henri Mondor Hospital treated 15 clinical stage T1/T2 rectal cancer patients with 35 Gy of external-beam radiation therapy, local excision, and 20 to 25 Gy of brachytherapy. With a median follow-up time of 41 months, the crude local failure rate was 13% (2 of 15 patients) .2 These results compare favorably with those obtained with local excision alone or followed by adjuvant radiation therapy or chemoradiation therapy in carefully selected patients. For T1 lesions treated by local excision alone, the local recurrence rates range from 0% to 15%.3-7 Gall and Hermanek 3 observed a crude local failure rat e of 7To after local excision of T 1 rectal cancer among 54 patients. The median follow-up time was 77.5 months. Similarly, Willett et aP reported a 10% local recurrence rate among 20 patients treated with local excision alone for clinical stage T1 rectal cancer. The median follow-up time was 36 months. 4 In general, local failure rates are higher after local excision alone for T2 cancers. Both Gall and Hermanek 3 and Willett et aP reported 20% local recurrence rates in this setting. Others, however, have observed much higher local recurrence rates. Horn et al7 had a 43% local recurrence rate after local excision among 14 patients with T2 lesions. In an effort to improve local control rates among patients with unfavorable T1 or T2 lesions, adjuvant radiation therapy with or without chemotherapy has been investigated/-11 Reported local failure rates range from 0% to 17% with this approach. Surgical salvage rates after local failure vary widely, with reported rates ranging from 0% to 100%.3-11The average salvage rate, however, appears to be around 50% to 60%. The routine use of preoperative radiation therapy
Seminars in Radiation Oncolog5 Vol 8, No 1 (Janua~), 199& pp 36-38
PreoperativeRadiation TherapyFollowedby Local Excision
followed by local excision for stage T1/T2 rectal cancer has not gained widespread acceptance. This is primarily because of the potential loss of important histological information after radiation therapy. Appropriate selection of patients for local excision hinges on accurate preoperative staging followed by pathological confirmation of the clinical stage. Several authors have reported the prognostic importance of features such as depth of tumor penetration, differentiation, and presence of blood or lymphatic vessel invasion, particularly with regard to the likelihood of lymphatic metastases. 12-14If a clinical stage T1 tumor is locally excised initially, a favorable histological profile may save the patient unnecessary adjuvant therapy if the risk of lymphatic metastasis is determined to be low. Thus, there is potential for overtreatment of patients if all comers are irradiated and histological assessment made after the fact. It is also possible, however, that unfavorable histological features might not remain prognostic given potential sterilization of lymphatic metastases in patients treated with preoperative radiation therapy. Because it is unlikely that a prospective, randomized trial will be conducted to determine the relative efficacy of preoperative versus postoperative adjuvant therapy tbr clinical T1 or T2 lesions, the choice of approach for these early tumors is largely subject to individual physician or institutional biases. In theory, the single greatest advantage of preoperative radiation therapy or chemoradiation therapy is the potential for downstaging of locally advanced clinical T3 or T4 cancers, which might not have been amenable to sphincter-preserving surgery otherwise. Most investigators, however, have tbcused on radical sphincter-sparing surgery, such as low anterior resection or low anterior resection with coloanal anastomosis, after preoperative radiation therapy or chemoradiation therapy for locally advanced cancer. There are few data regarding the curative potential of local excision after preoperative radiation therapy for such advanced lesions. Again the largest such experience is that of Mohiuddin et al, in which 30 patients with clinical stage T3 cancers received 55 Gy of radiation therapy followed by local excision. Of these patients, 15 were treated by local excision because their poor medical condition precluded radical surgery. An additional 15 patients received local excision after clinical regression of their tumors after radiation therapy, such that the postradiation therapy lesions were judged to be either clinical stage T2 or less than 3 cm in diameter. In the first group, the crude local failure rate was 20% (3 of 15), and the 5-year actuarial
37
survival rate was 74%. In the second group, one patient had a pathological stage T3 lesion after local excision and was converted to an abdominoperineal resection. There were no local failures among the remaining 14 local excision patients, and the 5-year actuarial survival rate was 88%.t No data were provided, however, regarding the overall proportion of patients with clinical stage T3 presentations who might become amenable to local excision after preoperative therapy. Thus, it is difficult to translate these results into a useful guide for clinical practice.
Selection Criteria Based on the experience ofMohiuddin et al, the most important factor for selection of patients for local excision after radiation therapy for locally advanced rectal cancer appears to be downstaging of the lesion to clinical stage T2 or less. This remains a highly subjective determination, however, in the irradiated patient. To date, radiographic studies such as endorectal ultrasonography (ERUS), computed tomography, and magnetic resonance imaging have been inaccurate in determining T-stage after radiation therapy for rectal cancer. Williamson et a115imaged 15 patients with ERUS before and after preoperative chemoradiation therapy for clinical stage T3 or T4 rectal cancer. After chemoradiation therapy, 38% of patients were downstaged by ERUS criteria for level of invasion and nodal status. Pathologically, however, level of invasion was downstaged in 47% and nodal status in 88% compared with initial ERUS staging. The authors concluded that presently ERUS after chemoradiation therapy does not predict pathological results accurately. 15 Another study by Kahn et al, L6evaluated the ability to assess local eradication of rectal cancer after radiation therapy using digital rectal examination and radiographic studies. After preoperative radiation therapy, digital rectal examination, computed tomography, and ERUS accurately staged only 24%, 23%, and 17% of lesions among 25 patients who had pathologically confirmed TO cancer. A single patient who was evaluated by magnetic resonance imaging was overstaged as well.16 Thus, although it may possible to ascertain downstaging by digital examination in some rectal cancer patients after radiation therapy, it is unclear how much confidence one can place on such determinations. Given the unreliability of radiographic staging of rectal cancer after radiation therapy and the lack of documentation of the accuracy of digital examination after radiation therapy, it is difficult to justify
38
Ahmad and Nagle
p e r f o r m i n g local excision, r a t h e r t h a n definitive surget% a l t e r p r e o p e r a t i v e radiation t h e r a p y or c h e m o radiation t h e r a p y for patients p r e s e n t i n g with clinically a d v a n c e d lesions. O n l y u n d e r circumstances in which the patient a d a m a n t l y refuses radical surgery or is medically unsuitable for such a procedure could one r e c o m m e n d this approach.
Conclusions T h e results of p r e o p e r a t i v e radiation t h e r a p y followed by local excision appear to be c o m p a r a b l e to those of local excision alone or local excision plus postoperative radiation t h e r a p y or c h e m o r a d i a t i o n t h e r a p y for patients w i t h clinical stage T 1 / T 2 rectal cancer. T h e r e is a paucity of published d a t a w i t h this approach, however. Most investigators favor local excision as the initial t r e a t m e n t so that histological i n f o r m a t i o n m a y h e l p d e t e r m i n e the n e e d for adjuv a n t therapy. For p a t i e n t s with m o r e a d v a n c e d T3 lesions at presentation, preoperative radiation therapy or c h e m o r a d i a t i o n t h e r a p y followed by local excision m a y offer a chance for sphincter preservation in patients who otherwise would require a b d o m i n o p e r i neal resection. G i v e n the limited d a t a and the potential difficulties in assessing a d e q u a t e t u m o r downstaging after p r e o p e r a t i v e therapy, however, such an approach should not be considered standard.
References I. Mohiuddin M, Marks G, Bannon J: High-dose preoperative radiation and full thickness local excision: A new option for selected T3 distal rectal cancers. IntJ Radiat Oncol Biol Phys 30:845-849, 1994 2. Despretz J, Otmezguine Y, Grimard L, et al: Conservative management of tumors of the rectum by radiotherapy and local excision. Dis Colon Rectum 33:113-116, 1990
3. Gall FP, Hermanek P: Update of the German experience with local excision of rectal cancer. Surg Oncol Clin North Ana 1:99-109, 1992 4. Willett CG, Tepper JE, Donnelly S, et al: Patterns of failure following local excision and local excision and postoperative radiation therapy for invasive rectal adenocarcinoma. J Clin Oncol 7:1003-1008, 1989 5. Germ'd A, PectorJC, FerreiraJ: Local excision as conservative treatment for small rectal cancer. EurJ Surg Oncol 15:544546, 1989 6. Said S, Huber P, Pichlmaier H: Technique and clinical results of endorectal surgery. Surgery t 13:65, 1993 7. Horn A, Halvorsen JF, Morild I: Transanat extirpation for early rectal cancer. Dis Colon Rectum 32:769-772, 1989 8. Wood WC, Wiltett CG: Update of the Massachusetts General Hospital experience of combined local excision and radiotherapy for rectal cancer. Surg Oncol Clin North Am 1:131136, 1992 9. Steele G, Busse PM, Huberman MS, et al: A pilot study of sphincter-sparing management of adneocarcinoma of the rectum. Arch Surg 126:696-702, 1991 10. Minsky BD, Enker WE, Cohen AM, et al: Local excision and postoperative radiation therapy for rectal cancer. A m J Clin Oncol 17:411-416, 1994 11. Ota DM, Skibber J, Rich TA: M.D. Anderson Cancer Center experience with local excision and multimodatity therapy for rectal cancer. Surg Oncol Clin NorthAm 1:147-152, 1992 12. Tanaka S, Yokota T, Saito D, et al: Clinicopathologic features of early rectal carcinoma and indications for endoscopic treatment. Dis Colon Rectum 39:959-963, 1995 13. Minsky BD, Rich T, Recht A, et al: Selection criteria for local excision with or without adjuvant radiation therapy for rectal cancer. Cancer 63:1421-1429, 1989 14. BrodskyJ, Richard G, Cohen A, et al: Variables correlated with the risk of lymph node metastasis in early rectal cancer. Cancer 69:322-326, 1992 15. Williamson PR, Hellinger IvID,Larach SW, et al: Endorectal ultrasound of T3 and T4 recta] cancers after preoperative chemoradiation. Dis Colon Rectum 39:45-49, 1996 I6. Kahn H, Alexander A, RakinicJ, et al: Preoperative staging of irradiated rectal cancers using digital rectal examination, computed tomography, endorectal ultrasound, and magnetic resonance imaging does not accurately predict TO, NO pathology. Dis Colon Rectum 40:140-144, 1997
~
hough cure of cancer remains the overriding concern of physicians caring for patients with rectal cancer, increasing attention is being directed toward preservation of the individual's quality of life. For many patients with cancer of the distal rectum (3 to 6 cm from the anal verge), quality of life is synonymous with sphincter preservation and avoidance of a permanent colostomy. A variety of therapeutic approaches have been investigated in an eflbrt to increase sphincter preservation without compromising local control and survival rates, including local excision alone, local excision followed by adjuvant radiation or chemoradiation therapy, and preoperative radiation therapy or chemoradiation therapy followed by local excision or radical sphincterpreserving surgery. The focus of this article is on the use of preoperative radiation therapy or chemoradiation therapy followed by local excision.
Background The closest comparison of the results of radiation therapy followed by local excision for clinical stage T1/T2 lesions is with the much larger experience with either local excision alone or local excision followed by adjuvant radiation therapy or chemoradiation therapy for clinical T1/T2 cancers. The largest published experience with preoperative radiation therapy followed by local excision is that of Mohiuddin et al, 1 who treated 18 patients with clinical stage T1/T2 rectal cancer with 40 to 45 Gy pelvic radiation therapy followed by full-thickness local excision 4 to 8
From the Deparlment of Radiation Oncology(Abroad) and Division of Colorectal Surgery (Nagle),Jefferson Medical Collegeof ThomasJefferson University,Philadelphia,PA. Address reprint requests to Neelofur R. Abroad, MD, Jefferson~Lower BucksRadiation OncologyCenter,501 Bath Rd, Bristol, PA 19007. Col~right 9 1998 by W.B. Saunders Company 1053-4296/98/0801-000658.00/0
36
invasion. Radiation therapy followed by local excision may be an option for treatment of more advanced T3 rectal cancers in patients who either refuse radical surgery or are medically unfit. The available data in the literature do not support the routine use of local excision after radiation therapy in otherwise healthy patients with locally advanced rectal cancer.
Copyright9 1998by W.B. Saunders Company
weeks later. The postoperative complication rate was 11% (2 of 18 patients). With a median follow-up time of 40 months, the crude local recurrence rate was 11% (2 of 18 patients), and the 5-year actuarial survival rate was 92%. Investigators at the Henri Mondor Hospital treated 15 clinical stage T1/T2 rectal cancer patients with 35 Gy of external-beam radiation therapy, local excision, and 20 to 25 Gy of brachytherapy. With a median follow-up time of 41 months, the crude local failure rate was 13% (2 of 15 patients) .2 These results compare favorably with those obtained with local excision alone or followed by adjuvant radiation therapy or chemoradiation therapy in carefully selected patients. For T1 lesions treated by local excision alone, the local recurrence rates range from 0% to 15%.3-7 Gall and Hermanek 3 observed a crude local failure rat e of 7To after local excision of T 1 rectal cancer among 54 patients. The median follow-up time was 77.5 months. Similarly, Willett et aP reported a 10% local recurrence rate among 20 patients treated with local excision alone for clinical stage T1 rectal cancer. The median follow-up time was 36 months. 4 In general, local failure rates are higher after local excision alone for T2 cancers. Both Gall and Hermanek 3 and Willett et aP reported 20% local recurrence rates in this setting. Others, however, have observed much higher local recurrence rates. Horn et al7 had a 43% local recurrence rate after local excision among 14 patients with T2 lesions. In an effort to improve local control rates among patients with unfavorable T1 or T2 lesions, adjuvant radiation therapy with or without chemotherapy has been investigated/-11 Reported local failure rates range from 0% to 17% with this approach. Surgical salvage rates after local failure vary widely, with reported rates ranging from 0% to 100%.3-11The average salvage rate, however, appears to be around 50% to 60%. The routine use of preoperative radiation therapy
Seminars in Radiation Oncolog5 Vol 8, No 1 (Janua~), 199& pp 36-38
PreoperativeRadiation TherapyFollowedby Local Excision
followed by local excision for stage T1/T2 rectal cancer has not gained widespread acceptance. This is primarily because of the potential loss of important histological information after radiation therapy. Appropriate selection of patients for local excision hinges on accurate preoperative staging followed by pathological confirmation of the clinical stage. Several authors have reported the prognostic importance of features such as depth of tumor penetration, differentiation, and presence of blood or lymphatic vessel invasion, particularly with regard to the likelihood of lymphatic metastases. 12-14If a clinical stage T1 tumor is locally excised initially, a favorable histological profile may save the patient unnecessary adjuvant therapy if the risk of lymphatic metastasis is determined to be low. Thus, there is potential for overtreatment of patients if all comers are irradiated and histological assessment made after the fact. It is also possible, however, that unfavorable histological features might not remain prognostic given potential sterilization of lymphatic metastases in patients treated with preoperative radiation therapy. Because it is unlikely that a prospective, randomized trial will be conducted to determine the relative efficacy of preoperative versus postoperative adjuvant therapy tbr clinical T1 or T2 lesions, the choice of approach for these early tumors is largely subject to individual physician or institutional biases. In theory, the single greatest advantage of preoperative radiation therapy or chemoradiation therapy is the potential for downstaging of locally advanced clinical T3 or T4 cancers, which might not have been amenable to sphincter-preserving surgery otherwise. Most investigators, however, have tbcused on radical sphincter-sparing surgery, such as low anterior resection or low anterior resection with coloanal anastomosis, after preoperative radiation therapy or chemoradiation therapy for locally advanced cancer. There are few data regarding the curative potential of local excision after preoperative radiation therapy for such advanced lesions. Again the largest such experience is that of Mohiuddin et al, in which 30 patients with clinical stage T3 cancers received 55 Gy of radiation therapy followed by local excision. Of these patients, 15 were treated by local excision because their poor medical condition precluded radical surgery. An additional 15 patients received local excision after clinical regression of their tumors after radiation therapy, such that the postradiation therapy lesions were judged to be either clinical stage T2 or less than 3 cm in diameter. In the first group, the crude local failure rate was 20% (3 of 15), and the 5-year actuarial
37
survival rate was 74%. In the second group, one patient had a pathological stage T3 lesion after local excision and was converted to an abdominoperineal resection. There were no local failures among the remaining 14 local excision patients, and the 5-year actuarial survival rate was 88%.t No data were provided, however, regarding the overall proportion of patients with clinical stage T3 presentations who might become amenable to local excision after preoperative therapy. Thus, it is difficult to translate these results into a useful guide for clinical practice.
Selection Criteria Based on the experience ofMohiuddin et al, the most important factor for selection of patients for local excision after radiation therapy for locally advanced rectal cancer appears to be downstaging of the lesion to clinical stage T2 or less. This remains a highly subjective determination, however, in the irradiated patient. To date, radiographic studies such as endorectal ultrasonography (ERUS), computed tomography, and magnetic resonance imaging have been inaccurate in determining T-stage after radiation therapy for rectal cancer. Williamson et a115imaged 15 patients with ERUS before and after preoperative chemoradiation therapy for clinical stage T3 or T4 rectal cancer. After chemoradiation therapy, 38% of patients were downstaged by ERUS criteria for level of invasion and nodal status. Pathologically, however, level of invasion was downstaged in 47% and nodal status in 88% compared with initial ERUS staging. The authors concluded that presently ERUS after chemoradiation therapy does not predict pathological results accurately. 15 Another study by Kahn et al, L6evaluated the ability to assess local eradication of rectal cancer after radiation therapy using digital rectal examination and radiographic studies. After preoperative radiation therapy, digital rectal examination, computed tomography, and ERUS accurately staged only 24%, 23%, and 17% of lesions among 25 patients who had pathologically confirmed TO cancer. A single patient who was evaluated by magnetic resonance imaging was overstaged as well.16 Thus, although it may possible to ascertain downstaging by digital examination in some rectal cancer patients after radiation therapy, it is unclear how much confidence one can place on such determinations. Given the unreliability of radiographic staging of rectal cancer after radiation therapy and the lack of documentation of the accuracy of digital examination after radiation therapy, it is difficult to justify
38
Ahmad and Nagle
p e r f o r m i n g local excision, r a t h e r t h a n definitive surget% a l t e r p r e o p e r a t i v e radiation t h e r a p y or c h e m o radiation t h e r a p y for patients p r e s e n t i n g with clinically a d v a n c e d lesions. O n l y u n d e r circumstances in which the patient a d a m a n t l y refuses radical surgery or is medically unsuitable for such a procedure could one r e c o m m e n d this approach.
Conclusions T h e results of p r e o p e r a t i v e radiation t h e r a p y followed by local excision appear to be c o m p a r a b l e to those of local excision alone or local excision plus postoperative radiation t h e r a p y or c h e m o r a d i a t i o n t h e r a p y for patients w i t h clinical stage T 1 / T 2 rectal cancer. T h e r e is a paucity of published d a t a w i t h this approach, however. Most investigators favor local excision as the initial t r e a t m e n t so that histological i n f o r m a t i o n m a y h e l p d e t e r m i n e the n e e d for adjuv a n t therapy. For p a t i e n t s with m o r e a d v a n c e d T3 lesions at presentation, preoperative radiation therapy or c h e m o r a d i a t i o n t h e r a p y followed by local excision m a y offer a chance for sphincter preservation in patients who otherwise would require a b d o m i n o p e r i neal resection. G i v e n the limited d a t a and the potential difficulties in assessing a d e q u a t e t u m o r downstaging after p r e o p e r a t i v e therapy, however, such an approach should not be considered standard.
References I. Mohiuddin M, Marks G, Bannon J: High-dose preoperative radiation and full thickness local excision: A new option for selected T3 distal rectal cancers. IntJ Radiat Oncol Biol Phys 30:845-849, 1994 2. Despretz J, Otmezguine Y, Grimard L, et al: Conservative management of tumors of the rectum by radiotherapy and local excision. Dis Colon Rectum 33:113-116, 1990
3. Gall FP, Hermanek P: Update of the German experience with local excision of rectal cancer. Surg Oncol Clin North Ana 1:99-109, 1992 4. Willett CG, Tepper JE, Donnelly S, et al: Patterns of failure following local excision and local excision and postoperative radiation therapy for invasive rectal adenocarcinoma. J Clin Oncol 7:1003-1008, 1989 5. Germ'd A, PectorJC, FerreiraJ: Local excision as conservative treatment for small rectal cancer. EurJ Surg Oncol 15:544546, 1989 6. Said S, Huber P, Pichlmaier H: Technique and clinical results of endorectal surgery. Surgery t 13:65, 1993 7. Horn A, Halvorsen JF, Morild I: Transanat extirpation for early rectal cancer. Dis Colon Rectum 32:769-772, 1989 8. Wood WC, Wiltett CG: Update of the Massachusetts General Hospital experience of combined local excision and radiotherapy for rectal cancer. Surg Oncol Clin North Am 1:131136, 1992 9. Steele G, Busse PM, Huberman MS, et al: A pilot study of sphincter-sparing management of adneocarcinoma of the rectum. Arch Surg 126:696-702, 1991 10. Minsky BD, Enker WE, Cohen AM, et al: Local excision and postoperative radiation therapy for rectal cancer. A m J Clin Oncol 17:411-416, 1994 11. Ota DM, Skibber J, Rich TA: M.D. Anderson Cancer Center experience with local excision and multimodatity therapy for rectal cancer. Surg Oncol Clin NorthAm 1:147-152, 1992 12. Tanaka S, Yokota T, Saito D, et al: Clinicopathologic features of early rectal carcinoma and indications for endoscopic treatment. Dis Colon Rectum 39:959-963, 1995 13. Minsky BD, Rich T, Recht A, et al: Selection criteria for local excision with or without adjuvant radiation therapy for rectal cancer. Cancer 63:1421-1429, 1989 14. BrodskyJ, Richard G, Cohen A, et al: Variables correlated with the risk of lymph node metastasis in early rectal cancer. Cancer 69:322-326, 1992 15. Williamson PR, Hellinger IvID,Larach SW, et al: Endorectal ultrasound of T3 and T4 recta] cancers after preoperative chemoradiation. Dis Colon Rectum 39:45-49, 1996 I6. Kahn H, Alexander A, RakinicJ, et al: Preoperative staging of irradiated rectal cancers using digital rectal examination, computed tomography, endorectal ultrasound, and magnetic resonance imaging does not accurately predict TO, NO pathology. Dis Colon Rectum 40:140-144, 1997