Preoperative Radiotherapy Alone or Combined With Chemotherapy Followed by Transanal Excision for Rectal Adenocarcinoma

Transanal excision with radiation therapy for rectal adenocarcinoma

OBJECTIVE

To evaluate the efficacy of transanal excision (TAE) combined with radiotherapy for rectal adenocarcinoma, assess the ability of pretreatment endoscopic ultrasound (EUS) to predict failures, and determine the prognostic value of downstaging and complete pathological response.

DESIGN

Retrospective outcomes study.

SETTING

Radiation oncology clinic.

PARTICIPANTS

Thirty-eight patients with rectal adenocarcinoma.

METHODS

The medical records of patients treated with radiotherapy from 1998 to 2008 and followed for a median of 5.9 years were reviewed.

RESULTS

Kaplan-Meier estimates of freedom from selected endpoints at 5 years after treatment were: overall survival, 79%; cause-specific survival, 91%; local control, 90%; and freedom from distant metastasis, 76%. Seven patients (21%) had eventual abdominoperineal resection or lower anterior resection, four patients had local recurrence, and three patients had incomplete treatment or poor margins. T3 lesions clinically staged by EUS were a predictor of local failure (P=0.0110), but not distant metastasis (P=0.35). Patients with either a pathological or clinical T3 lesion did not have a significantly greater rate of metastasis (P=0.096). Patients who were downstaged did not have a significantly different rate of local recurrence or metastasis. Patients who experienced a complete pathological response did not have a significantly different rate of local control or distant metastasis.

CONCLUSION

Patients with early-stage rectal lesions who undergo preoperative or postoperative radiation and TAE have similar outcomes to those who undergo abdominoperineal resection; local recurrence was higher for patients with T3 lesions when both were compared. Abdominal surgery should be considered for these patients. TAE is reasonable when patients are unwilling or unable to tolerate the morbidity of traditional transabdominal surgery.

Radiotherapy in the treatment of resectable rectal adenocarcinoma

The goal of treatment is to cure whereas maintaining sphincter function and minimizing toxicity. Although the mainstay of the treatment is surgery, radiotherapy (RT) is used in a substantial proportion of patients depending on the location and extent of the tumor. The aim of this article is to discuss the role of RT in patients with resectable rectal adenocarcinoma. This article is a review of the pertinent literature. Results show that patients with T1N0 exophytic, well to moderately differentiated, mobile tumors < or = 3 cm in diameter may be treated with either transanal excision or endocavitary RT. The probability of cure with either approach is approximately 80% to 90% and depends on selection criteria. The advantages of endocavitary RT are that it is an outpatient procedure requiring, at most, local anesthesia and is suitable for elderly, infirm patients. The disadvantage is that few of these treatment units are available. Patients who experience a local-regional recurrence may be surgically salvaged. Patients who undergo transanal excision and have unfavorable pathologic findings including equivocal or close margins, poor differentiation, invasion of the muscularis propria, and/or endothelial-lined space invasion have a high risk of local-regional recurrence after surgery alone. The addition of postoperative RT improves the likelihood of cure from 85% to 90%. Patients presenting with unfavorable tumors that are borderline resectable with a transanal excision may be downstaged with preoperative RT and rendered suitable for a wide local excision. The addition of concomitant chemotherapy probably enhances downstaging and may improve the likelihood of sphincter preservation. Patients with T3 and/or N1 rectal cancers have a relatively high probability of local-regional recurrence after surgery alone. Preoperative RT and postoperative RT combined with adjuvant chemotherapy have been shown to significantly reduce the risk of local-regional recurrence and improve survival. Whether preoperative RT alone or combined with chemotherapy is more efficacious than postoperative chemoradiation remains unclear. Endocavitary RT or transanal excision is suitable for patients with T1N0 cancers. Depending on tumor location and extent, adjuvant RT may improve the probability of local-regional control and survival for patients with locally advanced rectal adenocarcinomas.

Local excision for more advanced rectal tumors

Over the past 20 years, local excision (LE) of T1 rectal cancer was increasingly established and represents an oncologically established technique. In contrast, the situation for T2 tumors is less clear and has only been investigated in small patient collectives. LE for T2 tumors is thus discussed controversially.

MATERIALS AND METHODS

In addition to our own patients with T2 rectal cancer treated locally (n=40), we have analysed the local recurrence (LR) rates after LE alone (n=124), after immediate conventional radical reoperation (n=29), after adjuvant (chemo)-radiotherapy (n=294) and those after neoadjuvant chemoradiotherapy (nCRT) (n=269) using a PubMed search.

RESULTS

LR rates of low-grade T2 tumors after R0 resection by LE alone was 19%. If additional prognostically unfavorable findings were present, the LR rate rose to 52%. By immediate radical reoperation the LR rate was decreased to 7%, whereas that after adjuvant therapy was 16%. In contrast, LE of more advanced tumors after nCRT resulted in LR rates of 9%.

DISCUSSION

LE alone of T2 rectal cancer should not be performed, and after adjuvant chemoradiotherapy the risk of developing LR was also high. In cases with unexpected T2 finding after LE, immediate conventional reoperation can represent an adequate oncological therapy, because it reveals comparable results to those obtained by primary radical resection. First results after nCRT followed by LE showed favorable results with low LR rates. If the indication for LE of T2 cancers can be extended to patients after nCRT in the future will have to be determined in prospective mutlticentre studies.

Preoperative chemoradiation followed by transanal excision for rectal cancer

BACKGROUND

This study was conducted to assess the efficacy of preoperative chemoradiation followed by transanal excision among patients with locally advanced lower rectal cancer.

METHODS

Between May 1994 and June 2005, 73 patients with locally advanced lower rectal cancer were treated with curative intent by preoperative chemoradiation followed by surgical resection. Transanal excision was performed in 9 patients due to either the absolute refusal of a permanent stoma by the patient (n = 8) or medical comorbidity (n = 1). Sixty-four patients were treated by radical proctectomy. Preoperative 5-fluorouracil-based chemotherapy and pelvic radiation (4500 to 5040 cGy) were followed by surgery 6 wk after treatment, and all patients except one with transanal excision received postoperative 5-fluorouracil-based chemotherapy during the first year after surgery.

RESULTS

The mean follow-up period was 91 mo (range, 50 to 127 mo); median follow-up was 94 mo. One local recurrence occurred at 30 mo after transanal excision (11.1%); 5 in 64 patients who received radical proctectomy (7.8%) experienced local recurrences. The disease-free survival rate at 10 y was 77.8% in transanal excision group compared with a rate of 62.7% among radical proctectomy patients (P = 0.335). The overall survival rate at 10 y was 88.9% in transanal excision group compared with 74.2% among radical proctectomy patients (P = 0.424).

CONCLUSIONS

Transanal excision after preoperative chemoradiation in highly-selected patients with locally advanced lower rectal cancer could probably be an acceptable alternative to conventional radical surgery. However, this approach should be prospectively validated, and strict patient selection criteria should be used.