Local excision and postoperative radiation therapy for rectal adenocarcinoma

Radiation therapy for rectal cancer

Radiotherapy (RT) has remained an important pillar in the multi-modality management of rectal cancer. Adjuvant RT with concurrent chemotherapy (chemo-RT) was once the standard of care for locally advanced rectal cancer, but with time, that has now changed and neoadjuvant chemo-RT followed by total mesorectal excision (TME) surgery is the new standard. Alternatively, neoadjuvant RT alone remains an option and clinicians are tasked to choose between the two. In an era of personalised oncological management, it is unsurprising that the treatment for rectal cancer is following suit and upcoming trials are studying ways to improve outcomes and minimise toxicity for patients while tailoring treatments specific to each patient's tumour. We review the evolution of the role of RT in rectal cancer and look forward to what the future holds.

Transanal endoscopic microsurgery for rectal lesions in a specialist regional early rectal cancer centre: the Mersey experience

AIM

Organ-preserving local excision by transanal endoscopic microsurgery (TEM) for early rectal cancer offers significantly lower morbidity as compared to formal rectal cancer resection with acceptable outcomes. This study presents our 6-year experience of TEM for rectal lesions referred to a specialist early rectal cancer centre in the UK.

METHOD

Data were collected for all patients referred for TEM of suspected early rectal cancer to a regional specialist early rectal cancer multidisciplinary team (MDT) over a 6-year period.

RESULTS

One hundred and forty-one patients who underwent full-thickness TEM for suspected or confirmed early rectal cancer were included. Thirty patients were referred for TEM following incomplete endoscopic polypectomy. Final pathology was benign in 77 (54.6%) cases and malignant in 64 (45.4%). Of the 61 confirmed adenocarcinomas, TEM resections were pT0 in 17 (27.9%), pT1 in 32 (51.7%), pT2 in 11 (18.0%) and pT3 in 1 (1.6%). Thirty-eight of 61 patients (62.3%) had one or more poor histological prognostic features and these patients were offered further treatment. Twenty-three of 61 (37.7%) patients with rectal adenocarcinoma required no further treatment following TEM. Forty-three cases of rectal adenocarcinoma were available for establishing recurrence rates. Two of 43 patients (4.7%) developed a recurrence at a median follow-up of 28.7 months (12.1-66.5 months). The overall estimated 5-year overall survival rate was 87.9% and the disease-free survival rate was 82.9%.

CONCLUSION

Acceptable outcomes are possible for TEM surgery with appropriate patient selection, effective technique, expert histopathology, appropriate referral for adjuvant treatment and meticulous follow-up. This can be achieved through an early rectal cancer MDT in a dedicated specialist regional centre.

A multi-centred randomised trial of radical surgery versus adjuvant chemoradiotherapy after local excision for early rectal cancer

Background

Rectal cancer surgery is accompanied with high morbidity and poor long term functional outcome. Screening programs have shown a shift towards more early staged cancers. Patients with early rectal cancer can potentially benefit significantly from rectal preserving therapy. For the earliest stage cancers, local excision is sufficient when the risk of lymph node disease and subsequent recurrence is below 5 %. However, the majority of early cancers are associated with an intermediate risk of lymph node involvement (5–20 %) suggesting that local excision alone is not sufficient, while completion radical surgery, which is currently standard of care, could be a substantial overtreatment for this group of patients.

Methods/Study design

In this multicentre randomised trial, patients with an intermediate risk T1-2 rectal cancer, that has been locally excised using an endoluminal technique, will be randomized between adjuvant chemo-radiotherapylimited to the mesorectum and standard completion total mesorectal excision (TME). To strictly monitor the risk of locoregional recurrence in the experimental arm and enable early salvage surgery, there will be additional follow up with frequent MRI and endoscopy. The primary outcome of the study is three-year local recurrence rate. Secondary outcomes are morbidity, disease free and overall survival, stoma rate, functional outcomes, health related quality of life and costs. The design is a non inferiority study with a total sample size of 302 patients.

Discussion

The results of the TESAR trial will potentially demonstrate that adjuvant chemoradiotherapy is an oncological safe treatment option in patients who are confronted with the difficult clinical dilemma of a radically removed intermediate risk early rectal cancer by polypectomy or transanal surgery that is conventionally treated with subsequent radical surgery. Preserving the rectum using adjuvant radiotherapy is expected to significantly improve morbidity, function and quality of life if compared to completion TME surgery.

Trial registration

NCT02371304, registration date: February 2015

Meta-analysis of oncological outcomes after local excision of pT1-2 rectal cancer requiring adjuvant (chemo)radiotherapy or completion surgery

BACKGROUND

Completion total mesorectal excision (TME) is advised for high-risk early (pT1/pT2) rectal cancer following transanal removal. The main objective of this meta-analysis was to determine oncological outcomes of adjuvant (chemo)radiotherapy as a rectum-preserving alternative to completion TME.

METHODS

A literature search using PubMed, Embase and the Cochrane Library was performed in February 2015. Studies had to include at least ten patients with pT1/pT2 adenocarcinomas that were removed transanally and followed by either adjuvant chemoradiotherapy or completion surgery. A weighted average of the logit proportions was determined for the pooled analyses of subgroups according to treatment modality and pT category.

RESULTS

In total, 14 studies comprising 405 patients treated with adjuvant (chemo)radiotherapy and seven studies comprising 130 patients treated with completion TME were included. Owing to heterogeneity it was not possible to compare the two strategies directly. However, the weighted average local recurrence rate for locally excised pT1/pT2 rectal cancer treated with adjuvant (chemo)radiotherapy was 14 (95 per cent c.i. 11 to 18) per cent, and 7 (4 to 14) per cent following completion TME. The weighted averages for distance recurrence were 9 (6 to 14) and 9 (5 to 16) per cent respectively. Weighted averages for local recurrence rate after adjuvant chemo(radiotherapy) and completion TME for pT1 were 10 (4 to 21) and 6 (3 to 15) per cent respectively. Corresponding averages for pT2 were 15 (11 to 21) and 10 (4 to 22) per cent respectively.

CONCLUSION

A higher recurrence rate after transanal excision and adjuvant (chemo)radiotherapy must be balanced against the morbidity and mortality associated with mesorectal excision. A reasonable approach is close follow-up and salvage mesorectal surgery as needed.

Effectiveness of adjuvant radiotherapy after local excision of rectal cancer with deep submucosal invasion: a single-hospital, case-control analysis

BACKGROUND

The role of postoperative radiation therapy (RT) after local excision (LE) of deep submucosal invasive rectal cancer remains unclear. We evaluated the efficacy of adjuvant RT after LE of early rectal cancer with deep submucosal invasion.

METHODS

We screened 227 patients who underwent transanal excision or endoscopic removal of deep submucosal invasive rectal cancer between 1992 and 2012, of which 66 did not undergo radical surgery owing to the patient's preference or poor medical conditions. Of these, 35 (53 %) underwent LE alone (LE group) and 31 (47 %) received adjuvant RT after LE (LE + RT group). Nine patients in the RT group received concurrent adjuvant chemotherapy with 5-fluorouracil. Two independent pathologists reviewed histological data.

RESULTS

The mean age of patients in the LE + RT and LE groups was 59.5 ± 9.6 and 55.3 ± 11.2 years, respectively. The mean follow-up duration was 78.7 ± 66.7 months in the LE + RT group and 70.5 ± 45.7 months in the LE group. Cancer eventually recurred in six patients (9.1 %; two in the LE + RT group and four in the LE group). In five of these patients, recurrence occurred within 4 years after the initial treatment. The other patient, who was in the LE group, exhibited multiple lymph node metastases at the 116-month follow-up. Kaplan-Meier estimates of recurrence-free survival at 5 years after treatment were 96.8 % in the LE + RT group and 97 % in the LE group (P = 0.657).

CONCLUSION

RT after LE of early rectal cancer with deep submucosal invasion might not improve recurrence-free survival compared with LE alone.

Organ preservation in rectal cancer: have all questions been answered?

Improved treatment strategies have eliminated local control as the major problem in rectal cancer. With increasing awareness of long-term toxic effects in survivors of rectal cancer, organ-preservation strategies are becoming more popular. After chemoradiotherapy, both watchful waiting and local excision are used as possible alternatives for radical surgery. Although these seem attractive strategies, many issues about the safety of organ preservation remain. Additionally, radiotherapy strategies are mainly aimed at intermediate and high-risk rectal tumours, and adaptation of this standard practice for a completely new treatment indication has yet to start. This Review will discuss the options and problems of organ preservation, and address the research questions that need to be answered in the coming years, with a specific focus on radiotherapy.

Current controversies in neoadjuvant chemoradiation of rectal cancer

Total mesorectal excision with preoperative radiation and chemotherapy provide the lowest local recurrence rates for rectal cancer. Timing of surgery after preoperative chemoradiation is being increased to optimize tumor downstaging. In cases of complete clinical response from chemoradiation, permissive observation without resection is being investigated. Significant anorectal dysfunction results from low anterior resection and radiation. Good prognostic tumor characteristics are being investigated with the aim of selecting cases for whom preoperative radiation may be avoided. Preoperative and postoperative radiation provides improved local cancer control for superficial cancers removed by local excision.

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.

Depth of tumor invasion independently predicts lymph node metastasis in T2 rectal cancer

OBJECTIVE

The aim of this study was to identify risk factors of lymph node metastasis (LNM) for T2 rectal cancer.

METHODS

From a prospectively maintained single-institution database, we identified 346 consecutive pT2 rectal cancers treated with total mesorectal excision from 1998 to 2009. Univariate and multivariate analyses were performed to identify risk factors associated with overall and intermediate/apical LNM. The incidence of overall and intermediate/apical LNM was analyzed by tree analysis.

RESULTS

Age, tumor location, pathological features, and depth of invasion were independent predictors for overall LNM. Tumor location, pathological features, and depth of invasion were independent predictors for intermediate/apical LNM. Tree analysis showed that the incidence of LNM was 7.7% for upper rectal cancer with favorable pathological features, and 3.4% for mid/lower rectal cancer without other identified risk factors. The incidence of intermediate/apical LNM was 5.7% for superficial T2 rectal cancer with favorable pathological features, and 3.1% for deep T2 rectal cancer locating in upper rectum with favorable pathological features.

CONCLUSIONS

Depth of invasion is an independent predictor for LNM in T2 rectal cancer. Using tree analysis, we identified a subset of patients with low risk of LNM who may be candidates of local excision.

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.

Is total mesorectal excision always necessary for T1-T2 lower rectal cancer?

BACKGROUND

The goal of this multicenter study was to clarify the determinants of local excision for patients with T1-T2 lower rectal cancer.

METHODS

Data from 567 consecutive patients who underwent radical resection for T1-T2 lower rectal cancer at 12 institutions between 1991 and 1998 were reviewed. Rates of lymph node metastasis were investigated using a tree analysis, which was hierarchized using independent risk factors for nodal involvement.

RESULTS

The independent risk factors for lymph node metastasis were female gender, depth of tumor invasion, histology other than well-differentiated adenocarcinoma, and lymphatic invasion. According to the first three parameters that can be obtained preoperatively, only 0.99% of the patients without risk factors had lymph node metastasis. On the other hand, even if the lower rectal cancer was at stage T1, women with histological types other than well-differentiated adenocarcinoma had an approximately 30% probability of having lymph node metastasis. Lymphatic invasion was most useful to predict nodal involvement among patients with T2 lower rectal cancer. The rates of lymph node metastasis in T2 patients with and without lymphatic invasion were 32.9% and 9.1%, respectively.

CONCLUSIONS

Gender is one of the most important predictors for lymph node metastasis in patients with early distal rectal cancer. Three parameters, including depth of tumor invasion, histology, and gender, are useful determinants for local excision. Additional studies are required to establish the minimum optimal treatment for T2 lower rectal cancer.

Local excision of distal rectal cancer: an update of cancer and leukemia group B 8984

PURPOSE

The efficacy of local excision in the treatment of some early-stage distal rectal cancers is still being debated, because few high-quality, long-term prospective data on outcomes are available.

METHODS

Fifty-nine patients with T1 lesions were treated with local excision alone, whereas 51 patients with T2 lesions received external beam irradiation (5,400 cGY) and 5-fluorouracil (500 mg/m(2) intravenously Days 1-3, Days 29-31) after local excision. Kaplan-Meier curves were used to estimate the primary outcomes. The log-rank test and Cox's proportional hazards model were used to compare subgroups relative to these outcomes.

RESULTS

With a median follow-up of 7.1 (range, 2.1-11.4) years, ten-year rates of overall survival were 84 percent for patients with T1 and 66 percent for T2 rectal cancer. Disease-free survival was 75 percent for T1 and 64 percent for T2 disease. Local recurrence rates for patients with T1 and T2 lesions were 8 and 18 percent, respectively, and rates of distant metastases were 5 percent for T1 and 12 percent for T2 lesions. T stage was a statistically significant predictor of overall survival (P = 0.04) and approached statistical significance as a predictor of disease-free survival (P = 0.07).

CONCLUSIONS

Local excision alone for T1 rectal adenocarcinomas is associated with low recurrence and good survival rates that remain durable with long-term follow-up. T2 lesions treated via local excision and adjuvant therapy are associated with higher recurrence rates.

Controversies of total mesorectal excision for rectal cancer in elderly patients

The cornerstone of treatment for rectal cancer is resectional treatment according to the principles of total mesorectal excision (TME). However, population-based registries show that improvements in outcome after resectional treatment occur mainly in younger patients. Furthermore, 6-month postoperative mortality is significantly increased in elderly patients (> or = 75 years of age) compared with younger patients (< 75 years of age). Several confounding factors, such as treatment-related complications and comorbidity, are thought to be responsible for these disappointing findings. Thus, major resectional treatment is not advantageous for all older patients with rectal cancer. However, the Dutch TME trial showed a good response to a short course of neoadjuvant radiotherapy in elderly patients. Biological responses to cancer treatment seem to change with age, and, therefore, individualised cancer treatments should be used that take into account the heterogeneity of ageing. For elderly patients who retain a good physical and mental condition, treatment that is given to younger patients is deemed appropriate, whereas for those with diminished physiological reserves and comorbid conditions, alternative treatments that keep surgical trauma to a minimum and optimise the use of radiotherapy might be more suitable.

Imaging and management of rectal cancer

Local staging and management of rectal cancer has evolved during the past decade. Imaging modalities used for staging rectal cancer include CT, endoscopic ultrasound, pelvic phased-array coil MRI, endorectal MRI, and PET. Each modality has its strengths and limitations. Evidence supports the use of both endoscopic ultrasound and CT in staging rectal cancer. MRI is the only reliable tool for determining the status of the circumferential resection margin, which is important for the assessment of the risk of local recurrence.

Long-term oncologic results of patients with distal rectal cancer treated by local excision with or without adjuvant treatment

AIM

The aim of this study is to review long-term oncologic results of local excision (LE) and to investigate the validity and feasibility of LE as a treatment option for distal rectal cancer.

MATERIALS AND METHODS

Seventy-six patients who underwent LE for distal rectal adenocarcinoma with curative intent from 1991 to 2000 at Severance Hospital Yonsei University Medical Center, Seoul, Korea were enrolled in this study.

RESULTS

Preoperative transrectal ultrasonography revealed 3 cases of uT0, 55 cases of uT1 and 18 cases of uT2. Postoperative pathologic examination revealed 10 cases of pT0 (where no residual cancer cells remained), 11 cases of pTis, 37 cases of pT1, 16 cases of pT2, and 2 cases of pT3. Eleven out of 37 patients with pT1 tumors received adjuvant radiation therapy. Among 16 patients with pT2 tumor, 7 undertook salvage operation and 8 received adjuvant therapy. The median follow-up period was 84.9 months. Local recurrence was observed in six patients. The 5-year local recurrence-free survival rate (LFS) was 89.4% in the pT1 group and 75.0% in the pT2 group (p = 0.012). Among the patients with pT1 cancer, those who received adjuvant radiation therapy demonstrated a 5-year LFS of 100%, compared to those who did not, 76.0% (p = 0.038).

CONCLUSION

Our results imply a potential role of LE and adjuvant radiation as an option for the treatment of distal rectal cancer, and that even for pT1 carcinoma, LE alone might not be a valid modality.

Surgical management of rectal cancer

Rectal cancer affects more than 40,000 people in the United States annually. Despite recent advances in radiation and chemotherapy, surgical resection remains an integral part of curative therapy for this disease. Although rectal cancer is thought to be biologically similar to colon cancer, the anatomic complexity of the pelvis makes therapy for this disease considerably more complicated. Local recurrence is also a greater concern in rectal cancer than in colon cancer. The choice of surgical therapy depends on the location of the tumor, depth of rectal wall invasion, and clinical stage. Surgical options include local excision (transanal excision and transanal endoscopic microsurgery) and radical resection (low anterior resection, extended low anterior resection with coloanal anastomosis, abdominoperineal resection [APR], and pelvic exenteration). Technical advances such as transanal endoscopic microsurgery and laparoscopy also are changing the surgical approach to rectal tumors. Finally, chemotherapy and radiation are now frequently recommended in conjunction with surgical therapy. This article reviews the current surgical approach to treating patients with rectal cancer.

A current perspective on local excision of rectal cancer

Local excision of rectal cancer is appealing because of its technical ease and excellent functional results, but concern over inadequate pathologic staging and inferior treatment outcomes when compared with radical surgery remain a major hurdle for its widespread use. Local failure rates in modern series for local excision are 4%-18% for T1 rectal cancers and 22%-67% for T2 cancers, and cancer cure rates are only 70%-80%. In addition, data from the past decade suggest that preoperative staging with endorectal ultrasound, use of postoperative adjuvant chemotherapy/radiation therapy, and aggressive salvage surgery have not been reliable methods of limiting local tumor recurrence or improving long-term cure rates. At present, highly stringent criteria for patient selection are recommended, yet such stringency decreases the utility of the procedure. What are needed are new approaches to an old problem. Novel strategies under evaluation include enhanced imaging modalities for lymph node metastases, neoadjuvant chemotherapy/radiation therapy, and more liberal use of immediate salvage resection for high-risk pathologic features. Molecular profiling of tumors with genetic markers and better integration of traditional and gene-targeted systemic therapy are promising approaches for the future. This review of the literature evaluates the recent successes and failures of local excision of rectal cancer and provides a current perspective on the expanded use of local excision without compromising care.

Treatment of T1–T2 rectal tumors by contact therapy and interstitial brachytherapy

BACKGROUND AND PURPOSE

We retrospectively analysed our experience of contact therapy alone and/or combined with interstitial brachytherapy as exclusive treatment of low lying rectal tumours.

PATIENTS AND METHODS

From 1971 to 2001, 124 patients (103 adenocarcinomas, 21 villous tumours) were treated by contact therapy alone or combined with interstitial brachytherapy. All patients were staged according to the Dijon classification. The average size of the lesions was 2.4 cm (max 7 cm), clinical aspect was polypoïd in 75% of the cases, flat in 17%. Sixty four patients received contact therapy in three fractions and 44 patients received four fractions, for an average delivered dose of 95 Gy. Interstitial brachytherapy boost delivered 24 Gy on a reference isodose of 55 cGy/h in 10 patients.

RESULTS

The local control was 83% for T1 and 38% for T2 tumours (p=0.004). For mobile tumours, the local control rate is 76%, significantly higher than for tumours with impaired mobility (55%, P=0.03). Thirty-nine patients experienced a local failure (31%). For patients amenable to surgery, a Miles procedure was performed in 25 patients. Ultimate local control rate is 93% for T1, 69% for T2 (P<0.05), 15 patients failed despite treatment for local recurrence (15%). No significant differences were observed in a comparison of adenocarcinoma and villous tumours according to initial and ultimate local control. The mean disease free survival rate for the whole population is 66 months. The 5-year disease free survival for T1a and T1b is, respectively, 82 and 78%, 40 and 25% for T2a and T2b, respectively. The overall 5-year survival for the whole group is 62.4%. At the end of the treatment, 75% of the patients described a very good sphincter function. No deleterious effect on continence was reported during the follow-up.

CONCLUSIONS

The control rate for T1 rectal cancer treated with contact therapy with or without brachytherapy is comparable to surgical series. The sphincter was preserved in 80% of the patients. Radiotherapy remains an efficient and cheap alternative to surgery, mainly for old and fragile patients, or refusing colostomy. The results of these approaches for tumors larger than 3 cm (T2) are not satisfactory. For patients not amenable to surgery, external beam radiation therapy and/or combined modality with chemoradiation should be discussed to increase the loco-regional control rate. A careful selection of patients based on rectal examination and trans-rectal ultrasound could select more accurately patients amenable to such an approach.