Adjuvant therapy for rectal cancer--the transatlantic view

The therapeutic and adverse effects of modified radiation fields for patients with rectal cancer

PURPOSE

To compare the therapeutic effect and complications of modified radiation fields (MRFs) with those of conventional pelvic radiation fields (CPRFs) for rectal cancer.

METHODS AND MATERIALS

From December 1996 to October 2009, a total of 160 patients with rectal carcinoma who received total mesorectal excision and postoperative radiotherapy were examined. Ninety-four patients were in the CPRFs group, and 66 were in the MRFs group. The dose was 50 Gy per 25 fractions in the initial plan.

RESULTS

The treatment volume and the volume of small bowel that received more than 15 Gy of the MRFs was smaller than that of the CPRFs (P < .001). The rates of local recurrence, overall survival, and disease-free survival were not statistically significant between the MRFs and CPRFs groups (P > .05). There was a statistical difference (P < .05) in the incidence of acute toxicity, which included serious complications in the lower digestive tract (grade ≥3). The completion rate for the initial radiotherapy plan was higher in the MRFs group than in the CPRFs group (P = .027).

CONCLUSIONS

Compared with CPRFs, MRFs manifested a lower incidence of complications and the same therapeutic effects. This finding will facilitate the clinical application of MRFs for patients with rectal cancer.

The clinicopathological features of colorectal mucinous adenocarcinoma and a therapeutic strategy for the disease

Background

The guidelines established by the National Comprehensive Cancer Network do not describe mucinous histology as a clinical factor that should influence the therapeutic algorithm. However, previous studies show conflicting results regarding the prognosis of colorectal mucinous adenocarcinoma. In this study, we described the clinicopathological features of mucinous adenocarcinoma in Japan, to identify optimal therapeutic strategies.

Methods

144 patients with mucinous and 2673 with non-mucinous adenocarcinomas who underwent primary resection in two major centers in Yokohama, Japan were retrospectively evaluated for clinicopathological features and treatment factors. A multivariate analysis for overall survival followed by the comparison of overall survival using Cox proportional hazard model were performed.

Results

Patients with mucinous adenocarcinoma had larger primary lesions, higher preoperative CEA levels, a deeper depth of invasion, higher rates of nodal and distant metastasis, and more metastatic sites. A multivariate analysis for overall survival revealed a mucinous histology to be an independent prognostic factor. In the subgroup analysis stratified by stage, Patients diagnosed as StageIII and IV disease had a worse survival in mucinous adenocarcinoma than non-mucinous, while survival did not differ significantly in patients diagnosed as Stage0-II disease. In StageIII, local recurrence in rectal cases and peritoneal dissemination were more frequently observed in patients with a mucinous histology.

Conclusions

Our study indentified that mucinous adenocarcinoma was associated with a worse survival compared with non-mucinous in patients with StageIII and IV disease. In rectal StageIII disease with mucinous histology, additional therapy to control local recurrence followed by surgical resection may be a strategical alternative. Further molecular investigations considering genetic features of mucinous histology will lead to drug development and better management of peritoneal metastasis

Lymph node status after neoadjuvant radiotherapy for rectal cancer is a biologic predictor of outcome

BACKGROUND

Lymph node (LN) status after surgery for rectal cancer is affected by preoperative radiotherapy. The purpose of this study was to perform a population-based evaluation of the impact of pathologic LN status (ypN) after neoadjuvant radiotherapy on survival.

METHODS

Patients undergoing radical resection for rectal adenocarcinoma were identified from the Surveillance Epidemiology and End Results registry (1991-2004). Patient characteristics, overall survival, and cancer-specific survival (CSS) by ypN stage after surgery and use of preoperative or postoperative radiotherapy were compared.

RESULTS

Of the 23,809 patients identified, 12,513 received preoperative (n = 5367) or postoperative (n = 7146) radiotherapy and resection. Preoperative patients were more likely to be younger (P < .001) and histopathologically free of detectable nodal metastasis (ypN0) than postoperative (51.8% vs 31.7%, P < .001). Median total numbers of LNs (6 vs 10) and positive LNs (2 vs 3) were lower among preoperative than postoperative (P < .001 for both). OS and CSS were similar among pN0 patients. However, on proportional hazards regression, ypN+ stage was associated with an increase in relative risk for death by 21% overall (hazard ratio [HR] = 1.21; 95% confidence interval 1.09-1.35, P < .001) and 23% cancer-specific (HR = 1.23; P = .001) for preoperative compared with postoperative.

CONCLUSIONS

Pathologic LN status after neoadjuvant radiotherapy for rectal cancer is a biologic marker of prognosis. Patients who are ypN+ after preoperative are a subgroup of LN positive patients with adverse outcome. These high-risk patients should be targeted for studies of novel multidisciplinary approaches, including expanded chemo- and biologic therapies.

Chemoradiotherapy and adjuvant chemotherapy for rectal cancer

Local recurrence is an important factor in determining the outcome of patients after surgery for rectal cancer, and various attempts have been made to reduce the local recurrence rate. Randomized controlled trials have shown that radiotherapy combined with total mesorectal excision can reduce the local recurrence rate in rectal cancer patients who undergo curative surgery. Chemoradiotherapy is more effective in achieving local control than radiotherapy alone, and preoperative chemoradiotherapy is superior to postoperative chemoradiotherapy in terms of adverse events. Recent advances have led to the identification of potential therapeutic targets such as epidermal growth factor receptor, vascular endothelial growth factor, and endothelial receptors. These new agents have been used in combination with conventional chemoradiotherapy, and higher pathological complete response rates have been reported for such combinations in comparison with conventional regimens. With regard to lateral node dissection, a recent study showed that postoperative chemoradiotherapy was more effective in reducing the local recurrence rate than lateral node dissection. As for adjuvant chemotherapy, one randomized controlled trial showed that patients who received uracil and tegafur as adjuvant therapy had significantly prolonged relapse-free survival times and overall survival times. As well, one metaanalysis has shown the efficacy of oral uracil-tegafur as adjuvant chemotherapy for rectal cancer.

Oncological outcome after local excision of rectal carcinomas

BACKGROUND

Local excision (LE) of T1 rectal cancer yields low recurrence rates. However, more frequent recurrences with unknown states of high-risk T1/T2 tumors are risk factors. The purpose of this study was to evaluate if, after LE, immediate reoperation is required, or awaiting salvage surgery is sufficient.

METHODS

150 T1 and 42 T2 tumors were treated by LE. Immediate reoperation was attempted for unfavorable pT1 (G3-4/L1/V1/R1/Rx/R < or =1 mm) and all pT2 tumors. Three groups were formed. Group A included low-risk pT1 tumors after complete (R0) LE; unfavorable pT1 and all T2 tumors were divided in groups B (immediate reoperation) and C (salvage surgery).

RESULTS

Groups A (n = 93) and B (n = 39) showed high tumor-free (TFS) and tumor-related survival (TRS) rates: group A 92% and 98%; group B 86% and 89%. In group C (n = 43), the TFS und TRS were significantly lower with 54% and 72%. Group A showed low recurrence rates and a wide range of International Union Against Cancer (UICC) stages. In group B, similarly low recurrence rates were found, but, in contrast, all recurrences were UICC IV. Group C had significantly higher recurrences rates and, in addition, two-thirds of these patients showed advanced UICC stages (III-IV).

CONCLUSIONS

LE of low-risk T1 tumors represents an adequate therapy. Immediate reoperation after LE of pT1 tumors with unfavorable histological finding or pT2 tumors can avoid local recurrences. Thereafter, high TFS rates can be expected in these patients, but metastases cannot be prevented and adjuvant measures are necessary. Awaiting recurrences as in group C leads to bad oncological outcomes with high recurrences and low survival rates.

Preoperative radiation response evaluated by 18-fluorodeoxyglucose positron emission tomography predicts survival in locally advanced rectal cancer

PURPOSE

This study focuses on the prognostic survival value of postirradiation metabolic activity in primary rectal cancer as measured with 18-fluorodeoxyglucose positron emission tomography.

METHODS

From July 1995 to March 2002, all 59 patients underwent two series of fluorodeoxyglucose positron emission tomography: one before preoperative radiation (standardized uptake values-1), and the other two to three weeks after radiation (standardized uptake values-2). Standardized uptake values-1 and standardized uptake values-2 correspond to before and after radiation, respectively.

RESULTS

In univariate analysis, the following emerged as significant prognostic variables: with or without residual tumor, pathologic differentiation, with or without recurrence, standardized uptake values-2, and with or without lymph node metastases. In multivariate analysis, residual tumor and standardized uptake values-2 were significant prognostic factors for survival. The median survival and the five-year overall survival rate comparing standardized uptake values-2 values <5 vs. >5 were 95 vs. 42 months and 70 vs. 44 percent, respectively (P = 0.042).

CONCLUSION

A significant survival benefit was observed in patients with low fluorodeoxyglucose uptake after preoperative radiotherapy in primary tumors of rectal cancer.

Local excision for ypT2 rectal cancer--much ado about something

BACKGROUND

The role of local excision for pT2 distal rectal cancer has been challenged because of the observation of high rates of lymph node metastases and local failure. However, neoadjuvant chemoradiation therapy (CRT) has led to increased local disease control and significant tumor downstaging, possibly decreasing rates of lymph node metastases. In this setting, a possible role for local excision of ypT2 has been suggested.

METHODS

A total of 401 patients with distal rectal cancer underwent neoadjuvant CRT. Tumor response assessment was performed after at least 8 weeks from CRT completion. One hundred and twelve patients with complete clinical response were not immediately operated on and were excluded from the study, and 289 patients with incomplete clinical response were managed by radical surgery. Patients with final pathological stage ypT2 were analyzed to determine the risk of unfavorable pathological features that could represent unacceptable risk for local failure after local excision.

RESULTS

Eighty-eight (30%) patients had ypT2 rectal cancer. Final ypT status was not associated with pretreatment radiological staging (p = 0.62). ypT status was significantly associated with the risk of lymph node metastases, risk of perineural and vascular invasion, and recurrence (p = 0.001). Lymph node metastases were present in 19% of patients with ypT2 rectal cancer. The risk of lymph node metastases in ypT2 was associated with the presence of perineural invasion (47% vs 4%; p = <0.001), vascular invasion (59% vs 6%; p < 0.001), and decreased mean interval CRT surgery (12 vs 18 weeks; p < 0.001), but not with mean tumor size (3.2 vs 3.1 cm; p = 0.8). Disease-free and overall survival rates were significantly better for patients with ypT2N0 (p = 0.02 and 0.006, respectively). Fifty-five (63%) patients with ypT2 had at least one unfavorable pathological feature for local excision (lymph node metastases, vascular or perineural invasion, mucinous type or tumor size >3 cm).

CONCLUSION

Lymph node metastases were present in 19% of patients with ypT2 and were significantly associated with poor overall and disease-free survival rates. The risk of lymph node metastases could not be predicted by radiological staging or tumor size. Radical surgery should be considered the standard treatment option for ypT2 rectal cancer after CRT.

Transanal endoscopic microsurgical excision of pT2 rectal cancer: results and possible indications

PURPOSE

In previous studies, local excision was predominantly established for "low-risk" pT1 rectal cancer. The results obtained with T2 tumors are unclear; recurrence rates of 0 to 67 percent were reported. This study was designed to determine the value of local excision for T2 rectal carcinomas, prognostic factors, and the need for reoperation.

METHODS

After local excision of 649 patients with rectal tumors, pT2 carcinoma was found in 44 patients. In general, immediate reoperation was recommended; however, 24 patients declined further surgery or were not reoperated because of comorbidities. The results were analyzed separately for local R0 resection of low-risk carcinomas and for prognostically unfavorable criteria (R1/RX/R < or = 1mm/G3-4/L1/V1). Reoperation was performed within four weeks. Recurrences also were divided by previous local R0 resection of low-risk tumors as well as by unfavorable results and were analyzed in a long-term, follow-up study. Patients with palliative therapy were excluded, and follow-up was obtained in 90 percent (20 transanal endoscopic microsurgical excision alone, 17 transanal endoscopic microsurgical excision and reoperation).

RESULTS

Local recurrence rates after local R0 resection alone of low-risk T2 carcinomas were 29 percent, whereas patients with unfavorable criteria developed recurrences in 50 percent. After immediate reoperation, the local recurrence risk in patients without lymph node filiae was significantly reduced to 7 percent.

CONCLUSIONS

Local R0 resection of low-risk pT2 carcinomas represents an inadequate therapy. In pT2N0M0 rectal carcinomas, the recurrence rate can be reduced through immediate reoperation to a level similar to primary radical surgery. An initial poor local resection result (R1/RX/R < or = 1 mm/G3-4/L1/V1) has no negative influence on further oncologic outcome.

Evaluation of safety of increased time interval between chemoradiation and resection for rectal cancer

BACKGROUND

Neoadjuvant chemoradiation is increasingly used for rectal cancer, with resection typically performed 6 weeks after completion of radiotherapy. We observed in our practice that further delay after radiotherapy led to increased downsizing. We performed this retrospective analysis to evaluate the safety of this approach.

METHODS

A retrospective review was performed of 48 patients with distal or mid-rectal cancer who were operated on 8 weeks or less after chemoradiation ended (group 1, n = 16), and more than 8 weeks later (group 2, n = 32). We looked at the effect of delaying surgery on intraoperative blood loss, operative and hospital duration, postoperative complications, readmissions, and mortality.

RESULTS

The median interval between radiation and operation was 7 weeks in group 1 and 11 weeks in group 2. There was no significant difference between the 2 groups in terms of intraoperative blood loss, postoperative complications, or readmissions. Length of operation and length of stay were slightly longer for group 2.

CONCLUSIONS

Delaying surgery after neoadjuvant treatment appears safe, with morbidity and mortality similar to that seen with surgery performed less than 8 weeks after chemoradiation.

Response to neoadjuvant therapy for rectal cancer: influence on long-term results

OBJECTIVE

Pre-operative treatment with chemoradiotherapy (CRT) seems to improve local control and overall survival in patients with rectal cancer. The aims of the study were to analyse the impact on overall, disease free and cancer related survival of tumour response to pre-operative CRT and to analyse the influence of the degree of response on long-terms results.

PATIENTS AND METHODS

Patients with a locally advanced rectal cancer, treated by pre-operative CRT were studied. A radical resection of the rectal tumour with mesorectal excision was performed within 6-8 weeks. Judged on the final TNM classification patients were considered responders when the tumour showed histologically a complete response, microscopic residual disease or a partial response. Non-responders were those in whom the extent of disease remained stable or progressed. Results Radical excision was performed in 103 patients, and a palliative resection in five. Forty-three patients underwent abdominoperineal resection and 65 anterior resection of the rectum. Seventy-one (65.7%) patients showed a response to CRT, while 37 (34.3%) did not. The overall local and distant recurrence rates were 6.8% and 21.3%. Tumour recurrence (P < 0.008) and disease free survival (P < 0.007) were significantly different in responders and nonresponders. Of the 71 responders, 16 had a pathological complete response, 27 had persisting microscopic disease and 28 had macroscopic residual disease. No differences in cancer specific outcome were observed in these groups.

CONCLUSION

Pathological response to pre-operative CRT is associated with improved tumour recurrence and disease-free survival rates. Any response to pre-operative CRT appears to improve outcomes as much as a complete response.

Pre-operative imaging of rectal cancer and its impact on surgical performance and treatment outcome

AIM

To discuss the ability of pre-operative MRI to have a beneficial effect on surgical performance and treatment outcome in patients with rectal cancer.

METHODS

A description on how MRI can be used as a tool so select patients for differentiated neoadjuvant treatment, how it can be used as an anatomical road map for the resection of locally advanced cases, and how it can serve as a tool for quality assurance of both the surgical procedure and overall patient management. As an illustration the proportion of microscopically complete resections of the period 1993-1997, when there was no routine pre-operative imaging, is compared to that of the period 1998-2002, when pre-operative MR imaging was standardized.

RESULTS

The proportion of R0 resections increased from 92.5 to 97% (p=0.08) and the proportion of resections with a lateral tumour free margin of >1mm increased from 84.4 to 92.1% (p=0.03). The incomplete resections in the first period were mainly due to inadequate surgical management of unsuspected advanced or bulky tumours, whereas in the second period insufficient consideration was given to extensive neoadjuvant treatment when the tumour was close to or invading the mesorectal fascia on MR.

CONCLUSIONS

There are good indications that in our setting pre-operative MR imaging, along with other improvements in rectal cancer management, had a beneficial effect on patient outcome. Audit and discussion of the incomplete resections can lead to an improved operative and perioperative management.

Effectiveness of gene expression profiling for response prediction of rectal adenocarcinomas to preoperative chemoradiotherapy

PURPOSE

There is a wide spectrum of tumor responsiveness of rectal adenocarcinomas to preoperative chemoradiotherapy ranging from complete response to complete resistance. This study aimed to investigate whether parallel gene expression profiling of the primary tumor can contribute to stratification of patients into groups of responders or nonresponders.

PATIENTS AND METHODS

Pretherapeutic biopsies from 30 locally advanced rectal carcinomas were analyzed for gene expression signatures using microarrays. All patients were participants of a phase III clinical trial (CAO/ARO/AIO-94, German Rectal Cancer Trial) and were randomized to receive a preoperative combined-modality therapy including fluorouracil and radiation. Class comparison was used to identify a set of genes that were differentially expressed between responders and nonresponders as measured by T level downsizing and histopathologic tumor regression grading.

RESULTS

In an initial set of 23 patients, responders and nonresponders showed significantly different expression levels for 54 genes (P < .001). The ability to predict response to therapy using gene expression profiles was rigorously evaluated using leave-one-out cross-validation. Tumor behavior was correctly predicted in 83% of patients (P = .02). Sensitivity (correct prediction of response) was 78%, and specificity (correct prediction of nonresponse) was 86%, with a positive and negative predictive value of 78% and 86%, respectively.

CONCLUSION

Our results suggest that pretherapeutic gene expression profiling may assist in response prediction of rectal adenocarcinomas to preoperative chemoradiotherapy. The implementation of gene expression profiles for treatment stratification and clinical management of cancer patients requires validation in large, independent studies, which are now warranted.

Preoperative chemoradiation with oral tegafur within a multidisciplinary therapeutic approach in patients with T3-4 rectal cancer

PURPOSE

The aim of this study was to evaluate the activity in terms of downstaging histologic patterns of residual tumor and clinical tolerance of a neoadjuvant chemoradiation program with oral tegafur for rectal cancer.

METHODS AND MATERIALS

From May 1998 to May 2001, 62 consecutive patients with cT(3-4) or cN(+) rectal cancer, or both, were treated with 45-50 Gy (1.8 Gy/day; 25 fractions) and oral tegafur 1200 mg/day. Surgery was performed 6 weeks after the completion of chemoradiation. All patients received a boost with intraoperative electron beam radiotherapy (IOERT) over the presacral space.

RESULTS

Grade 3-4 hematologic toxicity consisted on Grade 3 anemia in 1 patient. Nonhematologic toxicity was mild. Fifteen patients (23%) had Grade 3 dermatitis, 16 (25%) had Grade 3, and 2 (3%) had Grade 4 proctitis. The median dose of radiotherapy was 50.4 Gy. Surgery consisted on anterior resection in 38 patients (61%) and abdominoperineal amputation in 24 (39%). Five complete pathologic responses were observed (8%), and 29 patients (47%) had a minimal microscopic residual tumor (mic category). The total downstaging rate was 68%. With a median follow-up of 46 months, the pelvic control rate was 95%, disease-free survival 74.1%, and overall survival 76.5%.

CONCLUSIONS

Neoadjuvant chemoradiation with oral tegafur is feasible, well tolerated, and active, with the additional advantage of offering the convenience of oral chemotherapy.

[PET/CT for colorectal and hepatic tumors]

This contribution presents clinical and technical aspects of combining positron emission tomography (PET) and computed tomography (CT) for patients with colorectal tumors and characterization of unclear liver foci. In which manner and for which patients combined PET/CT is superior to PET or CT alone is also discussed. PET/CT can fulfil most prerequisites for imaging in pre- and postoperative management of patients with colorectal tumors and best meets the desire for optimal imaging procedures. Some of the disadvantages encountered in frequently employed CT can be overcome by the combination of PET and CT while increasing both sensitivity in detecting lesions and specificity in their characterization. Questions regarding treatment response offer an opportunity for devising novel study concepts and initiating research on new PET tracers. Although few publications are available, we are of the opinion that the combination of functional and anatomical imaging provided by PET/CT can improve both preoperative management and aftercare. To this end, however, optimum cooperation between practitioners of nuclear medicine and radiology is imperative.

The role of positron emission tomography in radiation treatment planning

We estimate that 30% to 40% of radiation treatment plans for cancer patients are changed when positron emission tomography (PET) scan findings are factored into the plan. The most frequent changes are upstaging of disease and the finding of new distant metastases. When a tumor demonstrates high tracer uptake, the PET scan has high accuracy in staging and in determining recurrent disease. However, the absence of tracer uptake cannot exclude residual dormant disease. Following radiation therapy, a PET scan should be delayed at least 6 weeks and preferably 3 to 4 months so that inflammation within the radiation field can dissipate. PET has resulted in changes in the gross tumor volume; however, the process remains subjective.