Adjuvant therapy for colorectal cancer: present and future perspectives

Survival Analysis of Patients with Colorectal Cancer Undergoing Combined Treatment: A Retrospective Cohort Study

BACKGROUND

If colorectal cancer (CRC) is diagnosed in the early stages, the patients will have higher survival rates. Although some other factors might affect the survival rate, the type of treatment available based on existing health and therapeutic facilities is extremely important as well. Accordingly, this study aimed to explore the best type of treatment for CRC patients.

STUDY DESIGN

This study employed a retrospective population-based cohort design.

METHODS

The data of 335 patients with CRC in Kurdistan province were collected through a population-based cancer registry system from March 1, 2009 to 2014. Demographic and clinical-pathologic data of the patients were gathered through their medical records, pathology reports, and reference to patients' homes. The survival rate was calculated using the Kaplan-Meier curve, log-rank test, and univariate and multivariate Cox regression. The data were analyzed using Stata 14 software.

RESULTS

In this study, the mean age±standard deviation at diagnosis was 61.7± 1.05 in men and 60.5± 1.12 in women, respectively, and 203 (60.5%) patients were males. There was less mortality rate among the patients who received both surgical and chemotherapy treatments compared to those who did not receive any treatment (Hazard ratio [HR]=0.57, 95% CI: 0.24-0.93).

CONCLUSION

When CRC patients are treated using both surgical and chemotherapy treatments, they will exhibit a higher survival rate. Therefore, it is suggested to use both treatments for CRC patients.

Genetic polymorphisms in 5-Fluorouracil-related enzymes predict pathologic response after neoadjuvant chemoradiation for rectal cancer

BACKGROUND

Many patients with rectal cancer undergo preoperative neoadjuvant chemoradiation, with approximately 70% exhibiting pathologic downstaging in response to treatment. Currently, there is no accurate test to predict patients who are likely to be complete responders to therapy. 5-Fluorouracil is used regularly in the neoadjuvant treatment of rectal cancer. Genetic polymorphisms affect the activity of thymidylate synthase, an enzyme involved in 5-Fluorouracil metabolism, which may account for observed differences in response to neoadjuvant treatment between patients. Detection of genetic polymorphisms might identify patients who are likely to have a complete response to neoadjuvant therapy and perhaps allow them to avoid operation.

METHODS

DNA was isolated from whole blood taken from patients with newly diagnosed rectal cancer who received neoadjuvant therapy (n = 50). Response to therapy was calculated with a tumor regression score based on histology from the time of operation. Polymerase chain reaction was performed targeting the promoter region of thymidylate synthase. Polymerase chain reaction products were separated using electrophoresis to determine whether patients were homozygous for a double-tandem repeat (2R), a triple-tandem repeat (3R), or were heterozygous (2R/3R). A single nucleotide polymorphism, 3G or 3C, also may be present in the second repeat unit of the triple-tandem repeat allele. Restriction fragment length polymorphism assays were performed in patients with at least one 3R allele using HaeIII.

RESULTS

Patients with at least 1 thymidylate synthase 3G allele were more likely to have a complete or partial pathologic response to 5-Fluorouracil neoadjuvant therapy (odds ratio 10.4; 95% confidence interval, 1.3-81.6; P = .01) than those without at least one 3G allele.

CONCLUSION

Identification of rectal cancer patients with specific genetic polymorphisms in enzymes involved in 5-Fluorouracil metabolism seems to predict the likelihood of complete or partial pathologic response to preoperative neoadjuvant therapy.

Unsupervised analyses reveal molecular subtypes associated to prognosis and response to therapy in colorectal cancer

SUMMARY

Colorectal cancer (CRC) tumors are highly heterogeneous at a molecular level. Recent studies have proposed molecular classifications of intrinsic CRC molecular subtypes identified after applying unsupervised clustering methods to genome-wide data. Those subtypes, characterized by their distinct clinical and biological features, provide new insight about the complexity of CRC. A common finding shared by almost all analyses was the identification of microsatellite instable tumors as an independent cluster, which is associated to better prognosis. Clusters of tumors characterized by a high stromal component exhibited a poor outcome. Moreover, some of the clusters were associated with response to standard chemotherapy or targeted agents. Regarding biological functions underlying tumor subtypes, recurrent ones across different studies were WNT pathway activation, epithelial-to-mesenchymal transition or cancer stem cell-like phenotype. Now, the challenge is to translate these findings into a comprehensive CRC classification and characterization helpful for patients’ stratification and better clinical management.

Gene expression differences between colon and rectum tumors

PURPOSE

Colorectal cancer studies typically include both colon and rectum tumors as a common entity, though this assumption is controversial and only minor differences have been reported at the molecular and epidemiologic level. We conducted a molecular study based on gene expression data of tumors from colon and rectum to assess the degree of similarity between these cancer sites at transcriptomic level.

EXPERIMENTAL DESIGN

A pooled analysis of 460 colon tumors and 100 rectum tumors from four data sets belonging to three independent studies was conducted. Microsatellite instable tumors were excluded as these are known to have a different expression profile and have a preferential proximal colon location. Expression differences were assessed with linear models, and significant genes were identified using adjustment for multiple comparisons.

RESULTS

Minor differences at a gene expression level were found between tumors arising in the proximal colon, distal colon, or rectum. Only several HOX genes were found to be associated with tumor location. More differences were found between proximal and distal colon than between distal colon and rectum.

CONCLUSIONS

Microsatellite stable colorectal cancers do not show major transcriptomic differences for tumors arising in the colon or rectum. The small but consistent differences observed are largely driven by the HOX genes. These results may have important implications in the design and interpretation of studies in colorectal cancer.

Linear and branched glyco-lipopeptide vaccines follow distinct cross-presentation pathways and generate different magnitudes of antitumor immunity

BACKGROUND

Glyco-lipopeptides, a form of lipid-tailed glyco-peptide, are currently under intense investigation as B- and T-cell based vaccine immunotherapy for many cancers. However, the cellular and molecular mechanisms of glyco-lipopeptides (GLPs) immunogenicity and the position of the lipid moiety on immunogenicity and protective efficacy of GLPs remain to be determined.

METHODS/PRINCIPAL FINDINGS

We have constructed two structural analogues of HER-2 glyco-lipopeptide (HER-GLP) by synthesizing a chimeric peptide made of one universal CD4(+) epitope (PADRE) and one HER-2 CD8(+) T-cell epitope (HER(420-429)). The C-terminal end of the resulting CD4-CD8 chimeric peptide was coupled to a tumor carbohydrate B-cell epitope, based on a regioselectively addressable functionalized templates (RAFT), made of four alpha-GalNAc molecules. The resulting HER glyco-peptide (HER-GP) was then linked to a palmitic acid moiety, attached either at the N-terminal end (linear HER-GLP-1) or in the middle between the CD4+ and CD8+ T cell epitopes (branched HER-GLP-2). We have investigated the uptake, processing and cross-presentation pathways of the two HER-GLP vaccine constructs, and assessed whether the position of linkage of the lipid moiety would affect the B- and T-cell immunogenicity and protective efficacy. Immunization of mice revealed that the linear HER-GLP-1 induced a stronger and longer lasting HER(420-429)-specific IFN-gamma producing CD8(+) T cell response, while the branched HER-GLP-2 induced a stronger tumor-specific IgG response. The linear HER-GLP-1 was taken up easily by dendritic cells (DCs), induced stronger DCs maturation and produced a potent TLR- 2-dependent T-cell activation. The linear and branched HER-GLP molecules appeared to follow two different cross-presentation pathways. While regression of established tumors was induced by both linear HER-GLP-1 and branched HER-GLP-2, the inhibition of tumor growth was significantly higher in HER-GLP-1 immunized mice (p<0.005).

SIGNIFICANCE

These findings have important implications for the development of effective GLP based immunotherapeutic strategies against cancers.

Colorectal cancer, one entity or three

Understanding of the mechanism of colorectal carcinogenesis has been gaining momentum for some years on account of its high incidence and impact on the lives of individuals affected. Different genetic abnormalities have been found in colorectal cancers from different sites. For example, proximal colon cancer is usually related to the nucleotide instability pathway, as microsatellite instability (MSI). However, distal colon cancer is usually associated with specific chromosomal instability (CIN). The development of cancer at the rectum, though similar to that at the colon, displays its own unique features. These differences might be partially attributed to different embryological development and physiological circumstances. Environmental factors such as diet and alcohol intake also differ in their role in the development of tumors in the three segments, proximal colon, distal colon, and rectum. "Proximal shift" of colon cancer has been known for some time, and survival rates of colorectal cancer are higher when rectal cancers are excluded, both of which emphasize the three different segments of colorectal cancer and their different properties. Meanwhile, colonic and rectal cancers are distinctive therapeutic entities. The concept of three entities of colorectal cancer may be important in designing clinical trails or therapeutic strategies. However, the dispute about the inconsistency of data concerning the site-specific mechanism of colorectal carcinoma does exist, and more evidence about molecular events of carcinogenesis and targeted therapy needs to be collected to definitely confirm the conception.

Antitumor activity of a self-adjuvanting glyco-lipopeptide vaccine bearing B cell, CD4+ and CD8+ T cell epitopes

Molecularly defined synthetic vaccines capable of inducing both antibodies and cellular anti-tumor immune responses, in a manner compatible with human delivery, are limited. Few molecules achieve this target without utilizing external immuno-adjuvants. In this study, we explored a self-adjuvanting glyco-lipopeptide (GLP) as a platform for cancer vaccines using as a model MO5, an OVA-expressing mouse B16 melanoma. A prototype B and T cell epitope-based GLP molecule was constructed by synthesizing a chimeric peptide made of a CD8(+) T cell epitope, from ovalbumin (OVA(257-264)) and an universal CD4(+) T helper (Th) epitope (PADRE). The resulting CTL-Th peptide backbones was coupled to a carbohydrate B cell epitope based on a regioselectively addressable functionalized templates (RAFT), made of four alpha-GalNAc molecules at C-terminal. The N terminus of the resulting glycopeptides (GP) was then linked to a palmitic acid moiety (PAM), obviating the need for potentially toxic external immuno-adjuvants. The final prototype OVA-GLP molecule, delivered in adjuvant-free PBS, in mice induced: (1) robust RAFT-specific IgG/IgM that recognized tumor cell lines; (2) local and systemic OVA(257-264)-specific IFN-gamma producing CD8(+) T cells; (3) PADRE-specific CD4(+) T cells; (4) OVA-GLP vaccination elicited a reduction of tumor size in mice inoculated with syngeneic murine MO5 carcinoma cells and a protection from lethal carcinoma cell challenge; (5) finally, OVA-GLP immunization significantly inhibited the growth of pre-established MO5 tumors. Our results suggest self-adjuvanting glyco-lipopeptide molecules as a platform for B Cell, CD4(+), and CD8(+) T cell epitopes-based immunotherapeutic cancer vaccines.

The application of sentinel lymph node mapping in colon cancer

Lymph node status is the most important prognostic factor for colorectal carcinoma. Complete lymph node dissection has historically been an integral part of the surgical treatment of these diseases. Sentinel lymph node mapping is a newer technology that allows selective removal of the first node draining a tumor. Sentinel node mapping is well accepted for the management of breast carcinoma and cutaneous melanoma, and has resulted in reduced morbidity without adversely affecting survival. Sentinel node mapping is currently being investigated for treatment of colorectal cancers. Recent studies show promise for incorporating the sentinel node mapping technique for treatment of several gastrointestinal malignancies.

What factors affect lymph node yield in surgery for rectal cancer?

OBJECTIVE

The detection of lymph node metastases is of vital importance in patients undergoing excisional surgery for rectal cancer as it provides important prognostic information and facilitates decision-making with regards to adjuvant therapy. It has been suggested that patients in whom only a small number of nodes are present in the excised specimen have a worse prognosis, presumably due to inadequate lymphadenectomy and consequent understaging of the disease. The aim of this study was to determine which factors affect the yield of lymph nodes.

METHODS

This was a retrospective study of patients who had undergone a resection for histologically proven adenocarcinoma of the rectum. The total number of lymph nodes identified in the excised specimen was recorded in each case. A multivariate analysis was performed to ascertain whether this number was significantly influenced by any of several variables.

RESULTS

A total of 167 patients were studied (M:F ratio 107 : 60, median age 70 years). The median number of lymph nodes contained within the resected specimen was 16 (interquartile range 10-21). On univariate analysis a significantly higher yield of lymph nodes was obtained with tumours in the middle third of the rectum (P=0.007), larger tumours (P < 0.001), more locally advanced tumours according to both pT staging (P=0.001) and Dukes' staging (P=0.020), an increased number of involved nodes (P=0.003) and examination by a specialist histopathologist (P=0.003). On multivariate analysis the only significant variables were tumour size (P=0.021), number of positive nodes (P=0.007) and histopathologist (P=0.021).

CONCLUSIONS

The number of lymph nodes identified within the excised specimen in patients undergoing resection of a rectal cancer positively correlates with the size of the tumour and is also dependent on the examining histopathologist. In addition, in node-positive patients the number of involved nodes increases with increasing lymph node yield.

Curative treatment of gastric cancer: towards a multidisciplinary approach?

Despite marked decreases in incidence over the last century, particularly in developed countries, gastric cancer is still the second-most common tumor worldwide. Surgery remains the gold standard for the cure of locoregional disease. However, in most countries, the diagnosis is made at an advanced stage, and the 5-year survival for surgically resectable disease stays far below 50%. The efficacy of chemotherapy and/or radiation therapy in addition to surgery has been actively studied over the last 30 years. Unfortunately, with few exceptions, most studies of adjuvant therapy in gastric cancer have given deceiving results. The purpose of this review is to address the reasons for our failure to objectivate an improvement in the cure of gastric cancer with adjuvant treatment in most trials, and to consider potential solutions. The low efficacy of chemotherapy regimens available up to now may have hampered our progress. In addition, many previous studies suffered limitations of design or methodology (e.g. low accrual, inadequate disease stage selection, inadequate surgical treatment) that may have obscured a treatment effect. Furthermore, the reduced treatment tolerance of post-gastrectomy patients, perhaps due to their poor nutritional status, results in decreased or delayed adjuvant systemic therapy, with potential adverse consequences in its efficacy. Among potential solutions, the arrival of new drugs, taxanes and topoisomerase I inhibitors in particular, which have shown encouraging results in metastatic disease, may increase the impact of chemotherapy in a multidisciplinary treatment approach. Pre-treatment with chemotherapy and/or radiation therapy prior to surgery may also be advantageous, averting the problems associated with post-surgical treatment. Such an approach has been shown to be feasible in phase II studies, and is relatively well tolerated by patients. Several carefully designed randomized phase III trials are underway to answer this question.

Adenoviral-mediated transfer of Escherichia coli uracil phosphoribosyltransferase (UPRT) gene to modulate the sensitivity of the human colon cancer cells to 5-fluorouracil

5-Fluorouracil (5-FU) has been used as a chemotherapeutic drug for colorectal cancer. Escherichia coli uracil phosphoribosyltransferase (UPRT), a pyrimidine salvage enzyme, converts 5-FU into 5-fluorouridine monophosphate (5-FUMP) at the initial step of 5-FU activation. We investigated the effects of adenoviral-mediated transfer of the E. coli UPRT gene into human colon cancer cells on 5-FU metabolism and 5-FU chemosensitivity. Three cell lines were used (HT29, KM12 and SW1116). The intracellular levels of 5-fluorodeoxyuridine monophosphate (5-FdUMP) and 5-FU incorporated into RNA after 5-FU treatment in cells infected with adenovirus containing the UPRT gene (AdCA-UPRT) were significantly higher than those of non-infected cells. This was accompanied by marked inhibition of thymidylate synthase (TS) in all cell lines. Furthermore, HT29, KM12 and SW1116 infected with AdCA-UPRT were, respectively, 13.1-, 30.2- and 70.5-fold more sensitive to 5-FU than non-infected cells. Most importantly, treatment with AdCA-UPRT and 5-FU effectively inhibited the growth of HT29-xenografted subcutaneous tumours in nude mice. Therefore, AdCA-UPRT/5-FU treatment had the potential to enhance the actions of 5-FU at both the DNA and RNA levels. Treatment augmented the sensitivity of human colon cancer cells to 5-FU both in vitro and in vivo. We conclude that adenoviral-mediated transfer of the E. coli UPRT gene into colon cancer cells can achieve biochemical modulation of 5-FU and this provides a new approach in the treatment of colorectal cancer.

Improved results in rectal cancer surgery-an effect of specialization?

OBJECTIVE

The surgeon- and hospital-related variability in outcome after surgery for rectal cancer has been much debated. This study comprises a 6-year period of rectal cancer treatment at a single surgical Institution, where substantial changes in the treatment strategy of rectal cancer were implemented.

PATIENTS AND METHODS

Prospective and retrospective analysis of complications, stoma frequency, local recurrence rate and survival in 252 patients operated on for rectal cancer before (1990-1992) and after (1994-1996) the creation of a specialized rectal cancer team.

RESULTS

Specialization led to a significant decrease both in the need of permanent stomas (52% before vs 33% after specialization; P=0.02) and in the frequency of local recurrence (18% vs 3%; P=0.002). No increase in the frequency of post-operative complications, re-operations or, specifically, pelvic sepsis could be detected in the later period, although more extensive surgery was used and the anastomotic level decreased from 8 to 4 cm (P < 0.001). Cancer-specific survival at 2 years after operation was significantly higher in patients operated in 1994-1996 than in those operated 1990-1992 (P=0.006).

CONCLUSION

Concentrating the care of patients with rectal cancer to a specialized team seems to improve quality and outcome.

Preoperative plasma plasminogen activator inhibitor type-1 and serum C-reactive protein levels in patients with colorectal cancer. The RANX05 Colorectal Cancer Study Group

BACKGROUND

Preoperative plasma plasminogen activator inhibitor-1 (PAI-1) is a prognostic variable in patients with colorectal cancer. It has been suggested, however, that plasma PAI-1 is a nonspecific prognostic parameter similar to the acute-phase reactant C-reactive protein (CRP). In the present study we analyzed the association between plasma PAI-1 and serum CRP in patients scheduled for elective resection of colorectal cancer. In addition, the prognostic value of PAI-1 and CRP was studied in this patient cohort.

METHODS

PAI-1 and CRP were analyzed in citrated plasma and serum, respectively, obtained preoperatively from 594 patients. Patients who required preoperative blood transfusion received SAGM blood, in which soluble PAI-1 is not present. None of the patients received pre- or postoperative adjuvant chemotherapy, and all were followed in the outpatient clinic for at least 5 years or until death. The association of PAI-1 and CRP, respectively, with survival was tested using the median value of PAI-1 and the upper normal limit for CRP. Analyses were performed by inclusion of all patients, and in the subgroup of patients, who underwent curative resection.

RESULTS

The median follow-up period was 6.8 (5.4-7.9) years. The median value of plasma PAI-1 was 35.8 ng/ml, and values greater than 94 nmol/L identified patients with increased CRP levels. Comparison of the molecules showed that PAI-1 was weakly correlated with CRP (r = .26; P <.0001). Both molecules showed a Dukes independent distribution. In univariate survival analyses high levels of PAI-1 were found associated with poor prognosis and low levels with good prognosis (P = .02, HR: 1.3). Similarly, high levels of CRP were found associated with poor prognosis and low levels with good prognosis (P <.0001, HR: 1.9). In a multivariate statistical analysis including Dukes classification, gender, age, tumor location, perioperative blood transfusion, PAI-1 and CRP, plasma PAI-1 was a dependent prognostic variable, while serum CRP (P <.0001; HR: 1.4; 95% CI: 1.3-1.5) was found to be a Dukes independent prognostic variable. Similar analyses, excluding patients with Dukes' D disease showed serum CRP to be an independent prognostic variable (P <.0001; HR: 1.3: 95% CI: 1.2-1.5).

CONCLUSIONS

This study did not show a strong correlation between plasma PAI-1 and serum CRP in patients with colorectal cancer. Serum CRP was found to be a Dukes independent prognostic variable in this patient cohort, and was found to identify a subgroup of curatively resected patients at risk for short survival.

Large-field, external beam irradiation as a surgical adjuvant for node-positive colon carcinoma: an Eastern Cooperative Oncology Group Pilot Study (PA285)

The Eastern Cooperative Oncology Group (ECOG) PA-285 study was designed as a pilot study to evaluate the effect of large-field, external beam abdominal irradiation as an adjuvant treatment for resectable stage C1 to C2 colon cancer. Eligible patients received 45 Gy directed to the tumor bed and periaortic lymph nodes, as well as 30 Gy to the liver. Patients were followed up for time to recurrence and for survival. Fourteen patients were enrolled. One elected not to have radiation after surgery; one died of acute hepatic radiation toxicity after a major deviation from protocol. Of the 12 remaining patients, seven survived longer than 10 years for a survival rate of 58%. Other than the fatal hepatic toxicity, side effects from radiation were moderate and of short duration. One patient failed to complete therapy because of ascites, had two episodes of partial bowel obstruction (successfully treated conservatively), and subsequently survived more than 10 years. Two of three patients with stage C1 tumors, four of eight with C2 tumors, and one with a C3 tumor were long-term survivors. This study demonstrates the feasibility and acceptable toxicity of this adjuvant regimen. The numbers are too limited to evaluate survival, but all seven survivors have lived more than 10 years.

Inhibition by levamisole of the organic cation transporter rOCT1 in cultured rat hepatocytes

Levamisole is known to be subject to hepatic removal and metabolism and to biliary excretion. The aim of our work was to study the mechanism involved in the removal of this compound by the liver. For this purpose, we studied the influence of levamisole on the uptake and efflux of the model organic cation 1-methyl-4-phenylpyridinium (MPP(+)) by primary cultured rat hepatocytes. Levamisole (500 microm) was found to produce a strong inhibition (to 31+/-2% of control) of [(3)H]MPP(+)uptake. Moreover, efflux of [(3)H]MPP(+)was also potently reduced by levamisole (500 microm). Our results show that levamisole interferes with an hepatic organic cation transporter which accepts MPP(+)as a substrate. This mechanism most probably corresponds to rOCT1, and it might be responsible for the hepatic removal of levamisole from the blood circulation.

Total anorectal and partial vaginal reconstruction with dynamic graciloplasty and colonic vaginoplasty after extended abdominoperineal resection: report of a case

PURPOSE

Quality of life is altered after abdominoperineal resection, because of permanent iliac colostomy. Psychological rehabilitation is even more difficult after extended abdominoperineal resection to the vagina, because of the loss of both continence and sexual functions. We report the first case of total anorectal and vaginal reconstruction using dynamic graciloplasty and colonic vaginoplasty after extended abdominoperineal resection.

METHODS

A 46-year-old female underwent extended abdominoperineal resection with posterior colpectomy for a low rectal adenocarcinoma infiltrating the anal sphincter and vagina. Anorectal reconstruction was performed with coloperineal anastomosis and double dynamic graciloplasty. Vaginal reconstruction was performed using a 10-cm, isolated, rotated sigmoid loop. The procedure was performed in three stages, including abdominoperineal resection with reconstruction, implantation of the stimulator, and closure of the temporary ileostomy.

RESULTS

Resting and electrostimulated pressures of the neosphincter were 40 and 110 cm H2O respectively. Continence was achieved for formed stools two months after closure of the stoma, with spontaneous defecations (30-90 minutes). The patient experienced regular sexual activity six months after closure of the stoma.

CONCLUSION

This new original technique can be proposed in selected young females after extended abdominoperineal resection, to preserve continence, sexual activity, and body image.

Intraoperative lymphatic mapping and the sentinel node concept in colorectal carcinoma

BACKGROUND

Orderly progression of nodal metastases has been described for melanoma and breast cancer. The first draining lymph node, the sentinel node, is also the first to contain metastases and accurately predicts nodal status. The aim of this study was to assess the feasibility of lymphatic mapping and sentinel node biopsy in colorectal cancer.

METHODS

In 50 patients with colorectal cancer patent blue dye was injected around the tumour. After resection of the tumour the specimen was examined to identify blue-stained lymph nodes. Routine histopathological examination was performed on all nodes and the blue, haematoxylin and eosin-stained tumour-negative nodes were tested immunohistochemically.

RESULTS

Lymphatic mapping was possible in 35 of 50 patients (70 per cent). Pathological examination with haematoxylin and eosin staining showed lymph node metastases in 20 of 35 patients. In eight of these 20 patients the blue nodes showed tumour, while in 12 the blue nodes were not involved. This represents a false-negative rate of 60 per cent.

CONCLUSION

Lymphatic mapping using patent blue dye is feasible in colorectal cancer. The blue-stained nodes do not predict nodal status of the remaining lymph nodes in the resected specimen. The concept of lymphatic mapping and sentinel node identification is not valid for colorectal cancer.

Morbidities of adjuvant chemotherapy and radiotherapy for resectable rectal cancer: an overview

PURPOSE

Although adjuvant chemoradiotherapy may improve outcomes after surgery for high-risk rectal cancer, its toxicities are not well documented. This is a review of complications associated with adjuvant therapy in randomized, controlled trials.

METHODS

A MEDLINE and literature search was performed for randomized, controlled trials of adjuvant therapy for rectal cancer. Modalities of adjuvant therapy evaluated included preoperative radiotherapy, preoperative chemoradiotherapy, postoperative radiotherapy, and postoperative chemoradiotherapy. All documented complications were analyzed, including any effect on pelvic floor function and quality of life.

RESULTS

Short-term (acute) complications of preoperative radiotherapy include lethargy, nausea, diarrhea, and skin erythema or desquamation. These acute effects develop to some degree in most patients during treatment but are usually self-limiting. With preoperative radiotherapy the incidence of perineal wound infection increases from 10 to 20 percent. The acute toxicities after postoperative radiotherapy for rectal cancer occur in 4 to 48 percent of cases, and serious toxicities, requiring hospitalization or surgical intervention, occur in 3 to 10 percent of cases. Postoperative radiotherapy is associated with more complications than preoperative radiotherapy. The main problems with postoperative radiotherapy are small-bowel obstruction (5-10 percent), delay in starting radiotherapy caused by delayed wound healing (6 percent) and postoperative fatigue (14 percent), and toxicities precluding completion of adjuvant therapy (49-97 percent). The morbidity and mortality of both preoperative and postoperative radiotherapy are higher in elderly patients and when two-portal rather than three-portal or four-portal radiation technique is used. Meticulous radiation technique is important, and multiple fields of irradiation are mandatory. After combined adjuvant chemotherapy and radiotherapy acute hematologic and gastrointestinal toxic effects are frequent (5-50 percent). Delayed radiation toxicities include radiation enteritis (4 percent), small-bowel obstruction (5 percent), and rectal stricture (5 percent). Pelvic floor function and quality of life have not been well evaluated in randomized, controlled trials.

CONCLUSION

Adjuvant therapy for rectal cancer has considerable adverse effects. Adverse effects on bowel and sphincter function and quality of life have not been defined.

[Adjuvant and neoadjuvant therapy of rectal carcinoma. The current status]

BACKGROUND

The Consensus Conference of the German Cancer Society (CAO/AIO/ARO, 1.7.1998) has recently updated recommendations for patients with rectal cancer. Instead of a former reservation regarding the indication of adjuvant therapy for rectal cancer the actual version of the consensus particularly emphasizes the role of postoperative radiochemotherapy for stage-II/III tumors. This article reviews the most recent and ongoing trials of adjuvant and neoadjuvant therapy of rectal cancer.

RESULTS

To avoid local recurrence is the most important aspect in the primary treatment of rectal cancer. In some series, e.g. the results of the Surgical Department of the University of Erlangen, a significant correlation between local control and survival was noted. The final results of the Swedish Rectal Cancer Trial with 1168 randomized patients not only confirmed the potential of radiotherapy to reduce local recurrence rate, but also demonstrated a significant survival advantage for patients receiving short-course preoperative radiation therapy. Postoperative combination therapy is usual in the United States and in most European countries since the publication of two randomized trials of the Gastrointestinal Tumor Study Group (GITSG) and the North Central Cancer Treatment Group (NCCTG). The survival advantage resulting from an adjuvant radiotherapy with conventional doses and concurrent fluorouracil-based chemotherapy as compared to surgery alone was recently confirmed in a Norwegian trial. Protracted venous 5-fluorouracil infusion should further improve treatment results. Numerous phase-II studies have demonstrated the efficacy of preoperative radiochemotherapy with high rates of pathological response. Thus, neoadjuvant radiochemotherapy is recommended for patients with locally advanced tumor primarily not amenable to curative surgery. Prospective randomized trials are ongoing to clarify the role of preoperative versus postoperative combined treatment for patients with resectable rectal cancer.

CONCLUSION

Radiochemotherapy for rectal cancer is recommended as standard treatment outside clinical trials for stage II/III patients after curative treatment and for patients with T4-tumor prior to surgery. The optimal use of chemotherapy and the sequence of treatment modalities remains to be elucidated.

Treatment of colorectal cancer in patients aged over 75

Colorectal cancer is a common malignancy which is occurring with increasing incidence in the elderly. As the age of the population increases so the importance of this malignancy will gradually increase. In addition a high proportion of elderly patients present with intestinal obstruction secondary to colorectal cancer and therefore the management of intestinal obstruction in the elderly becomes an important surgical consideration. This review discusses the management of colorectal cancer in patients over the age of 75 in both the elective and emergency situations with particular reference to screening, surgical management and the use of adjuvant therapy.