Adjuvant therapy for resectable rectal and colonic cancer

Tumor cell PD-L1 predicts poor local control for rectal cancer patients following neoadjuvant radiotherapy

The tumor cell (TC) PD-L1 expression has been reported by several studies in various types of cancer, and it reduces the cytotoxicity of T-cells toward cancer and evades the anticancer immune response. Herein, our study focuses on the impact of PD-L1 expression in prognosis and the correlation with clinical prognostic factors for local advanced rectal cancer with neoadjuvant radiotherapy (RT). A total of 68 rectal cancer patients treated with neoadjuvant RT were retrospectively enrolled in the present study. PD-L1 expression was investigated using immunohistochemistry. A regression model was used to identify prognostic factors associated with the disease-free survival, the local recurrence-free survival (LRFS), and the overall survival rates. The median follow-up was 32.5 months. Seven patients presented TC PD-L1 positive (TC PD-L1+), while the others were TC PD-L1 negative (TC PD-L1−). TC PD-L1+ patients showed frequent tumor recurrence than TC PD-L1− patients. Several patients with TC PD-L1− underwent long-course RT. TC PD-L1 expression was similar to interstitial cell (IC) PD-L1 expression, and the relationship between IC PD-L1 and pathological T stage was observed. TC PD-L1+ was related to poor LRFS. The multivariate analysis showed TC PD-L1+ as an independent negative prognostic factor for LRFS. In conclusion, TC PD-L1 expression putatively predicts the LRFS for patients with rectal cancer following neoadjuvant RT. The patients with TC PD-L1+ are susceptible to high local recurrent rate, thereby proposing a novel immunotherapeutic strategy for PD-L1 inhibition-mediated control.

Albumin-drug conjugates in the treatment of hepatic disorders

INTRODUCTION

This review deals with the use of serum albumin (SA) as a carrier for the selective delivery of drugs to liver cells.

AREAS COVERED

The synthesis and properties of the SA conjugates prepared to enhance the performance of the drugs used in the treatment of viral hepatitis, hepatocellular carcinoma (HCC), liver micrometastases and hepatic fibrosis are reported.

EXPERT OPINION

Studies in humans and laboratory animals demonstrated the capacity of SA conjugates to accomplish a liver targeting of the drugs, but at the same time underscored their limits and drawbacks, which can explain why to date these complexes did not reach a practical application. The major drawback is the need of administration by intravenous route, which prevents long-term daily treatments as required by some liver pathologies, such as chronic virus hepatitis and fibrosis. At present, only a conjugate carrying doxorubicin and addressed to the treatment of HCC showed in laboratory animals a solid potentiality to improve the value of the coupled drug. In the future, conjugation to SA could remain a successful strategy to permit the administration of drugs with rapid resolutive effects inside liver cells without causing severe extrahepatic adverse reactions.

Postoperative low pelvic radiotherapy and chemotherapy for stage II and III rectal cancer

OBJECTIVES

To evaluate whether postoperative low pelvic radiotherapy (RT) combined with chemotherapy is an appropriate treatment for stage II and III rectal cancer.

METHODS

Between November 1997 and May 2006, 104 patients with stage II and III rectal cancer underwent surgery as the primary treatment followed by postoperative RT combined with chemotherapy in our institute and were reviewed retrospectively. Sixty-nine patients received low pelvic RT only (upper margin at 1 cm above the low end of the sacroiliac joint; median dose 54 Gy) (low pelvic RT group) and the other 35 patients received whole pelvic RT (upper margin at the mid L5; median dose 43.2 Gy) and subsequently received a boost to the low pelvis (total median dose 54 Gy) (whole pelvic RT group).

RESULTS

The 5-year overall survival rate, local control rate, and distant metastasis-free rate were 72% versus 63%, 86% versus 84%, and 66% versus 62% for low pelvic versus whole pelvic RT group. There were no statistical differences in these 2 groups. Two patients (2.9%) of the low pelvic RT group and 2 patients (5.7%) of the whole pelvic RT group developed upper pelvis relapse, which was out of the low pelvic field. The incidence of Grade 3 to 5 small bowel late complications of the low pelvic RT group was significantly less than that of the whole pelvic RT group (4.3% vs. 20%) (P=0.029).

CONCLUSIONS

Low pelvic RT significantly reduces small bowel late complications and does not compromise the overall survival rate, local control rate, and distant metastasis-free rate.

Improving patient survival with the colorectal cancer multi-disciplinary team

OBJECTIVE

There is little information on the impact of the colorectal multi-disciplinary team (MDT) in the United Kingdom. Our single operator presented his patients before and after the inception of an MDT meeting in June 2002. The aim of this study was to assess the effect of this on his patients' survival, and trends in the use of adjuvant chemotherapy.

METHOD

Data were collected on all patients (n = 310) undergoing colectomy for colorectal cancer by one surgeon. Excluding patients with Dukes A stage, the pre-MDT cohort from January 1997 to May 2002 was 176 and the post-MDT cohort from June 2002 to December 2005 was 134. Three-year survival rates were calculated using Kaplan-Meier life table analysis. Prognostic factors were analysed using Cox-proportional hazard regression, and chemotherapy data analysed using the chi-squared test. Independent prognostic indicators of chemotherapy prescription were examined using binary logistic testing.

RESULTS

MDT status was shown to be an independent predictor of survival on hazard regression analysis (P = 0.044). A significantly greater number of patients were prescribed adjuvant chemotherapy in the post-MDT cohort (P = 0.0002). MDT status was shown to be a significant prognostic indicator of chemotherapy prescription (P < 0.0001). Three-year survival for Dukes C patients was 58% in the pre-MDT group, and 66% in the post-MDT group (P = 0.023).

CONCLUSION

There was a significant increase in patients undergoing adjuvant postoperative chemotherapy after the inception of the MDT. This was associated with a significant survival benefit in patients with Dukes C disease. The data suggest that the MDT process has resulted in an increase in the prescription of adjuvant chemotherapy, with 3-year survival being greater after its inception.

Surgery-predominant combined treatment for colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and the fifth leading cause of cancer-related mortality in China with an increasing trend, which is emphasizing the need for improvements in therapeutic options. The 5-year survival rate of surgery, the first-line treatment for CRC, is just about 50 percent. In recent years many patients with CRC have benefited from the combined treatment with surgery for CRC, which integrates chemotherapy, radiotherapy, concurrent chemoradiotherapy, biotherapy, traditional Chinese medicine, etc., especially patients at advanced stage. This paper highlighted current situation for combined treatment with surgery for CRC.

Surgery for local recurrence of rectal cancer

OBJECTIVE

Despite improvement in management of primary rectal cancer, 2.6-32% of patients develop local recurrence. A proportion of these patients can be amenable to salvage surgery. The present article reviews the evidence for and against the surgical management for local recurrence of rectal cancer, the role of adjuvant and intraoperative radiotherapy (IORT), and evaluates short and long-term outcomes.

METHOD

A literature search was performed using Medline, Embase, Ovid and Cochrane database for studies between 1980 and 2005 assessing surgical management of local recurrence of rectal cancer and the evidence was critically evaluated.

RESULTS

Nearly 50% of rectal cancer recurrences are local and are therefore potentially amenable to curative resection. Preoperative imaging is important for appropriate selection of patients for surgery and preoperative adjuvant therapy is essential. Five-year survival following resection ranges from 18% to 58% with 5-year survival following complete resection of over 35% though morbidity ranges from 21% to 82%. Neoadjuvant radiotherapy is beneficial and IORT may have a contributory role in treatment. Aggressive surgical treatment favourably affects quality of life and is cost effective. Surgery for local recurrence can result in significant long-term survival with acceptable morbidity and improved quality of life in appropriately selected patients. Assessment in a specialist centre familiar with these techniques is essential.

Floxuridine coupling with lactosaminated human albumin to increase drug efficacy on liver micrometastases

BACKGROUND

Conjugates of nucleoside analogues with galactosyl terminating peptides selectively enter hepatocytes through the asialoglycoprotein receptor. After intracellular release from the carrier, the drugs partly exit from hepatic cells into hepatic blood.

AIMS

To establish whether administration of a conjugate of floxuridine with lactosaminated human albumin selectively enhances drug concentrations in hepatic blood. Floxuridine is a fluoropyrimidine active on human colorectal cancer, a tumour which metastasises first to the liver.

METHODS

In rats injected with free or conjugated floxuridine, plasma levels of the drug were determined in hepatic veins and in inferior vena cava, in order to measure drug concentrations in hepatic blood and in the systemic circulation, respectively.

RESULTS

Ratios between floxuridine levels in hepatic veins and those in systemic circulation were found to be seven times higher in rats injected with the conjugate (p=0.000).

CONCLUSIONS

The present results suggest that coupling to lactosaminated albumin might improve the effect of floxuridine in adjuvant chemotherapy of colorectal cancer by exposing the cells of liver micrometastases (nourished by hepatic sinusoids) to enhanced drug concentrations.

Conjugates of nucleoside analogs with lactosaminated human albumin to selectively increase the drug levels in liver blood: requirements for a regional chemotherapy

Nucleoside analogs (NAs) conjugated with galactosyl terminating peptides selectively enter hepatocytes via the asialoglycoprotein receptor and, after intracellular release from the carrier, partly exit from these cells into the bloodstream, resulting in higher concentrations in liver blood than in systemic circulation. Therefore, conjugates of anticancer NAs can be exploited to accomplish a loco-regional noninvasive treatment of liver micrometastases. In the present experiments we studied whether the enhancement of drug levels in liver blood achieved when NAs are given in the coupled form depends on the rate of drug elimination from the bloodstream. Three NAs, adenine arabinoside (ara-A), 5-fluoro-2'-deoxyuridine (FUdR), and 2',2'-difluorodeoxycytidine, were coupled with lactosaminated human albumin, a galactosyl terminating carrier. In rats that received an intravenous bolus injection of these conjugates, we compared the drug concentrations in liver blood to those in the systemic circulation. We found that enhanced levels of NAs in liver blood were only achieved by administering the conjugates of the drugs (ara-A and FUdR), which are rapidly cleared from the bloodstream. Increased drug levels also were obtained when ara-A and FUdR conjugates were slowly infused (a way of administration often used for anticancer drugs). The experiments also showed that galactosyl terminating conjugates of NAs might have the potential to produce a therapeutic effect only when the coupled drugs are active at low blood concentrations, since the amounts of drugs introduced into hepatocytes and released by these cells in the bloodstream cannot be increased when the receptor for the hepatic uptake of galactosyl terminating peptides is saturated.

The development of novel mouse monoclonal antibodies against the CC531 rat colon adenocarcinoma

In this paper we describe 4 new monoclonal antibodies to be applied in rat models for cancer. The monoclonal antibodies were obtained by immunizing Balb/c mice with CC531 rat colon adenocarcinoma cells. Hybridomas were produced and 4 were selected for their reactivity with CC531 in vitro (MG1, 2, 3 and 4). All 4 antibodies recognized other rat tumour cell lines and showed limited cross-reactivity with normal rat tissues. Intraperitoneally injected MG1, 2 and 4 homed to in vivo growing, artificially induced CC531 liver metastases. In these in vivo experiments, limited cross-reactivity with normal rat tissues, predominantly of the gastro-intestinal tract, was found. MG4 was found to enhance lysis of CC531 tumour cells mediated by IL-2 activated, cultured natural killer cells. These antibodies are potentially useful for antibody-based laboratory techniques and for investigation of antibody-based immunotherapy of cancer in a rat model.

Rectal cancer: changing patterns of referral for radiation therapy 1982-1997

BACKGROUND

The purpose of the present study was to evaluate the changing role of radiation therapy in rectal cancer and to determine the patterns of referral of patients during a 15-year period.

METHODS

From 1982 to 1997, 464 patients with carcinoma of the rectum were referred to the Department of Radiation Oncology, Royal Prince Alfred Hospital: 79% of patients had locoregional disease alone and 21% had distant metastasis. Radiation therapy consisted of irradiation (definitive or palliative) alone to the primary tumour in 9.7% of cases; preoperative radiation in 7.3% of cases: preoperative chemoradiation in 7.5% of patients: postoperative radiation in 15.3% of patients: postoperative chemoradiation in 12.31% of patients: treatment of pelvic recurrence in 23.5% of patients and treatment of metastases in 9.1% of patients. The remainder were treated elsewhere (1.9%) or not treated (13.4%).

RESULTS

There was an average annual 14% increase in referrals over the accrual period. Recurrent rectal cancer decreased from approximately 30% of referrals during 1982-91 to approximately 10% in 1995-7. The use of postoperative adjuvant radiation reached a peak of 50% in 1993. The use of preoperative radiation increased suddenly in 1994 from < 10% to a sustained rate of approximately 30% of referrals. The use of chemoradiation commenced in 1990 for postoperative adjuvant treatment and in 1994 for preoperative treatment. The median survival time from initial diagnosis was 35 months, with 2- and 5-year survival rates of 62 and 28%, respectively. Survivals at 5 years for patients treated with preoperative and postoperative radiation (with or without chemotherapy) and with recurrent disease were 56, 44 and 21%, respectively.

CONCLUSIONS

The present study illustrates the changing role of radiation therapy in the management of rectal cancer. The increase in referrals over the observation period was due to increased multidisciplinary input into the initial management of these patients, based on reported clinical trials. The steady increase in the use of adjuvant therapy has paralleled a decrease in referrals for treatment of recurrence and reflects current clinical results. The sequencing of adjuvant therapy is changing currently, with greater emphasis on preoperative adjuvant treatment. Currently most adjuvant therapy includes chemotherapy.

Capecitabine, a new oral fluoropyrimidine for the treatment of colorectal cancer

Capecitabine (Xeloda)(R) was developed as a tumour-selective fluoropyrimidine carbamate to achieve higher intratumoural 5-FU level and lower toxicity than 5-FU. Capecitabine passes unchanged through the gastrointestinal tract and is metabolised in the liver to 5'-deoxy-5-fluorocytidine (5'-DFCR). Here it is converted to doxifluridine (5'-DFUR) and finally, 5'-DFUR is metabolised by thymidine phosphorilase to 5-FU at the tumour site. Preclinical studies have demonstrated capecitabine's activity in both 5-FU-sensitive and 5-FU-resistant tumours. In a randomised phase II trial in advanced colorectal cancer the recommended dose and schedule of Capecitabine is 2.510 mg/m(2)/day (total dose divided into two equal morning and evening doses) given in an intermittent schedule (2 weeks on/1 week off). Phase III trials in patients with advanced colorectal cancer show a better response rate than the Mayo Clinic schedule, with no differences in terms of DR, PFS. Diarrhoea and hand-foot syndrome were the principal grade 3/4 toxicities noted, occurring in 10% and 16% of patients, respectively. The selectivity of this drug opens an important prospective in the treatment of colorectal cancer in advanced and adjuvant setting.

Rectal cancer recurrence: factors and mechanisms

OBJECTIVE

There have been significant developments in treatment for rectal carcinoma, both in surgical and adjuvant therapy. They may however have associated morbidity and hence individualized therapy for rectal cancer is desirable, to optimize treatment but avoid over-treatment for cases where the risk of recurrence is low.

MATERIALS AND METHODS

A literature review was undertaken of the reported incidence of recurrence of rectal carcinoma following curative surgery, factors which predispose to recurrence and proposed mechanisms for recurrence, and the evidence for each critically evaluated.

RESULTS

The incidence of local recurrence of rectal carcinoma following curative resection ranges from 2.6% to 32%, with an average of 15%. Tumour stage is the strongest predictor of tumour recurrence. Upstaging using molecular biology may predict increased risk of recurrence but is not yet proven. Histological factors including differentiation and vascular invasion increase recurrence but are imprecise. Tumour microvascular density and vascular endothelial growth factor (VEGF) levels may be predictive but need refinement. Adequate resection margins are important but recurrence may occur despite this. Tumour cell spillage and distant dissemination may be a mechanism for tumour recurrence following curative resection, but further research is required before this could be applied clinically.

CONCLUSION

Recurrence of rectal cancer remains a significant problem following 'curative' surgery. Multiple factors may influence recurrence risk, though currently however only tumour stage and histological resection margins have demonstrated sufficient importance for management decisions to be made upon them.

Results of a selective policy for preoperative radiotherapy in rectal cancer surgery

OBJECTIVE

Preoperative radiotherapy (pRT) for rectal cancer may reduce local recurrence and improve survival. This study was undertaken to assess a selective policy of pRT in rectal cancer. The aim was to determine whether patients likely to have involved circumferential margins (CRM) could be reliably selected for pRT using clinical criteria. We have used CRM and delay in surgery as outcome measures.

PATIENTS AND METHODS

Seventy-nine patients with rectal cancer were assessed for preoperative radiotherapy using clinical criteria.

RESULTS

Twelve of 26 (46%) pRT patients had positive CRM compared with three of 53 (5.6%) who did not receive pRT (P < 0.0001). Using pRT resulted in patients waiting a further 21 days before surgery (pRT 34 days vs no pRT 13 days; P < 0.0001).

CONCLUSION

This policy has been effective in selecting patients most likely to benefit from radiotherapy and has avoided excessive delays prior to surgery. However, almost half of the pRT patients did not have involved CRM. With improved imaging techniques we may be able to refine our selection criteria further.

Prospective evaluation of formalin therapy for radiation proctitis

BACKGROUND

Radiation proctitis is a troublesome complication of radiation therapy for as many as 75% of patients after pelvic irradiation. Five percent progress to chronic radiation proctitis complicated by telangiectasias and hemorrhage. The utility of formalin rectal instillation for treatment of bleeding is prospectively evaluated in this study.

METHODS

Eleven patients (9 male, 2 female) with rectal bleeding after pelvic irradiation were treated with formalin therapy. In a single treatment, 4% formalin was instilled into the rectum in four separate 20-cc aliquots with total mucosal contact time of approximately 15 minutes. Patients were initially evaluated at 7 to 10 days and 1 month postoperatively and assessed for bleeding.

RESULTS

All patients presented with rectal bleeding. Twenty-seven percent required transfusion. Thirty-six percent had failed other previous therapy. In follow-up of 3 to 64 months, 100% had initial success with cessation of bleeding. Three patients had recurrent bleeding; none required transfusion. One patient required repeat formalin instillation, with no further bleeding at 3 months follow-up.

CONCLUSION

Local rectal instillation of 4% formalin is an efficacious therapy for treatment of radiation-induced lower gastrointestinal bleeding.

Chemotherapy in the elderly

Much of the increase in cancer incidence is explained by the increasing number of elderly in the population. Even at a relatively advanced age, many have a life expectancy in the range of, or longer than, the expected 5- or 10-year survival of the malignant disease diagnosed. There are some specific problems related to treatment with chemotherapy in this age group. There is a decline in organ function, especially renal and cardiac, as well as other limitations in relation to vision, hearing and mobility. This means that we have to adopt a different attitude both to indications for chemotherapy and to what agents to use. Social and socioeconomic factors also have to be taken into consideration.