Hiroaki Nakazato

Efficacy of immunochemotherapy as adjuvant treatment after curative resection of gastric cancer

In Japan the standard adjuvant treatment after resection of gastric cancer is intravenous mitomycin plus oral fluorouracil. We have assessed the efficacy of protein-bound polysaccharide (PSK) in addition to standard chemotherapy in patients who had undergone curative gastrectomy at 46 institutions in central Japan. 262 patients were randomly assigned standard treatment alone or with PSK. The minimum follow-up time was 5 years (range 5-7 years). PSK improved both the 5-year disease-free rate (70.7 vs 59.4% in standard treatment group, p = 0.047) and 5-year survival (73.0 vs 60.0%, p = 0.044). The two regimens had only slight toxic effects, consisting of nausea, leucopenia, and liver function impairment, and there were no significant differences between the groups. The treatments were clinically well tolerated and compliance was good. Addition of PSK to adjuvant chemotherapy with mitomycin and fluorouracil is beneficial as treatment after curative gastrectomy.

The usefulness of CEA and/or CA19-9 in monitoring for recurrence in gastric cancer patients: a prospective clinical study

AbstractBackground. Many studies on postoperative carcinoembryonic antigen (CEA) and/or carbohydrate antigen (CA)19-9 monitoring after operation for gastric cancer have been reported, but most have been retrospective. Methods. A nationwide observational study was implemented in 135 leading institutions in Japan to evaluate the significance of CEA and/or CA19-9 in postoperative monitoring for recurrence in patients with advanced gastric cancer. Three hundred and twenty-one patients examined in this analysis underwent radical gastrectomy at one of Japans leading institutions between November 1993 and March 1996 and had been followed up for at least 5 years. Serum levels of CEA and CA19-9 were examined preoperatively and every 3 months postoperatively, with diagnostic imagings, such as chest X-ray, computed tomography (CT), and ultrasonography also being performed every 3 months. Results. Recurrence was observed in 120 patients (peritoneum, 48; liver 16; lymph node, 16; multiple sites, 25; and others, 12). Sensitivities of CEA and either CEA or CA19-9, or both, for recurrence were 65.8% and 85.0%, respectively, both of which values were significantly higher than the preoperative positivities (28.3% and 45.0%, respectively). In most patients with high preoperative levels CEA and/or CA19-9, these tumor markers increased again at recurrence. Recurrent diseases were detected between 5 months after detection by diagnostic imagings and 12 months before detection by diagnostic imagings (mean of 3.1 ± 3.6 months before detection by diagnostic imagings) and between 10 months after detection by diagnostic imagings and 13 months before detection by diagnostic imagings (mean of 2.2 ± 3.9 months before detection by diagnostic imagings) by CEA and CA19-9 monitorings, respectively. Conclusion. These results suggest that CEA and/or CA19-9 monitoring after operation was useful to predict the recurrence of gastric cancer, especially in almost all the patients with high preoperative levels of these markers.

An individual patient data meta-analysis of adjuvant therapy with uracil–tegafur (UFT) in patients with curatively resected rectal cancer

Uracil–Tegafur (UFT), an oral fluorinated pyrimidine chemotherapeutic agent, has been used for adjuvant chemotherapy in curatively resected colorectal cancer patients. Past trials and meta-analyses indicate that it is somewhat effective in extending survival of patients with rectal cancer. The objective of this study was to perform a reappraisal of randomised clinical trials conducted in this field. We designed an individual patient-based meta-analysis of relevant clinical trials to examine the benefit of UFT for curatively resected rectal cancer in terms of overall survival (OS), disease-free survival (DFS), and local relapse-free survival (LRFS). We analysed individual patient data of five adjuvant therapy randomised clinical trials for rectal cancer, which met the predetermined inclusion criteria. These five trials had a combined total of 2091 patients, UFT as adjuvant chemotherapy compared to surgery-alone, 5-year follow-up, intention-to-treat-based analytic strategy, and similar endpoints (OS and DFS). In a pooled analysis, UFT had significant advantage over surgery-alone in terms of both OS (hazard ratio, 0.82; 95% confidence interval (CI), 0.70–0.97; P=0.02) and DFS (hazard ratio, 0.73; 95%CI, 0.63–0.84; P<0.0001). This individual patient-based meta-analysis demonstrated that oral UFT significantly improves both OS and DFS in patients with curatively resected rectal cancer.

Efficacy of adjuvant immunochemotherapy with OK-432 for patients with curatively resected gastric cancer: a meta-analysis of centrally randomized controlled clinical trials.

The benefit of immunochemotherapy employing a streptococcal preparation, OK-432 (Picibanil), in patients with curatively resected gastric cancer was reassessed by meta-analysis of data from 1,522 patients enrolled in six clinical trials with central randomization. All six trials began between 1985 and 1993, and patients were followed-up for at least 3 years after surgery and enrollment of the last patient. In these trials, standard chemotherapy was compared with the same chemotherapy plus OK-432. The endpoint was overall survival and intent-to-treat analysis was done without patient exclusion. Data were analyzed using the Mantel-Haenszel method. The 3-year survival rate for all eligible patients in the six trials was 67.5% in the immunochemotherapy group versus 62.6% in the chemotherapy group. The 3-year overall survival odds ratio was 0.81 (95% confidence interval: 0.65–0.99). The treatment effect was shown to be statistically significant (p = 0.044). The results of this meta-analysis suggest that immunochemotherapy after surgery with OK-432 can improve the survival of patients with curatively resected gastric cancer.

Meta-analysis of Adjuvant Immunochemotherapy Using OK-432 in Patients With Resected Non-Small-Cell Lung Cancer.

The benefits of immunochemotherapy with a penicillin-treated, lyophilized preparation of Streptococcus pyogenes, OK-432 (Picibanil), were reassessed in patients with resected non–small-cell lung cancer through a meta-analysis based on data from 1,520 patients enrolled in 11 randomized clinical trials. All 11 trials were started before 1991, and the subjects had been followed up for at least 5 years after surgery and randomization. In these trials, standard chemotherapy was compared with the same therapy plus OK-432. The endpoint of interest was overall survival, and analysis was based on intent-to-treat population without patient exclusion. Data were analyzed using the Mantel-Haenszel method. The 5-year survival rate for all eligible patients in the 11 trials was 51.2% in the immunochemotherapy group versus 43.7% in the chemotherapy group. The odds ratio (OR) for overall survival was 0.70 (95% CI = 0.56–0.87, p = 0.0010). Analysis of four trials in which central randomization was performed also reconfirmed a significantly longer survival time for the immunochemotherapy group (OR = 0.66, 95% CI = 0.44–1.00, p = 0.049). Based on these results of meta-analysis, it is postulated that postoperative adjuvant immunochemotherapy using OK-432 might improve the survival of patients after resection of non–small-cell lung cancer.

Preoperative serum immunosuppressive acidic protein (IAP) test for the prognosis of gastric cancer: a statistical study of the threshold level and evaluation of the effect of the biological response modifier PSK.

The prognostic value of immunosuppressive acidic protein (IAP), which is known to suppress various immune responses in cancer patients, was studied in a prospective randomized trial of advanced gastric cancer patients, designed to evaluate the effect of PSK, a kind of biological response modifier with protein-bound polysaccharides. Preoperative serum IAP levels were determined in 228 patients who received radical gastric resection and tests conducted in one laboratory by the single radial immunodiffusion (SRID) method. All patients were followed up for 24 months or more. There was an overall significant difference in disease-free survival time in favour of the PSK-treated group compared with the control group. Preoperative IAP values were strongly associated with disease-free survival time. The statistical analysis to define an appropriate cut-off level for IAP was performed using Coxs proportional hazards model. The most significant difference was observed at the threshold value of 580 μg/ml, the hazard ratio being 2.13 with a 95% confidence interval [1.17, 3.88] (P=0.013). Patients in the PSK-treated group with a preoperative IAP of lower than 580 μg/ml showed improved disease-free survival (P=0.029), however, no significant difference was seen between the two groups when the preoperative IAP exceeded the threshold level. From these results, 580 μg/ml is postulated to be the most appropriate threshold value for predicting the prognosis of advanced gastric cancer patients, and it is suggested that PSK would be most effective in patients whose preoperative IAP level is lower than the threshold level.

Meta-Analysis of Five Studies on Tegafur plus Uracil (UFT) as Post-Operative Adjuvant Chemotherapy for Breast Cancer

Meta-analysis of 5 studies on postoperative breast cancer cases (2 studies on surgery alone vs. tegafur plus uracil (UFT) and 3 studies on tamoxifen (TAM) alone vs. TAM + UFT) were carried out to evaluate the anticancer drug UFT in oral postoperative adjuvant chemotherapy. Of the 1973 patients enrolled, 1898 were eligible and 75 were excluded (exclusion rate 3.8%). There was no bias in major background factors in either the UFT-treated (965) or non-UFT-treated (933) groups. The reduction in the odds of death and the odds of recurrence were 17 ± 17% (p = 0.33) and 21 ± 11% (p = 0.060), respectively. Multivariate analysis using Cox’s proportional hazards model emphasized the effectiveness of UFT treatment for suppression of recurrence compared with non-treatment with UFT (p = 0.038). Suppression of recurrence was remarkable in the group treated with UFT for 2 years. (the reduction in the odds of recurrence: 23 ± 11%, p = 0.048) Stratified analysis was applied concerning recurrence, and improved results were obtained in premenopausal cases (the reduction in the odds of recurrence: 33 ± 11%, p = 0.019). These results suggested that UFT treatment for 2 years was effective as postoperative adjuvant chemotherapy for stage I – IIIA breast cancer for the prolongation of the reccurence-free survival period.

Impact of splenectomy and immunochemotherapy on survival following gastrectomy for carcinoma: Covariate interaction with immunosuppressive acidic protein, a serum marker for the host immune system

The role of the spleen in tumor immunology is still controversial in that it can either enhance or suppress the antitumor immune response depending on the tumor-bearing host. To clarify this biphasic effect of the spleen, a clinical evaluation of splenectomy in conjunction with immunotherapy and the host immune status was performed in gastric cancer patients. The effect of splenectomy and immunotherapy in 253 gastric cancer patients enrolled in a prospective randomized trial (SIP) was analyzed using the Cox’s proportional hazards model in terms of the covariate interaction of the preoperative immunosuppressive acidic protein (IAP) level. In patients with high IAP levels (>580 μg/ml) with predicted negative antitumor immune reactions splenectomy improved the prognosis. In patients with lower IAP values, conversely, the preservation of the spleen and immunotherapy demonstrated a significant benefit to survival. The spleen was shown to have a biphasic activity in terms of its antitumor immune response depending on the IAP level of the patient. The effect of immunotherapy is significantly influenced by the activity of spleen cells. The preoperative IAP level is therefore considered to be a possible indicator for the effectiveness of splenectomy and immunotherapy in curatively resected gastric cancer patients.

Association between preoperative plasma CEA levels and the prognosis of gastric cancer following curative resection

A large-scale retrospective study was undertaken to evaluate the association between preoperative plasma carcinoembryonic antigen (CEA) levels and the prognosis of 2768 gastric cancer patients who underwent curative gastrectomy between 1983 and 1984 at 66 leading medical institutions in Japan Postoperative follow-up was at least 5 years. Preoperative plasma CEA levels were also analysed against other prognostic factors. Preoperative plasma CEA levels showed strong correlations to the degree of lymph node metastasis (P < 0.001), TNM stage (P = 0.004) and the histopathology of the gastric cancer (P < 0.001). Preoperative CEA levels were also evaluated against survival, after being adjusted for the effect of clinically important factors by multivariate analysis. Patients with lower preoperative plasma CEA levels survived significantly longer than patients with higher CEA levels (P = 0.0001). This analysis demonstrates that curatively resected gastric cancer patients with higher preoperative plasma CEA levels have a poorer prognosis than those with lower levels, despite the adjustment for the effects of major prognostic factors.

In vivo and in vitro activation of macrophages with a cyanine photosensitizing dye, platonin

A cyanine photosensitizing dye, platonin, is a potent macrophage-activating agent. Four days after the administration to mice of small amounts of platonin (20–40 ng/mouse), peritoneal macrophages exhibited greatly enhanced Fc-receptor-mediated phagocytic and superoxide-generating capacities. Much higher doses (more than 3000 ng/mouse) did not have this effect. Photodynamic experiments for macrophage activation were performed by exposing mouse peritoneal cells (mixture of macrophages and B and T lymphocytes) to white fluorenscent light (3 J m−2s−1) in media containing various low concentrations of platonin. A short exposure to white fluorescent light (5 s, 15 J m−2) of peritoneal cells in a medium containing 3 ng platonin/ml produced a maximal level of phagocytic capacity of macrophages. Although platonin absorbs light poorly at wavelengths longer than 630 nm, the region of the spectrum in which the tissues are transparent allows reasonable penetration of light. Thus, we designed experiments in which peritoneal cells were exposed to a red fluorescent light (0.5 J m−2s−1). In a medium containing 10 ng platonin/ml with 15 J m−2 red light, a markedly enhanced ingestion activity of macrophages was observed. Photodynamic treatment of peritoneal macrophages alone did not activate macrophages. Thus, participation of nonadherent cells is required for photodynamic activation of macrophages, implying that a macrophage-activating factor is generated within the nonadherent cells and transmitted to macrophages.