Gastric cancer: a neoplastic enigma

Early gastric cancer in the young: clinicopathological study

BACKGROUND

Thirty-four cases of early gastric carcinoma in patients under 50 years of age treated in the period from 1985 to 1995 were reviewed.

METHODS

These constituted 3.7% of 923 cases of gastric cancer in patients of all ages that were treated at Sendai National Hospital during the same 10-year period. Data were compared with those of 194 patients 50 years of age or older.

RESULTS

The incidence of gastric cancer in men and women was almost the same in both groups. Tumours tended to be located distally in the stomach. Macroscopically, depressed lesions were more common in younger patients. Significant differences were observed in depth of invasion, histological type and histological growth patterns.

CONCLUSIONS

The distinctive histological features of early gastric cancer in younger patients were a diffuse type of cancer with infiltrative tumours in the mucosal layer. The prognosis of younger patients was similar to that of older patients.

CPT-11 in gastrointestinal cancer

Colorectal, gastric and pancreatic cancers are major health problems worldwide. Although surgery is a curative option in 50% of patients with colorectal cancer, it is much less effective in gastric cancer (< 20% of patients) and virtually ineffective in pancreatic cancer. These three cancer types also respond poorly to chemotherapy. CPT-11 (irinotecan), a novel cytotoxic drug, is now available in many countries as a single agent for second-line therapy in metastatic colorectal cancer. The response rate in the pivotal European study of metastatic colorectal cancer patients was 14%, with a median duration of response of 8.5 months. There was also a high rate of disease stabilisation (44%), with a median duration of 4.8 months. Median survival time was 10.4 months. The dose-limiting toxicities (DLT) for CPT-11 are delayed diarrhoea and neutropenia, both of which are schedule dependent and non-cumulative. These encouraging data in second-line therapy support the further study of CPT-11 as first-line therapy for colorectal cancer in combination with other agents. Four Japanese trials of CPT-11 as first- and/or second-line single-agent therapy for advanced gastric cancer report response rates of 18-43%. The median durations for response and survival time in the late phase II trial were 2.3 months and 5.8 months, respectively. These results are in the range of those reported for sequential high-dose methotrexate and 5-fluorouracil (5-FU)/doxorubicin (FAMTX), etoposide/leucovorin/5-FU (ELF) or cisplatin/5-FU therapy in gastric cancer. Data are currently available from five phase II studies of CPT-11 in advanced pancreatic cancer: four Japanese and one European. The response rates ranged from 9 to 19%. The median duration of survival for all treated patients in the European study was 5.2 months. CPT-11 in combination with 5-FU is currently being investigated in Japan, the U.S.A. and Europe in patients with gastrointestinal tumours. CPT-11 is also being evaluated in combination with each of the following agents: oxaliplatin, docetaxel, raltitrexed, etoposide and mitomycin C. Japanese studies of CPT-11 plus cisplatin in patients with gastric cancer have produced response rates of 48-59%. These encouraging data highlight the potential for CPT-11 in combination therapy for gastrointestinal tumours.

Detection of P-glycoprotein in frozen and paraffin-embedded gastric adenocarcinoma tissues using a panel of monoclonal antibodies

AIMS

Most chemotherapeutic regimens used against gastric carcinoma include anthracyclines whose effectiveness can be impaired by the presence of P-glycoprotein. In order to obtain a reliable pattern of P-glycoprotein expression in these tumours an immunohistochemical study using a panel of anti-P-glycoprotein antibodies was performed in frozen and paraffinized tissues.

METHODS AND RESULTS

Frozen and paraffinized samples from 25 gastric carcinomas were immunohistochemically analysed using a panel of four anti-P-glycoprotein monoclonal antibodies including C219, MRK16, JSB-1 and C494. Semiquantitative analysis indicated that moderate or high P-glycoprotein levels were detected in 40% to 76% of gastric adenocarcinomas, depending on the anti-P-glycoprotein antibody used. The antibody C494 was the most sensitive in detecting P-glycoprotein in both frozen and paraffinized gastric carcinoma samples. Moreover, C494 showed a pattern of staining exclusively associated with the plasma membrane, in contrast to the cytoplasmic with reinforcement of plasma membrane pattern displayed by the other three antibodies. Significant differences in P-glycoprotein levels were obtained when C494 and MRK16 were used in frozen tissues. Finally, detection of P-glycoprotein in frozen samples did not improve when compared to paraffinized ones.

CONCLUSIONS

It appears that P-glycoprotein is frequently expressed in gastric adenocarcinomas, and the use of C494 complemented by JSB-1 is recommended for reliable detection of P-glycoprotein in this neoplasm.

Follow-up of patients resected for gastric cancer

In this study we used a cost-outcome analysis to evaluate our follow-up protocol for patients who had been resected for gastric cancer. We designed a descriptive cross-sectional trial through consecutive sampling of patients who had undergone resection of gastric carcinoma and were followed in our outpatient department during 1991. Serological (CEA) and or imaging procedures were pathologic at least two months prior to the onset of symptoms in 33% of recurrences. No significant correlation was found between serum CEA levels and CEA tumor tissue staining in patients who recurred. Only 17% of patients who relapsed underwent further treatment (surgery and chemotherapy) with no improvement found in terms of survival. The overall cost per year has been estimated at US$ 6118. Our results show that serological levels of CEA and available imaging techniques for routine follow-up provide little advantage in diagnosing gastric cancer recurrence over clinical surveillance alone.

Local recurrence and long-term survival in patients with gastric cancer--analysis of possible impact of clinicopathological parameters

In a retrospective study comprising 88 patients operated upon with curative intent a number of histopathological parameters of possible prognostic value regarding local recurrence and long-time survival were analysed. Local recurrence within 5 years was found in 28 patients (32%) of which 17 (61%) were diagnosed within the first 2 years. Crude survival rates at 5 and 10 years were 25% and 15%. According to Laurén's classification the results indicated better, but not significant, 5- and 10-year survival for the diffuse type (36% vs 25%). The probability of 10-year survival suggested a better (P = 0.06) prognosis for tumours in the middle third of the stomach, and for patients operated with total gastrectomy (P = 0.025). The probability of recurrence in relation to lymph node involvement suggested a more favourable prognosis (P = 0.06) for patients without lymph node metastases, and in relation to tumour fibrosis a less favourable prognosis for pronounced fibrosis (P = 0.001).

Resection margin in patients with gastric cancer associated with esophageal invasion: clinicopathological study

We investigated the correlations between resection margin involvement by carcinoma and a number of clinicopathological features in patients with gastric cancer and esophageal invasion. From January 1968 to December 1988, 1,040 patients with carcinoma of the stomach underwent gastric resection. Thirty-nine patients had tumor infiltration of the esophagus on histological examination of the resected specimens. The patients were divided into two groups on microscopic examination: those in whom the resection margin was less than 5 mm wide, and those in whom it exceeded 5 mm microscopically. There were 6 and 33 patients in the narrow and wide margin groups, respectively. There were statistically significant differences in tumor size, depth of cancer invasion, and macroscopic appearance between the two groups. The risk of resection margin involvement was high in tumors with the following features: large Borrmann type 4 tumor (macroscopic appearance and size) and infiltrative carcinoma (depth of invasion).