Yoichi Kikuchi

Prognostic factors associated with differentiated thyroid cancer

A multivariate analysis was conducted on the survival data of 180 patients who underwent curative resection for differentiated thyroid cancer between 1966 and 1987, and the 10- and 20-year survival rates were found to be 80.6% and 73.1%, respectively. A survival analysis was also performed, testing the following factors: the patients age at the time of diagnosis, tumor size, extraglandular extension, nodal status, distant metastases, operative procedure, sex, and histology. A univariate analysis found the initial six factors to be significant prognostic variables, but the latter two to be of no significance. On the other hand, the multivariate analysis showed that distant metastases, age, and tumor size were the most significant prognosticators. Thus, the age of the patient should be taken into consideration during the follow-up of treatment for differentiated thyroid cancer.

LYMPH NODE METASTASIS AND RECURRENCE IN GASTRIC CANCER INVADING THE SUBMUCOSAL LAYER

In order to know the possibility of reduction surgery for gastric cancer invading the submucosal layer (sm gastric cancer), recurrence and lymph node metastasis were examined histopathologically, by dividing subjects into 3 groups according to the extent of infiltration. The subjects were 90 patients who were diagnosed as having a sm gastric cancer pathologically and whose prognoses were known. When they were classified by the depth of invasion, the incidence of sm1, sm2, or sm3 was 28.9%, 36.7%, or 34.4% respectively. The incidence of lymph nodes metastasis was 22.2% and it significantly increased as the grade of depth of invasion. This was considered a reason why the lymphatic invasion positive cases increased with an increase in positive lymph node involvement. Conversely there was no lymph nodes metastasis in the sm1 tumors with 20mm or less than in diameter, indentation types macroscopically, or differentiated types histologically. These tumors were considered to be possible candidates for the reduction surgery. Five patients died of cancer recurrence and another five patients died of other disease, the 5-year survival rate being 88.2%. Recurrent cases were significantly frequent in the aged over 70 years old. Postoperative strict observation is necessary for high risk cases of recurrence such as 40mm or more in tumor diameter, differentiated type, deeper invasion than sm2 and multiple gastric cancer.