Joji Kato

Autoradiographic evaluation of 99mTc-methylene diphosphonate accumulation in oral cancer invading the mandible

PURPOSE Skeletal scintigraphy, a sensitive diagnostic tool used to detect changes in bone, is helpful for evaluating bone invasion by oral cancer. However, the exact sites of accumulation of 99mTc-phosphate compounds in the mandible have not yet been fully elucidated. The aim of this study was to determine the localization of 99mTc-methylene diphosphonate (MDP) in the areas of mandible that have been invaded by cancer. PATIENTS AND METHODS Seven patients with oral cancer (lower gingiva, 4; tongue, 2; floor of the mouth, 1) who underwent surgical treatment with mandibular bone resection were included in the study. Autoradiography and contact macroradiography were used for evaluation of 99mTc-MDP accumulation. RESULTS Radioactivity reflecting accumulation of 99mTc-MDP was documented encircling the portion of the mandible with cancerous invasion, suggesting that 99mTc-MDP accumulated in immature bone. High uptake also was found in the periosteal reactive bone around the cortical bone. CONCLUSIONS The amount of increased 99mTc-MDP circumscribing carcinoma invasion varies among cases. Additionally, uptake may not correspond directly with the amount of the carcinoma invasion; that seen in periosteal bone could be attributed mistakenly to bone invasion in planar scintigraphy.

Experimental analysis of the chemically induced carcinoma. The 1st experiment. 1. Gross and microscopic observation, postulated the two range passway for the carcinoma.

This chemically induced carcinogenesis experiment was performed for purposes of preliminary experimenting for further oral carcinoma studies. Painting 0.5% DMBA in liquid paraffin into six-week-old Golden Syrian Hamsters buccal pouches, threetimes a week for 14 weeks, the following results were elucidated.Within the first 4 weeks, inflammatory reactions of the mucosa, i. e., redness, formation of plaques, and bleeding were found. Thereafter, they naturaly disappeared from around the 5th to the 6 th experimental weeks. On the 8 th week, papillomatous tumors suddenly appeared which were growing gradually in size, number, and even in atypism. The surrounding epithelia showed changes comparable to epithelial dysplasia or carcinoma in situ. It was from the 12-week-painted group that well-differentiated squamous cell carcinomas were-first recognized.These tumors were rather exophytic growths and showed a minimal invasive trend. However, invasive tumors were formed as well in the 14-week-painted group. Therefore, two possible ways for carcinoma formation might be suggested. One is from papilloma through increased atypism, such as verrucous carcinoma, and the other from epithelial dysplasia or carcinoma in situ with downward growth of the rete-processes to the carcinoma.