J.Jpn. Surg. Soc.. 81(7): 608-615, 1980
Original article
EXPERIMENTAL STUDIES ON CRYOIMMUNIZATION IN THE METASTASIZING RATS MAMMARY TUMOR, MRMT-1
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*) 2nd Department of Surgery, Gifu University School of Medicine (Director: Prof. Kazuki Sakata) Atsushi Misao*), Shigetoyo Saji, Koziro Matsumura, Hiromi Tanemura, Tokuro Kunieda, Kazuki Sakata |
1) The longest tumor-bearing period, during which cryosurgical treatment (fast frozen at －170℃ and slow thawing at room temperature) by 3 cycle-method was effective, was 7 days, when the tumor had grown up to 12 to 18 mm in diameter and 3.0 g or less in weight. Local recurrence rate following cryosurgery on the 7th day of tumor-bearing was similar as that following surgical excision.
2) Results of cryosurgery by 3 cycle-method and of surgical excision in rats bearing the tumor for 7 days were examined and compared with each other, as described below.
3) Local recurrence rates were 11.8 and 11.4% in cryosurgery and the surgical excision groups respectively, showing no significant difference.
Mortality rates in the locally cured cases were 8.3 and 5.4% in the cryosurgery and the surgical excision groups respectively, showing no significant difference. Average survival periods in these cases were 81.3 and 67.5 days in both groups respectively, showing some prolongation in the cryosurgery groups. The lung metastases were seen in 100% of the both groups, whereas incidence of lymph node metastases was higher in the cryosurgery group than in the surgery group.
4) Resistance to challenge in the locally cured cases showed the following findings.
In the cryosurgery group, the resistance rose to a peak at 10 weeks after the treatment, whereas the resistance was relatively high at the early postoperative stage in the surgery group.
5) In axillary lymph node, germinal center hyperplasia was significantly increased in the cryosurgery group as compared with the surgical excision group. Sinus histiocytosis showed a similar tendency.
6) The results obtained in the present investigation suggest that cryo-immunization does exist, but its anti-tumor activity is weak and, under some condition of freezing-thawing, may possibly exert an adverse immunological effect on tumor growth.
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