Synergistic effects of hyperthermia in preoperative radiochemotherapy for rectal carcinoma

We investigated the effectiveness of hyperthermia added to preoperative radiation and chemotherapy for the treatment of rectal carcinoma.

Forty-one patients receiving preoperative radiation were divided into two groups, Group A (20 patients; receiving radiation, hyperthermia, and chemotherapy) and Group B (21 patients, receiving no hyperthermia). Total dose of radiation was 40.5 Gy. Hyperthermia was administered using 8 MHz of radiofrequency. Rectal temperature reached 42 degrees C. A total dose of 3,400 mg of 5-fluorouracil given by suppository was used as the chemotherapeutic agent. Effect of the preoperative treatment was assessed by tumor reduction on barium enema, histologic findings of the resected specimens, area measurement of the residual cancer tissue, and by silver-staining nucleolar organizer region (AgNOR) score.

Tumor reduction on barium enema was significantly greater in Group A than in Group B (P < 0.01). Excluding two cases of mucinous carcinoma because a large acellular mucinous accumulation added materially to the cancerous area, the ratio of residual cancer area to total lesion size in Group A was significantly smaller than in Group B (P < 0.05). AgNOR score of the resected tumor tended to be smaller in Group A than in Group B.

Addition of hyperthermia resulted in a greater degree of tumor necrosis and was considered to be useful as a preoperative treatment for rectal carcinoma.