Abstract
Inbred animal tumor models with artificially induced tumors are inadequately comparable with human neoplasias. Thus, cows with squamous cell carcinomas developing spontaneously in the head and neck region were used for experimental investigations on the immunotherapy of malignant tumors. This experimental model served to investigate the therapeutic effect of a single intratumoral application of bacille Calmette‐Guerin (BCG) cell‐wall preparations (CWP) in comparison to local and radical surgical procedures. One hundred twenty‐nine tumor‐bearing cows were divided into 5 groups. Group 1 received a single intratumoral injection of BCG‐CWP. The procedures in Groups 2 and 3 involved local (primary tumor) and radical (primary tumor and draining lymph nodes) surgery, respectively. A procedure was developed for the radical operation in accordance with the method used for radical neck dissection in patients with head and neck tumors. Group 4 remained untreated and Group 5 received sham (improperly compounded) BCG‐CWP. Twenty‐six percent of the animals treated with BCG‐CWP, and 52% treated with local surgery, were clinically tumor free 2.5 years after treatment, while none of those that had undergone radical surgery showed any evidence of tumor recurrence. In the control groups (Groups 4 and 5), progressive tumor growth was characteristic for all except one animal that had spontaneous remission. The favorable outcome of BCG‐CWP treatment in a bastard animal population with spontaneously developing squamous cell carcinomas in the head and neck region may possibly be attributed to the fact that this experimental system involves a tumor with very marked tumor‐specific transplantation antigens. The successful experimental results obtained with BCG‐CWP therapy have led to a prospective, randomized study in patients with squamous cell carcinomas in the head and neck region.