Effects of single and combined maltose tetrapalmitate immunotherapy, cyclophosphamide chemotherapy and radiotherapy on ethyl carbamate accelerated primary lung cancer in A/J mice.

A/J mice were given ethyl carbamate to accelerate and to raise to 100 percent the incidence of lung tumours at 34 weeks (day 237) of age. The animals were then divided into groups which received the following treatments: group 1, no treatment; group 2, MTP alone; group 3, radiotherapy alone; group 4, cyclophosphamide alone; group 5, radiotherapy + MTP; group 6, MTP + cyclophosphamide; group 7, radiotherapy followed by cyclophosphamide and group 8, MTP and radiotherapy together followed by MTP and cyclophosphamide. Except for radiotherapy, which was given for 5 consecutive days, MTP and cyclophosphamide were continued till the death of the animals. The treatment efficacies were evaluated by the number and size of tumour nodules, taking into consideration the survival time of the animal. Animals in groups receiving cyclophosphamide died earlier (between days 290 and 315) due to its toxic effects, and half of the radiotherapy-MTP were sacrificed at day 314 for comparison. Although cyclophosphamide alone and radiotherapy plus cyclophosphamide demonstrated antitumour activity, the number of tumour nodules and the nodule diameter were reduced most effectively in group 8 (receiving MTP, radiotherapy and cyclophosphamide). Among the animals in the non-cyclophosphamide group, radiotherapy alone was ineffective. MTP given before and after radiotherapy (group 5) kept tumour volume in control although this group died suddenly. The animals receiving only MTP died between day 430 and 470. The number of tumour nodules and the nodule diameter in the MTP group were, however, significantly reduced when compared to controls or radiotherapy group animals dying at or near the same time.