  Recently, we have proposed a nutrient-limited model for the avascular growth
of tumors including cell proliferation, motility and death \cite{jr}, that,
qualitatively reproduces commonly observed morphologies for carcinomas {\it in
situ}. In the present work, we analyze the effects of distinct chemotherapeutic
strategies on the patterns, scaling and growth laws obtained for such
nutrient-limited model. Two kinds of chemotherapeutic strategies were
considered, namely, those that kill cancer cells and those that block cell
mitosis but allows the cell to survive for some time. Depending on the
chemotherapeutic schedule used, the tumors are completely eliminated, reach a
stationary size or grow following power laws. The model suggests that the
scaling properties of the tumors are not affected by the mild cytotoxic
treatments, although a reduction in growth rates and an increase in
invasiveness are observed. For the strategies based on antimitotic drugs a
morphological transition in which compact tumors become more fractal under
aggressive treatments was seen.
