http://www.ncbi.nlm.nih.gov/pubmed/9541678This is from 1998. Not sure what newer research has been done but a quick internet search turned this up.
CONCLUSIONS:
For some tumors, cisplatin appears to be superior to carboplatin in terms of therapeutic effectiveness (germ cell tumors, bladder cancer, head and neck cancer), while for others, effectiveness is comparable (lung cancer, ovarian cancer). Toxicity profiles are distinctly different for the two analogues however, generally favoring carboplatin. The issue of potential carboplatin underdosing related to the lack of physiologic dose calculations (utilizing the AUC [area under the curve] method) in the comparative trials of cis- versus carboplatin is probably not clinically important since a dose response effect has not been established for carboplatin or for cisplatin. The selection of the optimal platinum analogue to be employed is dependent on the type of tumor, the treatment intention (palliative vs. curative) and the other component drugs being used in combination.