Pseudo-progression and delayed responses can happen

[Olga]

Response of metastatic mucosal melanoma to immunotherapy: It can get worse before it gets better.
http://www.ncbi.nlm.nih.gov/pubmed/26811403
Responses to immune checkpoint inhibitors are usually delayed. An interim progression on restaging computed tomography scans "pseudo-progression" may be observed before response to treatment occur. In this case, we report a significant interim progression of metastatic mucosal melanoma before meaningful responses to immunotherapy occurred. The patient developed significant immune therapy-related colitis and new onset vitiligo. Further restaging computed tomography scans showed sustained tumor response despite stopping the immune therapy.