  Deep learning models have shown a great effectiveness in recognition of
findings in medical images. However, they cannot handle the ever-changing
clinical environment, bringing newly annotated medical data from different
sources. To exploit the incoming streams of data, these models would benefit
largely from sequentially learning from new samples, without forgetting the
previously obtained knowledge. In this paper we introduce LifeLonger, a
benchmark for continual disease classification on the MedMNIST collection, by
applying existing state-of-the-art continual learning methods. In particular,
we consider three continual learning scenarios, namely, task and class
incremental learning and the newly defined cross-domain incremental learning.
Task and class incremental learning of diseases address the issue of
classifying new samples without re-training the models from scratch, while
cross-domain incremental learning addresses the issue of dealing with datasets
originating from different institutions while retaining the previously obtained
knowledge. We perform a thorough analysis of the performance and examine how
the well-known challenges of continual learning, such as the catastrophic
forgetting exhibit themselves in this setting. The encouraging results
demonstrate that continual learning has a major potential to advance disease
classification and to produce a more robust and efficient learning framework
for clinical settings. The code repository, data partitions and baseline
results for the complete benchmark will be made publicly available.
