Recurrent ovarian cancer: how important is it to treat to disease progression?

Ovarian cancer is increasingly recognized as a chronic disease whose treatment is often characterized by administration of multiple, sequential active agents, each of which may or may not be accompanied by a tumor response. Despite the large proportion of patients who relapse and undergo longer-term treatment, the question of optimal treatment duration has not been fully addressed to date. For patients who progress on therapy, the answer is straightforward: they are switched to another active agent, presumably having a different mechanism of action from previous therapies with, ideally, limited overlapping toxicities. However, for patients who remain in partial response or who have stable disease, the answer is less apparent and less clear. The majority of oncologists believe that treatment beyond 6 cycles of a given therapy does not provide any additional benefit to patients. There are some data to support that treatment strategy. However, with the advent of new, less toxic agents, treatment to progression should be further explored. Agents that are potentially well suited for extended treatment intervals may include such properties as absence of cumulative toxicity, non-cross-resistance, positive benefit on quality of life, and convenient schedule. A number of active agents in ovarian cancer (platinum, paclitaxel, topotecan, liposomal doxorubicin, docetaxel, gemcitabine, and etoposide) will be reviewed in the context of what is known about cumulative toxicity, potential adverse effects on patients' quality of life, and evidence addressing the potential benefits of longer-term treatment.