Introduction

During the 1970s and 1980s, when it became increasingly clear that intense pain had long been an underrecognized and poorly treated manifestation of cancer, it became apparent that cancer patients commonly experience intermittent exacerbations of severe pain against a background of continuous, or baseline, pain (1,2). On the heels of the World Health Organization analgesic ladder approach to general pain control, this recognition led to treatment guidelines and patient care manuals recommending management of these episodic pains as routine practice (3–9).

The term breakthrough pain (BTP) can be found in the pain management literature starting about a decade ago (10–14). An operational definition was offered at that time by Portenoy and Hagen (15), who suggested that “breakthrough pain … refers generally to a transitory exacerbation of pain that occurs on a background of otherwise stable pain in a patient receiving chronic opioid therapy.” This definition seems to have gained wide-spread acceptance, with only minimal (published) debate as to its overall accuracy or utility (16).

Evidence that BTP, at the very least, has become recognized as an important aspect of overall cancer care can be found on two fronts. First, a growing number of review articles and practice recommendation guidelines on this subject have been published in recent years. They affirm the view that BTP needs to be evaluated and treated as part of the overall cancer pain management plan (17–29). In addition, reports of analgesic clinical trials for the management of cancer pain have begun to routinely incorporate a treatment arm for BTP in the methodology (30–37).