What oncologic emergency is most likely to result from abrupt discontinuation of long-term glucocorticoids?

The most likely oncologic emergency resulting from abrupt discontinuation of long-term glucocorticoids is an adrenal crisis. Glucocorticoids, such as prednisone, are synthetic versions of cortisol, a hormone produced by the adrenal glands. When patients are on prolonged glucocorticoid therapy, the body reduces its own production of cortisol due to the negative feedback mechanism. If glucocorticoids are suddenly stopped, the adrenal glands may not be able to compensate quickly enough to produce adequate amounts of cortisol. This can lead to an adrenal crisis, characterized by severe fatigue, hypotension, hypoglycemia, and electrolyte imbalances.

This situation is particularly critical in patients who have been on high doses of glucocorticoids for an extended period, as their adrenal glands may become severely atrophied and less responsive. Understanding this physiological response is essential for preventing an adrenal crisis when managing patients on long-term glucocorticoid therapy.