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Growth rate predicts need for secondary treatment in nonfunctioning pituitary adenomas
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The need for secondary treatment in adults with surgically resected nonfunctioning pituitary adenomas may be predicted by the presence of residual tumor, growth rate and location, according to findings published in Clinical Endocrinology.
Ken K.Y. Ho, MBBS, MS, FRACS, chair of the Centres for Health Research at Princess Alexandra Hospital in Australia, and colleagues evaluated 108 adults (58 men) who had surgically resected nonfunctioning pituitary adenomas to identify predictors for secondary therapy after resection. Median follow-up was 5.7 years; 56 participants were followed beyond 5 years, and 19 were followed beyond 10 years.
Researchers reviewed 445 MRI images, including 75 preoperative and 370 postoperative scans.
After surgery, tumor volume was reduced by 80% from a median 3,340 mm3 to 608 mm3, and 39% of participants had no remnant tumor tissue. In those who did have remnant tumor tissue, 27% did not grow; there was a median growth rate of 66 mm3 per year in the 73% of remnant tumors that did grow.
Overall, 22% of participants required further treatment, including irradiation (13%) and surgery (9%). Compared with participants who did not require secondary therapy, participants who required secondary therapy were imaged more frequently (P = .01), undertook more scans (P = .03) and had shorter overall duration of follow-up (P = .01). Participants who required secondary therapy had 80% greater median preoperative tumor volume compared with participants who did not require secondary treatment. Growth rate was nearly 10 times as fast in participants who received secondary treatment compared with those who did not. Later treatment was predicted with 94% sensitivity and 83% specificity by tumors that grew by at least 80 mm3 per year. Later therapy was more likely in tumors with a remnant growth rate of more than 80 mm3 per year compared with those with a growth rate of less than 80 mm3 per year (HR = 8.1; 95% CI, 2.4-27.3). Further therapy was six times more likely with a remnant location in the suprasellar region compared with those located in the sella (HR = 6.1; 95% CI, 1.1-32).
“Following surgical resection of [nonfunctioning pituitary adenomas], patients without an initial identifiable remnant or with a slow-growing remnant are unlikely to require further treatment,” the researchers wrote. “Further treatment was required six to eight times more frequently for fast-growing remnants and those located in the suprasellar area. [Growth rates] are relatively constant over time. Proliferative indices were positive in only a small minority of patients but appear to have good positive predictive value. However, their absence did not rule out later treatment. Overall, the histological characteristics of the tumor did not influence outcome in this study.” – by Amber Cox
Disclosures: The researchers report no relevant financial disclosures.
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