medwireNews: Children with Cushing’s disease who have a negative magnetic resonance imaging (MRI) pituitary scan are less likely to achieve remission after surgery than those with a confirmed tumour, say researchers.
However, they also found that those with negative MRI scans who achieved remission were no more likely than those with positive scans to experience recurrence in the longer term.
“This suggests that if the operation is successful and the neurosurgeon resects the tumour, the risk for long-term recurrence is similar as in patients with a visualised tumour”, the team writes in Clinical Endocrinology.
Constantine Stratakis (Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland, USA) studied data from 186 patients with Cushing’s disease who were younger than 21 years at presentation.
They found that 31.7% of this cohort did not have MRI findings that were suggestive of a pituitary adenoma, which they say is consistent with previous research.
They also note the finding is “not unexpected since most pituitary adenomas are small”.
In this study, the median size as calculated after surgical resection was significantly smaller in children with negative than positive MRIs, at 4 versus 5 mm.
Children with negative MRI findings were younger than those with positive scans, at a median of 11.1 versus 14.4 years. They also had significantly lower median levels of morning cortisol, at 429 versus 510 nmol/L, and of adrenocorticotropin, at 7.24 versus 10.4 pmol/L.
“This may imply that these patients are identified earlier in the course of their disease, although this hypothesis is not confirmed based on the disease duration as extrapolated by medical records”, say Stratakis and team.
Of the 181 children with postoperative data, 14.9% did not achieve remission after their first surgical intervention. Thirteen of these 27 patients had a second operation within 3 weeks of their first procedure, with 11 achieving remission.
Children with a positive MRI scan were a significant 2.6 times more likely to achieve remission after surgery than those with a negative scan, and this remained true after adjusting for the neurosurgeon who performed the resection.
However, during a median follow-up of 15.8 months, the likelihood of children experiencing recurrence did not significantly differ according to whether they had positive or negative MRI scans, at rates of approximately 35% versus 55%.
The researchers stress that the non-remission and recurrence rates are not representative of a general paediatric Cushing’s disease cohort, because they were influenced by difficult-to-treat patients referred to their specialist centre.
“The possibility of a negative MRI should constitute an important part of the discussion with the patient and the family during the workup”, the team concludes.
“In our experience, a negative MRI often increases the family’s anxiety which may delay further testing often required, such as [bilateral inferior petrosal sinus sampling]. To prepare families and patients, we often discuss in advance that a negative MRI is not uncommon, and we have additional strategies in confirming the diagnosis in these patients.”
By Eleanor McDermid
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