Cortisol Levels Predict Remission in Cushing’s Patients Undergoing Transsphenoidal Surgery

In patients with Cushing’s disease, removing the pituitary tumor via an endoscopic transsphenoidal surgery (TSS) leads to better remission rates than microscopic TSS, according to new research.

But regardless of surgical approach, plasma cortisol levels one day after surgery are predictive of remission, researchers found.

The study, “Management of Cushing’s disease: Changing trend from microscopic to endoscopic surgery,” was published in the journal World Neurosurgery.

Because it improves visualization and accessibility, endoscopic TSS has been gaining popularity over microscopic TSS to remove pituitary tumors in Cushing’s disease patients. Yet, although this surgery has been associated with high remission rates, whether it outperforms microscopic surgery and determining the factors affecting long-term outcomes may further ease disease recurrence after TSS.

A team with the All India Institute of Medical Sciences addressed this topic in 104 patients who underwent surgery from January 2009 to June 2017. Among these patients, 47 underwent microscopic surgery and 55 endoscopic surgery. At presentation, their ages ranged from 9 to 55 (mean age of 28). Also, patients had been experiencing Cushing’s symptoms over a mean duration of 24 months.

Eighty-seven patients showed weight gain. Hypertension (high blood pressure) and diabetes mellitus were among the most common co-morbidities, found in 76 and 33 patients, respectively. Nineteen patients had osteoporosis and 12 osteopenia, which refers to lower-than-normal bone mineral density.

As assessed with magnetic resonance imaging, 68 patients had a microadenoma (a tumor diameter smaller than one centimeter) and 27 had a macroadenoma (a tumor one centimeter or larger). Only two patients had an invasive pituitary adenoma.

Two patients with larger tumors were operated on transcranially (through the skull). The surgery resulted in total tumor removal in 90 cases (86.5%). A blood loss greater than 100 milliliter was more common with endoscopic than with microscopic TSS.

Ten patients developed transient diabetes inspidus, two experienced seizures after surgery, and six of nine patients with macroadenoma and visual deterioration experienced vision improvements after TSS.

The incidence of intraoperative leak of cerebrospinal fluid — the liquid surrounding the brain and spinal cord — was 23.2%, while that of post-operative leak was 7.7% and was more common in microadenoma than macroadenoma surgery (9.8% vs. 5.0%).

Seventeen patients were lost to follow-up and two died due to metabolic complications and infections. The average follow-up was shorter for endoscopic than with microscopic surgery (18 months vs. 35 months).

Among the remaining 85 cases, 65 (76.5%) experienced remission, as defined by a morning cortisol level under 5.0 μg/dL, restored circadian rhythm (the body’s internal clock, typically impaired in Cushing’s patients), and suppression of serum cortisol to below 2 μg/dl after overnight dexamethasone suppression test.

The remission rate was 54.5% in pediatric patients and was higher with endoscopic than with microscopic TSS (88.2% vs. 56.6%). Also, patients with microadenoma showed a trend toward more frequent remission than those with macroadenoma (73.2% vs. 64.3%).

Ten of the remaining 20 patients experienced disease recurrence up to 28 months after surgery. Sixteen cases revealed signs of hypopituitarism, or pituitary insufficiency, which were managed with replacement therapy.

A subsequent analysis found that morning cortisol level on day one after surgery was the only significant predictor of remission. Specifically, a one-unit increase in cortisol lowered the likelihood of remission by 7%. A cortisol level lower than 10.7 μgm/dl was calculated as predicting remission.

Overall, the study showed that “postoperative plasma cortisol level is a strong independent predictor of remission,” the researchers wrote, and that “remission provided by endoscopy is significantly better than microscopic approach.”

From https://cushingsdiseasenews.com/2019/09/24/cortisol-levels-predict-remission-cushings-patients-undergoing-transsphenoidal-surgery/

The Challenge of Obesity in Diagnosing Cushing’s Syndrome and Strategies to Improve Methods

The effects of obesity on the diagnosis of Cushing’s syndrome and strategies to alter the traditional approaches have been addressed in a new review study.

The study, “Diagnosis and Differential Diagnosis of Cushing’s Syndrome,” appeared in The New England Journal of Medicine. The author was Dr. Lynn D. Loriaux, MD and PhD, and a professor of medicine at the Division of Endocrinology, Diabetes and Clinical Nutrition at the School of Medicine, Oregon Health & Science University (OHSU), in Portland, Oregon.

Traditionally, exams of patients with glucocorticoid excess focused on the presence of changes in anabolism (the chemical synthesis of molecules). Given the increase in obesity in the general population, changes in anabolism can no longer distinguish Cushing’s syndrome from metabolic syndrome.

However, analyses of anti-anabolic changes of cortisol – including osteopenia (lower bone density), thin skin, and ecchymoses (injury that causes subcutaneous bleeding) – are an effective way to make this distinction.

The worldwide prevalence of metabolic syndrome in obese people is estimated at about 10%. Conversely, the incidence of undiagnosed Cushing’s syndrome is about 75 cases per 1 million people.

Cushing’s and metabolic syndrome share significant clinical similarities, including obesity, hypertension, and type 2 diabetes. Therefore, “making the diagnosis is the least certain aspect in the care of patients with [Cushing’s],” Loriaux wrote.

Regarding a physical examination, patients with osteoporosis, reduced skin thickness in the middle finger, and three or more ecchymoses larger than 1 cm in diameter and not associated with trauma are more likely to have Cushing’s. Researchers estimate the probability of people with all three of these symptoms having Cushing’s syndrome is 95%.

Measuring 24-hour urinary-free cortisol levels allows the assessment of excess glucocorticoid effects, typical of Cushing’s syndrome. The test, which should be done with the most stringent techniques available, averages the augmented secretion of cortisol in the morning and the diminished secretion in the afternoon and at night.

Dexamethasone suppression is one of the currently used screening tests for Cushing’s syndrome. Patients with obesity and depression should not show decreased plasma cortisol levels when dexamethasone is suppressed. However, given its low estimated predictive value (the proportion of positive results that are “true positives”), “this test should not influence what the physician does next and should no longer be used” to screen for Cushing’s, the author wrote.

Some patients may show evidence of Cushing’s syndrome at a physical examination, but low urinary free cortisol excretion. This may be due to glucocorticoids being administered to the patient. In this case, the glucocorticoid must be identified and discontinued. Periodic Cushing’s assessments that measure urinary free cortisol should be performed.

The opposite can also occur: no clinical symptoms of Cushing’s, but elevated urinary free cortisol excretion and detectable plasma levels of the hormone corticotropin. In these patients, the source of corticotropin secretion, which can be a tumor or the syndrome of generalized glucocorticoid resistance, must be determined.

The disease process can be corticotropin-dependent or independent, depending on whether the hormone is detectable. Corticotropin in Cushing’s syndrome can come from the pituitary gland (eutopic) or elsewhere in the body (ectopic).

Loriaux recommends that the source of corticotropin secretion be determined before considering surgery. Up to 40% of patients with pituitary adenomas have nonfunctioning tumors (the tumor does not produce any hormones) and the corticotropin source is elsewhere. If misdiagnosed, patients will likely undergo an unnecessary surgery, with a mortality rate of 1%.

Patients with an ectopic source of corticotropin should undergo imaging studies in the chest, followed by abdominal and pelvic organs. If these tests fail to detect the source, patients should undergo either the blockade of cortisol synthesis or an adrenalectomy (removal of adrenal glands).

However, corticotropin-independent Cushing’s is usually caused by a benign adrenal tumor that uniquely secretes cortisol.

“Such tumors can be treated successfully with laparoscopic adrenalectomy,” Loriaux wrote. If the tumor secretes more than one hormone, it is likely malignant. Surgical to remove the tumor and any detectable metastases should be conducted.

Overall, “the treatment for all causes of [Cushing’s syndrome], other than exogenous glucocorticoids, is surgical, and neurosurgeons, endocrine surgeons, and cancer surgeons are needed,” Loriaux wrote in the study.

“This level of multidisciplinary medical expertise is usually found only at academic medical centers. Thus, most, if not all, patients with [Cushing’s syndrome] should be referred to such a center for treatment.”

From https://cushingsdiseasenews.com/2017/10/24/diagnosing-cushings-syndrome-amid-challenge-of-obesity-and-strategies-to-improve-methods/

GH therapy increases fracture risk in patients previously treated for acromegaly

van Varsseveld NC, et al. Pituitary. 2016;doi:10.1007/s11102-016-0716-3.

Adult patients with severe growth hormone deficiency previously treated for acromegaly saw an increased fracture risk after 6 years of growth hormone replacement therapy, whereas those previously treated for Cushing’s disease did not experience the same risk, according to a recent observational study.

Nadege C. van Varsseveld, MD, of the department of internal medicine at VU University Medical Center in Amsterdam, and colleagues analyzed data from 1,028 patients with previous nonfunctioning pituitary adenoma (NFPA; n = 783), acromegaly (n = 65) and Cushing’s disease (n = 180), identified through the Dutch National Registry of Growth Hormone Treatment in Adults, a nationwide, long-term surveillance study in patients with severe GH deficiency. Data were collected biannually from medical records through 2009. Baseline DXA measurements were available for 414 patients; 71 (17.1%) had osteoporosis at one or more of the measured sites; 147 (35.5%) had osteopenia.

During a mean follow-up of 5.2 years, researchers found that 166 of patients with previous NFPA were prescribed osteoporosis medications (21.3%), as were 69 patients with previous Cushing’s disease (38.5%) and 22 patients with previous acromegaly (33.4%). During follow-up, 39 patients experienced fractures (3.8%; 32 experiencing one fracture), including 26 patients in the previous NFPA group, eight patients in the previous Cushing’s disease group and five patients in the previous acromegaly group. The median time between baseline and first fracture was 2.4 years (mean age, 59 years).

Researchers found that fracture risk did not differ between groups before 6 years’ follow-up. Fracture risk increased in patients with previous acromegaly after 6 years’ follow-up, but not for those with previous Cushing’s disease vs. patients with NFPA. Results persisted after adjustment for multiple factors, including sex, age, fracture history and the extent of pituitary insufficiency.

The researchers noted that patients with previous Cushing’s disease were younger and more often women and had a greater history of osteopenia or osteoporosis, whereas patients with acromegaly had a longer duration between tumor treatment and the start of GH therapy and were treated more often with radiotherapy.

“During active acromegaly, increased bone turnover has been observed, but reported effects on [bone mineral density] are heterogeneous,” the researchers wrote. “It is postulated that cortical BMD increases, whereas trabecular BMD decreases or remains unaffected.

“The increased fracture risk in the present study may be a long-term effect of impaired skeletal health due to previous GH excess, even though this was not reflected by an increased occurrence of osteopenia or osteoporosis in the medical history,” the researchers wrote. – by Regina Schaffer

Disclosure: One researcher reports receiving consultancy fees from Novartis and Pfizer.

From http://www.healio.com/endocrinology/hormone-therapy/news/online/%7B92a67ad7-3bd5-46f0-b999-0a8e3486edab%7D/gh-therapy-increases-fracture-risk-in-patients-previously-treated-for-acromegaly

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