Pitfalls in early biochemical evaluation after transsphenoidal surgery in patients with acromegaly

May the SAGIT® instrument be used as a preoperative prognostic tool in patients with acromegaly?

BACKGROUND

The SAGIT® instrument has been developed for acromegaly to assist clinicians in staging the disease accurately, assessing the response to therapy, and adjusting the treatment. We aimed to evaluate the preoperative utility of the SAGIT® instrument and to discover a cut-off value for predicting the surgery outcome and long-term prognosis of patients with acromegaly.

METHODS

A total of 832 patients with acromegaly were identified from the medical record system. Acromegaly diagnosis was confirmed by elevated IGF-1 levels according to the age-adjusted upper limit of normal, lack of suppression of GH concentration to <0.4 µg/L following a 75 g oral glucose tolerance test, and the existence of a pituitary adenoma demonstrated by MRI. The SAGIT® instrument comprises five key components of acromegaly: signs and symptoms (S), associated comorbidities (A), GH levels (G), IGF-1 levels (I), and the features of the tumor (T). The initial postoperative remission was evaluated 3 months after surgery.

RESULTS

A final cohort of 132 patients has been included in our study. Median preoperative SAGIT scores were significantly different (10.00 [9.00-11.00] to 11.00 [10.00-13.00], [P=0.002]) between patients who achieved initial remission at 3 months and those who were not in remission. The threshold SAGIT score distinguishing between initial remission and nonremission groups was 10 with an AUC of 0.660 (P<0.001).

CONCLUSIONS

In our retrospective cohort study, the findings suggested that the SAGIT® instrument may be a beneficial preoperative tool to predict the initial remission postoperatively and long-term prognosis of the patients with acromegaly.

Predictors of biochemical remission after transsphenoidal surgery in a large cohort of acromegaly patients

PURPOSE

The objective of this study was to characterize the clinical characteristics and factors predictive of biochemical remission in patients with symptomatic acromegaly undergoing transsphenoidal surgery (TSS) at an academic tertiary care center, as defined by the 2022 Acromegaly Consensus Conference guidelines.

METHODS

In this single institution, longitudinal, retrospective study, a large cohort of 158 patients with a preoperative diagnosis of acromegaly undergoing surgery at a large, academic, tertiary care center were examined. We excluded 38 patients as IGF-1 testing was performed less than 12 weeks postoperatively.

RESULTS

The majority of tumors were intrasellar macroadenomas (75%), receiving endoscopic surgery (98.3%). Patients who failed remission appeared to have higher raw IGF-1 levels preoperatively (732 ± 313 ng/mL) compared to those who attained remission (278 ± 313 ng/mL), and trended towards higher rates of GH hypersecretion (93.1% vs. 78.4%). Patients failing remission had higher GH levels and IGF-1 levels postoperatively and experienced a lower percentage reduction in raw IGF-1 levels. Multivariable logistic regression demonstrated that the magnitude of preoperative IGF-1 (OR: 1.001, 95% CI: 1.00, 1.003) and the percentage change in IGF-1 (OR: 1.021, 95% CI: 1.01, 1.04) were predictive of remission failure. Radiographic characteristics such as tumor size, suprasellar extension, and location were not necessarily predictive of worse postoperative outcomes.

CONCLUSIONS

Lesions which failed to achieve biochemical remission appeared to display distinctive preoperative endocrinological characteristics, with preoperative IGF-1 levels and percentage changes in IGF-1 levels being predictive of biochemical remission status.

Self-reported symptoms in patients with acromegaly: a 6-month follow-up in a single neurosurgical center

Acromegaly is characterized by hypersecretion of growth hormone (GH) and insulin-like growth factor 1 (IGF-1), accompanied by a compromise in the perception of wellness. The Patient-Assessed Acromegaly Symptom Questionnaire (PASQ) is relevant to assessing signs and symptoms but is mainly used to evaluate the efficacy of a pharmacological intervention. To explore the perioperative variation in symptom severity, the divergence between subgroups stratified according to clinical outcomes or treatment modalities, and the interaction between symptom scores and clinical indices, we prospectively recruited 106 patients with acromegaly from 2016 to 2018. Oral glucose tolerance and GH tests were performed, and PASQ was administered before treatment and 6 months postoperatively. Patients were divided into active (n = 49) and remission (n = 57) groups according to postoperative GH and IGF-1 levels. PASQ scores and GH and IGF-1 levels decreased significantly postoperatively in both groups. A significantly higher preoperative headache score and greater extent of decrease in arthralgia were seen in the active and remission groups, respectively. No significant variation in PASQ scores was found between patients receiving surgery alone and those receiving preoperative somatostatin analogs. Preoperative fasting GH (GH0) levels were positively correlated with preoperative excessive perspiration. Further regression analyses validated the variation in GH0 as a noteworthy determinant of the extent of change in soft-tissue swelling, excessive perspiration, fatigue, and total PASQ scores. Patient-reported symptoms were substantially alleviated after surgery, independent of endocrine remission or use of preoperative somatostatin. A GH level decrease was a notable coefficient for PASQ scores.

The Prognostic-Based Approach in Growth Hormone-Secreting Pituitary Neuroendocrine Tumors (PitNET): Tertiary Reference Center, Single Senior Surgeon, and Long-Term Follow-Up

Postoperative deserved outcomes in acromegalic patients are to normalize serum insulin-like growth factor (IGF-1), reduce the tumoral mass effect, improve systemic comorbidities, and reverse metabolic alterations. Pituitary neuroendocrine tumors (PitNET) are characterized to present a heterogeneous behavior, and growth hormone (GH)-secreting PitNET is not an exception. Promptly determining which patients are affected by more aggressive tumors is essential to guide the optimal postoperative decision-making process [prognostic-based approach]. From 2006 to 2019, 394 patients affected by PitNET were intervened via endoscopic endonasal transsphenoidal approach by the same senior surgeon. A total of 44 patients that met the criteria to be diagnosed as acromegalic and were followed up at least for 24 months (median of 66 months (26-156) were included in the present study. Multiple predictive variables [age, gender, preoperative GH and IGF-1 levels, maximal tumor diameter, Hardy's and Knosp's grade, MRI. T2-weighted tumor intensity, cytokeratin expression pattern, and clinicopathological classification] were evaluated through uni- and multivariate statistical analysis. Sparse probability of long-term remission was related to younger age, higher preoperative GH and- or IGF-1, group 2b of the clinicopathological classification, and sparsely granulated cytokeratin expression pattern. Augmented recurrence risk was related to elevated preoperative GH levels, tumor MRI T2-weighted hyperintensity, and sparsely granulated cytokeratin expression pattern. Finally, elevated risk for reintervention was related to group 2b of the clinicopathological classification, Knosp's grade IV, and tumor MRI T2-weighted hyperintensity. In this study, the authors determined younger age, higher preoperative GH and- or IGF-1 levels, group 2b of the clinicopathological classification, Knosp's grade IV, MRI T2-weighted tumor hyperintensity and sparsely granulated cytokeratin expression pattern are related to worse postoperative outcomes in long-term follow-up patients affected with GH-secreting PitNET.

First but not second postoperative day growth hormone assessments as early predictive tests for long-term acromegaly persistence

PURPOSE

Postoperative assessment of acromegaly activity is typically performed at least 3 months after neurosurgery (NS). Few studies have evaluated the use of early postoperative growth hormone (GH) levels as a test to predict short- and long-term remission of acromegaly. Our objective was to evaluate the diagnostic performance of serum random GH on a postoperative day one (D1-rGH) and two (D2-rGH), particularly in predicting long-term disease persistence.

MATERIALS AND METHODS

Forty-one subjects with acromegaly who were undergoing NS were enrolled (mean age ± SD 47.4 ± 13.1 years at diagnosis; women 54%; macroadenomas 71%). The final assessment of disease activity was performed one year after NS. ROC curves were used to evaluate the diagnostic performance of D1-rGH and D2-rGH.

RESULTS

After a 1-year follow-up, the overall remission rate was 55%. ROC analysis identified an optimal D1-rGH cut-off value of 2.1 ng/mL for diagnosing long-term disease persistence (55.6% SE; 90.9% SP). The cut-off point became 2.5 ng/mL after maximizing specificity for disease persistence (yielding a 100% positive predictive value) and 0.3 ng/mL after maximizing sensitivity for disease remission. The optimal D2-rGH cut-off value was 0.6 ng/mL (81.8% SE; 50% SP); the cut-off point became 2.9 ng/mL after maximizing specificity and 0.1 ng/mL after maximizing sensitivity, with no clinical utility.

CONCLUSIONS

D1-rGH could be a highly specific test for the early diagnosis of long-term acromegaly persistence, which is predicted by a value > 2.5 ng/mL with a great degree of certainty. The diagnostic performance of D2-rGH was insufficient. Further research is required to validate these preliminary results prior to modifying the postoperative management of acromegaly.

Early postoperative prediction of both disease remission and long-term disease control in acromegaly using the oral glucose tolerance test

PURPOSE

Transsphenoidal surgery (TSS) is the cornerstone of acromegaly treatment. Two biochemical parameters, growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels, sometimes diverge postoperatively; however, it is important to maintain disease control without further treatment, regardless of whether these parameters converge. This study investigated whether remission and long-term disease control could be predicted using early postoperative GH and IGF-1 levels.

METHODS

We reviewed 36 consecutive surgically treated patients with acromegaly. IGF-1 levels and minimum GH levels during an oral glucose tolerance test (OGTT) were evaluated at 2 weeks, as well as at 3 months postoperatively. After comparison between the remission and nonremission groups, we analyzed whether early postoperative parameters could predict remission and long-term disease control.

RESULTS

Twenty-five patients (69.4%, Group A) achieved remission within 1 year postoperatively. Of the remaining patients (median follow-up period, 53 months), seven (19.5%, Group B) maintained normal IGF-1 levels without treatment, whereas four (11.1%, Group C) required additional treatment. GH levels <1.5 ng/mL measured on the morning after surgery and nadir GH levels <0.7 ng/mL during the OGTT conducted at 2 weeks postoperatively were predictive of remission, with the latter demonstrating 95.2% sensitivity and 100% specificity. All group C patients had nadir GH levels ≥0.7 ng/mL during the OGTT and IGF-1 levels ≥SD +3 at 2 weeks postoperatively.

CONCLUSION

Early postoperative nadir GH levels during the OGTT and IGF-1 levels at 2 weeks postoperatively demonstrated excellent predictive value for both endocrinological remission and the necessity for additional treatment.

Machine learning in predicting early remission in patients after surgical treatment of acromegaly: a multicenter study

PURPOSE

Accurate prediction of postoperative remission is beneficial for effective patient-physician communication in acromegalic patients. This study aims to train and validate machine learning prediction models for early endocrine remission of acromegalic patients.

METHODS

The training cohort included 833 patients with growth hormone (GH) secreting pituitary adenoma from 2010 to 2018. We trained a partial model (only using pre-operative variables) and a full model (using all variables) to predict off-medication endocrine remission at six-month follow-up after surgery using multiple algorithms. The models were validated in 99 prospectively collected patients from a second campus and 52 patients from a third institution.

RESULTS

C-statistic and the accuracy of the best partial model was 0.803 (95% CI 0.757-0.849) and 72.5% (95% CI 67.6-77.5%), respectively. C-statistic and the accuracy of the best full model was 0.888 (95% CI 0.861-0.914) and 80.3% (95% CI 77.5-83.1%), respectively. The c-statistics (and accuracy) of using only Knosp grade, total resection, or postoperative day 1 GH level as the single predictor were lower than our partial model or full model (p < 0.001). C-statistics remained similar in the prospective cohort (partial model 0.798, and full model 0.903) and in the external cohort (partial model 0.771, and full model 0.871). A web-based application integrated with the trained models was published at  https://deepvep.shinyapps.io/Acropred/ .

CONCLUSION

We developed and validated interpretable and applicable machine learning models to predict early endocrine remission after surgical resection of a GH-secreting pituitary adenoma. Predication accuracy of the trained models were better than those using single variables.

Prognostic factors of biochemical remission after transsphenoidal surgery for acromegaly: a structured review

PURPOSE

Biochemical control is the main determinant of survival, clinical manifestations and comorbidities in acromegaly. Transsphenoidal selective adenomectomy (TSA) is the initial treatment of choice with reported biochemical remission rates varying between 32 and 85%. Understanding the limiting factors is essential for identification of patients who require medical treatment.

METHODS

We reviewed the English literature published in Medline/Pubmed until Dec 31, 2019 to identify eligible studies that described outcomes of TSA as primary therapy and performed analyses to determine the main predictors of remission.

RESULTS

Most publications reported single-institution, retrospective studies. The following preoperative parameters were consistently associated with lower remission rates: cavernous sinus invasion by imaging, larger tumor size and higher GH levels. Young age and preoperative IGF-1 levels were predictive in some studies. When controlled for covariates, the best single preoperative predictor was cavernous sinus invasion, followed by preoperative GH levels. Conversely, low GH level in the first few days postoperatively was a robust predictor of durable remission. The influence of tumor histology (sparsely granular pattern, co-expression of prolactin and proliferation markers) on surgical remission remains to be established. Few studies developed predictive models that yielded much higher predictive values than individual parameters.

CONCLUSION

Surgical outcome prognostication systems could be further generated by machine learning algorithms in order to support development and implementation of personalized care in patients with acromegaly.

Surgical management of growth hormone-secreting pituitary adenomas: A retrospective analysis of 33 patients

The endoscopic endonasal transsphenoidal approach (EETA) is the primary treatment for growth hormone (GH) adenoma. This study aimed to investigate the outcomes of EETA in 33 patients with GH-secreting pituitary adenoma (PA).Thirty-three patients who underwent EETA in Eighth People's Hospital of Shenzhen between January 2013 and December 2017 were included in the comprehensive analysis. Factors affecting the extent of resection and postoperative remission rates were also reviewed.The total cut rate was 63.6% (21), and the total remission rate was 66.7% (22) in all patients after surgery. The cure rate was 60.6% (20) for 33 patients. The total removal rate and remission rate were significantly different (P = .01, P = .007) for microadenomas, macroadenomas, and giant adenomas. In addition, the total removal rate and remission rate were significantly different (P = .004, P = .007) for patients with noninvasive and invasive GH-secreting PAs. Furthermore, there were significant differences (P = .003, P = .005) in the total removal rate and remission rate of patients with different preoperative GH levels. All patients with hypertension and diabetes mellitus were normalized. Three patients exhibited recurrence after surgery. Several patients suffered from postoperative complications, including transient diabetes insipidus in 3 (9.1%) patients and postoperative transient cerebrospinal fluid leakage in 2 (6.1%) patients.EETA is an effective therapeutic approach for treating patients with GH-secreting PA with high remission and low complication rates. Therefore, EETA should be considered a primary treatment for patients with GH-secreting PA.

Development and Interpretation of Multiple Machine Learning Models for Predicting Postoperative Delayed Remission of Acromegaly Patients During Long-Term Follow-Up

Background: Some patients with acromegaly do not reach the remission standard in the short term after surgery but achieve remission without additional postoperative treatment during long-term follow-up; this phenomenon is defined as postoperative delayed remission (DR). DR may complicate the interpretation of surgical outcomes in patients with acromegaly and interfere with decision-making regarding postoperative adjuvant therapy. Objective: We aimed to develop and validate machine learning (ML) models for predicting DR in acromegaly patients who have not achieved remission within 6 months of surgery. Methods: We enrolled 306 acromegaly patients and randomly divided them into training and test datasets. We used the recursive feature elimination (RFE) algorithm to select features and applied six ML algorithms to construct DR prediction models. The performance of these ML models was validated using receiver operating characteristics analysis. We used permutation importance, SHapley Additive exPlanations (SHAP), and local interpretable model-agnostic explanation (LIME) algorithms to determine the importance of the selected features and interpret the ML models. Results: Fifty-five (17.97%) acromegaly patients met the criteria for DR, and five features (post-1w rGH, post-1w nGH, post-6m rGH, post-6m IGF-1, and post-6m nGH) were significantly associated with DR in both the training and the test datasets. After the RFE feature selection, the XGboost model, which comprised the 15 important features, had the greatest discriminatory ability (area under the curve = 0.8349, sensitivity = 0.8889, Youden's index = 0.6842). The XGboost model showed good discrimination ability and provided significantly better estimates of DR of patients with acromegaly compared with using only the Knosp grade. The results obtained from permutation importance, SHAP, and LIME algorithms showed that post-6m IGF-1 is the most important feature in XGboost algorithm prediction and showed the reliability and the clinical practicability of the XGboost model in DR prediction. Conclusions: ML-based models can serve as an effective non-invasive approach to predicting DR and could aid in determining individual treatment and follow-up strategies for acromegaly patients who have not achieved remission within 6 months of surgery.

Surgical Results and Predictors of Initial and Delayed Remission for Growth Hormone-Secreting Pituitary Adenomas Using the 2010 Consensus Criteria in 162 Patients from a Single Center

BACKGROUND

The factors associated with initial and delayed remission after growth hormone (GH)-secreting pituitary adenoma excision have not been completely elucidated.

METHODS

We recruited 185 consecutive patients who had undergone resection of GH-secreting pituitary adenomas from January 2013 to December 2014 and assessed their tumor characteristics and surgical outcomes. The criteria for initial or delayed remission (using the 2010 consensus criteria) were normalized insulin-like growth factor 1 (IGF-1) levels, GH levels <0.4 μg/L with an oral glucose tolerance test, and/or random GH levels <1.0 μg/L at or after the postoperative 3-month (PO3M) follow-up, without adjuvant therapy.

RESULTS

Remission was achieved in 92 of 162 patients (56.8%) after surgery alone and was associated with a lower Knosp grade of 0-2 and lower postoperative day 1 GH level on multivariate regression analysis. A baseline IGF-1 index (IGF-1 level/upper limit of normal) of <2.835 predicted for initial remission at the PO3M follow-up (positive predictive value, 95.3%; negative predictive value, 36.6%; P < 0.001). The PO3M IGF-1 index was significantly lower in the delayed remission group than in the nonremission group. Furthermore, the former had had fewer invasive tumors (1.23 ± 0.21 vs. 1.77 ± 0.37 [9.52% vs. 76.47%]; P < 0.001). A PO3M IGF-1 index of <1.485 predicted for delayed remission during subsequent follow-up (positive predictive value, 84.6%; negative predictive value, 92.3%; P < 0.001).

CONCLUSIONS

A lower Knosp grade of 0-2 and lower postoperative day 1 GH level were independent predictors of surgical remission. The baseline IGF-1 and PO3M IGF-1 indexes might predict for initial and delayed remission, respectively.