ENDOCRINE TUMOURS: Our experience with the management of patients with non-metastatic adrenocortical carcinoma

Recovery of adrenal function after stopping mitotane in patients with adrenocortical carcinoma

OBJECTIVE

Mitotane is the standard therapy of adrenocortical carcinoma (ACC) due to its relative selectivity of its cytotoxic effects toward adrenocortical cells. Therefore, it virtually always leads to adrenal insufficiency. Frequency and characteristics of hypothalamic-pituitary-adrenal axis recovery after discontinuation are ill-defined.

METHODS

This was a retrospective study of patients with ACC adjuvantly treated with mitotane for ≥12 months who were disease-free at mitotane stop and had a minimum follow-up ≥1 year. Primary endpoint was adrenal recovery. Cox regression analyses were used to identify predictive factors. Moreover, mitotane plasma elimination rate and hormonal changes after mitotane stop were investigated.

RESULTS

Fifty-six patients (36 women) treated with mitotane for a median time of 25 months and an average daily dose of 2.8 g were included. Median time after discontinuation until mitotane levels dropped below 5 and 2 mg/L, and the detection limit was 152 days (interquartile range: 114-202), 280 days (192-370), and 395 days (227-546), respectively. Full adrenal recovery was documented in 32 (57%) patients after a median time of 26 months (95% confidence interval [CI] = 19.6-32.4). In 4 patients (7.1%), adrenal insufficiency persisted >5 years after discontinuation. Mitotane peak ≥ 27 mg/L significantly correlated with longer time to adrenal recovery (hazard ratio [HR] = 0.2, 95% CI = 0.1-0.8, P = .03). Twenty-seven of 38 patients (71%) followed in reference centers achieved adrenal recovery compared with only 5/18 (28%) followed up in non-reference centers (HR = 4.51, 95% CI = 1.71-11.89, P = .002). Other investigated factors were not associated with adrenal function after discontinuation.

CONCLUSIONS

Our study demonstrates that adrenal recovery occurs in most patients after stopping mitotane, particularly when followed up in specialized centers, but not in all. Elimination time of mitotane after treatment discontinuation is very long but individually quite variable.

Radiopharmaceuticals for Treatment of Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) represents a rare tumor entity with limited treatment options and usually rapid tumor progression in case of metastatic disease. As further treatment options are needed and ACC metastases are sensitive to external beam radiation, novel theranostic approaches could complement established therapeutic concepts. Recent developments focus on targeting adrenal cortex-specific enzymes like the theranostic twin [123/131I]IMAZA that shows a good image quality and a promising therapeutic effect in selected patients. But other established molecular targets in nuclear medicine such as the C-X-C motif chemokine receptor 4 (CXCR4) could possibly enhance the therapeutic regimen as well in a subgroup of patients. The aims of this review are to give an overview of innovative radiopharmaceuticals for the treatment of ACC and to present the different molecular targets, as well as to show future perspectives for further developments since a radiopharmaceutical with a broad application range is still warranted.

Albumin/Mitotane Interaction Affects Drug Activity in Adrenocortical Carcinoma Cells: Smoke and Mirrors on Mitotane Effect with Possible Implications for Patients' Management

BACKGROUND

Mitotane is the only drug approved for the treatment of adrenocortical carcinoma (ACC). Although it has been used for many years, its mechanism of action remains elusive. H295R cells are, in ACC, an essential tool to evaluate drug mechanisms, although they often lead to conflicting results.

METHODS

Using different in vitro biomolecular technologies and biochemical/biophysical experiments, we evaluated how the presence of "confounding factors" in culture media and patient sera could reduce the pharmacological effect of mitotane and its metabolites.

RESULTS

We discovered that albumin, the most abundant protein in the blood, was able to bind mitotane. This interaction altered the effect of the drug by blocking its biological activity. This blocking effect was independent of the albumin source or methodology used and altered the assessment of drug sensitivity of the cell lines.

CONCLUSIONS

In conclusion, we have for the first time demonstrated that albumin does not only act as an inert drug carrier when mitotane or its metabolites are present. Indeed, our experiments clearly indicated that both albumin and human serum were able to suppress the pharmacological effect of mitotane in vitro. These experiments could represent a first step towards the individualization of mitotane treatment in this rare tumor.

Adjuvant mitotane versus surveillance in low-grade, localised adrenocortical carcinoma (ADIUVO): an international, multicentre, open-label, randomised, phase 3 trial and observational study

BACKGROUND

Adjuvant treatment with mitotane is commonly used after resection of adrenocortical carcinoma; however, treatment remains controversial, particularly if risk of recurrence is not high. We aimed to assess the efficacy and safety of adjuvant mitotane compared with surveillance alone following complete tumour resection in patients with adrenocortical carcinoma considered to be at low to intermediate risk of recurrence.

METHODS

ADIUVO was a multicentre, open-label, parallel, randomised, phase 3 trial done in 23 centres across seven countries. Patients aged 18 years or older with adrenocortical carcinoma and low to intermediate risk of recurrence (R0, stage I-III, and Ki67 ≤10%) were randomly assigned to adjuvant oral mitotane two or three times daily (the dose was adjusted by the local investigator with the target of reaching and maintaining plasma mitotane concentrations of 14-20 mg/L) for 2 years or surveillance alone. All consecutive patients at 14 study centres fulfilling the eligibility criteria of the ADIUVO trial who refused randomisation and agreed on data collection via the European Network for the Study of Adrenal Tumors adrenocortical carcinoma registry were included prospectively in the ADIUVO Observational study. The primary endpoint was recurrence-free survival, defined as the time from randomisation to the first radiological evidence of recurrence or death from any cause (whichever occurred first), assessed in all randomly assigned patients by intention to treat. Overall survival, defined as time from the date of randomisation to the date of death from any cause, was a secondary endpoint analysed by intention to treat in all randomly assigned patients. Safety was assessed in all patients who adhered to the assigned regimen, which was defined by taking at least one tablet of mitotane in the mitotane group and no mitotane at all in the surveillance group. The ADIUVO trial is registered with ClinicalTrials.gov, NCT00777244, and is now complete.

FINDINGS

Between Oct 23, 2008, and Dec 27, 2018, 45 patients were randomly assigned to mitotane and 46 to surveillance alone. Because the study was discontinued prematurely, 5-year recurrence-free and overall survival are reported instead of recurrence-free and overall survival as defined in the protocol. 5-year recurrence-free survival was 79% (95% CI 67-94) in the mitotane group and 75% (63-90) in the surveillance group (hazard ratio 0·74 [95% CI 0·30-1·85]). Two people in the mitotane group and five people in the surveillance group died, and 5-year overall survival was not significantly different (95% [95% CI 89-100] in the mitotane group and 86% [74-100] in the surveillance group). All 42 patients who received mitotane had adverse events, and eight (19%) discontinued treatment. There were no grade 4 adverse events or treatment-related deaths.

INTERPRETATION

Adjuvant mitotane might not be indicated in patients with low-grade, localised adrenocortical carcinoma considering the relatively good prognosis of these patients, and no significant improvement in recurrence-free survival and treatment-associated toxicity in the mitotane group. However, the study was discontinued prematurely due to slow recruitment and cannot rule out an efficacy of treatment.

FUNDING

AIFA, ENSAT Cancer Health F2-2010-259735 programme, Deutsche Forschungsgemeinschaft, Cancer Research UK, and the French Ministry of Health.

A Revised Version of the TNM Classification Leads to Optimized Predictive Performance in Patients with Adrenocortical Carcinoma

The prognostic stratification of the current AJCC/UICC TNM classification for adrenocortical carcinoma (ACC) has been validated in only a few studies. In this study, it was hypothesized that redefining the T category cut-off would result in a significant improvement in estimated stage-related survival. In 935 patients with ACC from the SEER database, optimal cut-off values based on tumor size were first determined to redefine T1 and T2 categories. Cox proportional hazards regression analysis and receiver operating characteristics (ROC) were then used to determine the prognostic value of the revised version. A new cut-off value of 9.5 cm tumor size was established to differentiate between T1 and T2 tumors, leading to a revised TNM classification. As a result, a more homogeneous distribution of patients with ACC across all stages was observed. Notably, the predictive value of the newly proposed TNM classification in the ROC analysis exceeded that of the 7th and 8th editions of the AJCC/UICC classification system. Finally, the prognostic superiority of the revised TNM classification was confirmed in a multivariate Cox proportional hazards regression model. In conclusion, the present study demonstrates that updating the current staging system with revised T1 and T2 categories significantly improves the prediction of cancer-specific survival (CSS) in patients with ACC.

Pregnancy in patients with adrenocortical carcinoma: a case-based discussion

Although adrenocortical carcinoma (ACC) during pregnancy is rare, a retrospective review of a case series at our hospital revealed that almost one third of our patients were women in childbearing age. Given that the age of maternity is increasing, dealing with a tumor diagnosis during pregnancy and the need for fertility planning in cancer survivors is likely to become more frequent.We thus carried out a case-based discussion regarding: i) diagnosing and treating an ACC during pregnancy; ii) patients conceiving while on mitotane; iii) ACC survivors with a maternal desire.In each of these cases, it is important to provide patients with sufficient information, to offer medical advice and psychological support, to personalize treatments in accordance with the wishes of the patient and her relatives, and to collaborate with other specialists since a multidisciplinary expert team is required to manage each case individually.

Efficacy and safety of radiation therapy in advanced adrenocortical carcinoma

BACKGROUND

International guidelines emphasise the role of radiotherapy (RT) for the management of advanced adrenocortical carcinoma (ACC). However, the evidence for this recommendation is very low.

METHODS

We retrospectively analysed all patients who received RT for advanced ACC in five European centres since 2000.

PRIMARY ENDPOINT

time to progression of the treated lesion (tTTP). Secondary endpoints: best objective response, progression-free survival (PFS), overall survival (OS), adverse events, and the establishment of predictive factors by Cox analyses.

RESULTS

In total, 132 tumoural lesions of 80 patients were treated with conventional RT (cRT) of 50-60 Gy (n = 20) or 20-49 Gy (n = 69), stereotactic body RT of 35-50 Gy (SBRT) (n = 36), or brachytherapy of 12-25 Gy (BT) (n = 7). Best objective lesional response was complete (n = 6), partial (n = 52), stable disease (n = 60), progressive disease (n = 14). Median tTTP was 7.6 months (1.0-148.6). In comparison to cRT20-49Gy, tTTP was significantly longer for cRT50-60Gy (multivariate adjusted HR 0.10; 95% CI 0.03-0.33; p < 0.001) and SBRT (HR 0.31; 95% CI 0.12-0.80; p = 0.016), but not for BT (HR 0.66; 95% CI 0.22-1.99; p = 0.46). Toxicity was generally mild and moderate with three grade 3 events. No convincing predictive factors could be established.

CONCLUSIONS

This largest published study on RT in advanced ACC provides clear evidence that RT is effective in ACC.

The management of postoperative disease recurrence in patients with adrenocortical carcinoma: a retrospective study in 106 patients

OBJECTIVE

The management of adrenocortical carcinoma (ACC) recurrences remains controversial, and we present herein our experience with postoperative ACC recurrences.

DESIGN AND METHODS

Retrospective analysis in a single reference center of 106 patients with ACC recurrence.

RESULTS

The median follow-up was 45 months, the median recurrence-free survival (RFS) 12 months (IQR 6-23), and the median overall survival (OS) 45 months (IQR 29-75). ACC recurrences occurred as a unique lesion (group A) in 35.8%, multiple lesions in a single organ (group B) in 20.8%, and affecting multiple organs (group C) in 43.4% of patients. Baseline characteristics of patients stratified by the type of recurrence did not differ between them, except RFS, which was significantly longer in group A. Locoregional treatments were used in 100% of patients of group A, 68.2% in group B, and 26.1% in group C. After treatment of recurrence, 60.4% of patients became free of disease attaining a second RFS of 15 months (IQR 6-64). Margin status RX and R1, percent increase in Ki67, and recurrence in multiple organs were associated with an increased risk of mortality, while adjuvant mitotane treatment and longer time to first recurrence were associated with reduced risk. Recurrence in multiple organs and systemic treatment of recurrence had a negative impact on survival from the treatment of recurrence.

CONCLUSIONS

This study shows that patients with ACC have a better prognosis when the disease recurs as a single lesion and supports the use of locoregional treatments to treat disease recurrence.

High expression of GMNN predicts malignant progression and poor prognosis in ACC

BACKGROUND

Adrenocortical carcinoma (ACC) is a rare endocrine neoplasm, which is characterized by poor prognosis and high recurrence rate. Novel and reliable prognostic and metastatic biomarkers are lacking for ACC patients. This study aims at screening potential prognostic biomarkers and therapeutic targets of ACC through bioinformatic methods and immunohistochemical (IHC) analysis.

METHODS

In the present study, by using the Gene Expression Omnibus (GEO) database we identified differentially expressed genes (DEGs) in ACC and validated these DEGs in The Cancer Genome Atlas (TCGA) ACC cohort. A DEGs-based signature was additionally constructed and we assessed its prognosis and prescient worth for ACC by survival analysis and nomogram. Immunohistochemistry (IHC) was used to verify the relationship between hub gene-GMNN expressions and clinicopathologic outcomes in ACC patients.

RESULTS

A total of 24 DEGs correlated with the prognosis of ACC were screened from the TCGA and GEO databases. Five DEGs were subsequently selected in a signature which was closely related to the survival rates of ACC patients and GMNN was identified as the core gene in this signature. Univariate and multivariate Cox regression showed that the GMNN was an independent prognostic factor for ACC patients (P < 0.05). Meanwhile, GMNN was closely related to the OS and PFI of ACC patients treated with mitotane (P < 0.001). IHC confirmed that GMNN protein was overexpressed in ACC tissues compared with normal adrenal tissues and significantly correlated with stage (P = 0.011), metastasis (P = 0.028) and Ki-67 index (P = 0.014).

CONCLUSIONS

GMNN is a novel tumor marker for predicting the malignant progression, metastasis and prognosis of ACC, and may be a potential therapeutic target for ACC.

Construction and validation of a prognostic model for predicting overall survival of primary adrenal malignant tumor patients: A population-based study with 1,080 patients

Objective

Primary adrenal malignant tumor is rare. The factors affecting the prognosis remain poorly defined. This study targeted to construct and corroborate a model for predicting the overall survival of adrenal malignant tumor patients.

Methods

We investigated the SEER database for patients with primary adrenal malignant tumor. 1,080 patients were divided into a construction cohort (n = 756) and a validation cohort (n = 324), randomly. The prognostic factors for overall survival were evaluated using univariate and multivariate Cox analyses. The nomogram was constructed and then validated with C-index, calibration curve, time-dependent ROC curve, and decision curve analysis in both cohorts. Then we divided the patients into 3 different risk groups according to the total points of the nomogram and analyzed their survival status by Kaplan-Meier curve with log-rank test.

Results

The baseline characteristics of these two cohorts were not statistically different (P > 0.05). Using univariate and multivariate Cox analyses, 5 variables, including age, tumor size, histological type, tumor stage, and surgery of primary site, were distinguished as prognostic factors (P < 0.05). Based on these variables, we constructed a nomogram to predict the 3- year, 5- year, and 10-year overall survival. The C-indexes were 0.780 (0.760–0.800) in the construction cohort and 0.780 (0.751–0.809) in the validation cohort. In both cohorts, the AUC reached a fairly high level at all time points. The internal and external calibration curves and ROC analysis showed outstanding accuracy and discrimination. The decision curves indicated excellent clinical usefulness. The best cut-off values for the total points of the nomogram were 165.4 and 243.1, and the prognosis was significantly different for the three different risk groups (P < 0.001).

Conclusion

We successfully constructed a model to predict the overall survival of primary adrenal malignant tumor patients. This model was validated to perform brilliantly internally and externally, which can assist us in individualized clinical management.