Effects of mitotane on the hypothalamic-pituitary-adrenal axis in patients with adrenocortical carcinoma

OBJECTIVE

Mitotane, a drug used to treat adrenocortical cancer (ACC), inhibits multiple enzymatic steps of adrenocortical steroid biosynthesis, potentially causing adrenal insufficiency. Recent studies in vitro have also documented a direct inhibitory effect of mitotane at the pituitary level. The present study was aimed to assess the hypothalamic-pituitary-adrenal axis in patients with ACC receiving mitotane.

DESIGN AND METHODS

We prospectively enrolled 16 patients on adjuvant treatment with mitotane after radical surgical resection of ACC, who underwent standard hormone evaluation and h-CRH stimulation. A group of 10 patients with primary adrenal insufficiency (PAI) served as controls for the CRH test.

RESULTS

We demonstrated a close correlation between cortisol-binding globulin (CBG) and plasma mitotane levels, and a non-significant trend between mitotane dose and either serum or salivary cortisol in ACC patients. We did not find any correlation between the dose of cortisone acetate and either ACTH or cortisol levels. ACTH levels were significantly higher in patients with PAI than that in patients with ACC, both in baseline conditions (88.99 (11.04-275.00) vs 24.53 (6.16-121.88) pmol/L, P = 0.031) and following CRH (158.40 (34.32-275.00) vs 67.43 (8.8-179.52) pmol/L P = 0.016).

CONCLUSIONS

The observation of lower ACTH levels in patients with ACC than that in patients with PAI, both in basal conditions and after CRH stimulation, suggests that mitotane may play an inhibitory effect on ACTH secretion at the pituitary levels. In conclusion, the present study shows that mitotane affects the HPA axis at multiple levels and no single biomarker may be used for the assessment of adrenal insufficiency.

Topoisomerase 2α and thymidylate synthase expression in adrenocortical cancer

Topoisomerase II alpha (TOP2A) and thymidylate synthase (TS) are known prognostic parameters in several tumors and also predictors of efficacy of anthracyclines, topoisomerase inhibitors and fluoropirimidines, respectively. Expression of TOP2A and TS mRNA was assessed in 98 patients with adrenocortical carcinoma (ACC) and protein expression was assessed by immunohistochemistry in a subset of 39 tumors. Ninety-two patients were radically resected for stage II-III disease and 38 of them received adjuvant mitotane. Twenty-six patients with metastatic disease received the EDP-M (etoposide, doxorubicin, Adriamycin, cisplatin plus mitotane). TOP2A and TS expression in ACC tissue was directly correlated with the clinical data. Both markers were not associated with either disease free survival (DFS) or overall survival (OS) in multivariate analyses and failed to be associated to mitotane efficacy. Disease response or stabilization to EDP-M treatment was observed in 12/17 (71%) and 1/9 (11%) patients with high and low TOP2A expressing tumors (P = 0.0039) and 9/13 (69%) and 4/13 (31%) patients with high and low TS expressing ACC, respectively (P = 0.049). High TOP2A expression was significantly associated with longer time to progression (TTP) after EDP-M. TOP2A and TS proteins assessed by immunohistochemistry significantly correlated with mRNA expression. Immunohistochemical TOP2A expression was associated with a non-significant better response and longer TTP after EDP-M. TOP2A and TS were neither prognostic nor predictive of mitotane efficacy in ACC patients. The predictive role of TOP2A expression of EDP-M activity suggests a significant contribution of Adriamycin and etoposide for the efficacy of the EDP scheme.

Long-Term Outcomes of Adjuvant Mitotane Therapy in Patients With Radically Resected Adrenocortical Carcinoma

CONTEXT

In 2007, a retrospective case-control study provided evidence that adjuvant mitotane prolongs recurrence-free survival (RFS) in patients with radically resected adrenocortical carcinoma (ACC).

OBJECTIVE AND DESIGN

We aimed to confirm the prognostic role of adjuvant mitotane in the same series after 9 additional years of follow-up.

SETTING, PATIENTS, AND INTERVENTIONS

One hundred sixty-two ACC patients who did not recur or die after a landmark period of 3 months were considered. Forty-seven patients were enrolled in four Italian centers where adjuvant mitotane was routinely recommended (mitotane group), 45 patients in four Italian centers where no adjuvant strategy was undertaken (control group 1), and 70 German patients left untreated after surgery (control group 2).

MAIN OUTCOME MEASURES

The primary aim was RFS, the secondary was overall survival.

RESULTS

An increased risk of recurrence was found in both control cohorts [group 1: hazard ratio (HR) = 2.98; 95% confidence interval (CI), 1.75 to 5.09; P < 0.0001; group 2: HR = 2.61; 95% CI, 1.56 to 4.36; P < 0.0001] compared with the mitotane group. The risk of death was higher in control group 1 (HR = 2.03; 95% CI, 1.17 to 3.51; P = 0.011) but not in control group 2 (HR = 1.60; 95% CI, 0.94 to 2.74; P = 0.083), which had better prognostic factors and more aggressive treatment of recurrences than control group 1. The benefit of adjuvant mitotane on RFS was observed regardless of the hormone secretory status.

CONCLUSIONS

Adjuvant mitotane is associated with prolonged RFS, without any apparent influence by the tumor secretory status. The retrospective nature of the study is a major limitation.

Validation of the prognostic role of the "Helsinki Score" in 225 cases of adrenocortical carcinoma

Adrenocortical carcinoma patient prognosis is extremely variable and poorly predictable. The newly introduced Helsinki Score is the first so far proposed diagnostic and prognostic system based on the combined evaluation of morphological (mitoses and necrosis) and immunohistochemical (Ki-67) parameters. The aim of the study was to validate the prognostic role of the Helsinki Score for adrenocortical carcinoma characterization. Thus, 225 adrenocortical carcinomas were reclassified using the Weiss Score and the Helsinki Score (3× mitotic count + 5 × necrosis + Ki-67 index). At univariate analysis, statistically significant prognostic values were observed at the log-rank test for mitotic count (cutoff values: <6 and ≥55; P<.0001), Ki-67 (cutoff values: <20 and ≥50; P<.0001), Weiss Score (cutoff values: <5 and ≥8; P<.0001), Helsinki Score (cutoff values: <13 and ≥19; P<.0001), histological variant (conventional versus oncocytic; P=.009), necrosis (P=.001), and stage (P=.005). Cox multivariate analysis using a backward stepwise selection method retained only Helsinki Score and Weiss Score as predictors of poor prognosis (P<.0001 and P=.0005, respectively). Helsinki Score (with a threshold of 28.5 points; area under the curve [AUC]=0.729, 95% confidence interval=0.66-0.79) and Ki-67 (with a threshold of 20.5%; AUC=0.727, 95% confidence interval=0.66-0.79) showed the best and equivalent AUCs predicting disease-related deaths determined using receiver operating characteristic statistics. In conclusion, the Helsinki Score is a valuable system to predict prognosis in adrenocortical carcinoma, outperforming the currently established prognostic parameters.

Prognostic factors in stage III-IV adrenocortical carcinomas (ACC): an European Network for the Study of Adrenal Tumor (ENSAT) study

BACKGROUND

The clinical course of advanced adrenocortical carcinoma (ACC) is heterogeneous. Our study aimed primarily to refine and make headway in the prognostic stratification of advanced ACC.

PATIENTS AND METHODS

Patients with advanced ENSAT ACC (stage III or stage IV) at diagnosis registered between 2000 and 2009 in the ENSAT database were enrolled. The primary end point was overall survival (OS). Parameters of potential prognostic relevance were selected. Univariate and multivariate analyses were carried out: model 1 'before surgery'; model 2 'post-surgery'.

RESULTS

Four hundred and forty-four patients with advanced ENSAT ACC (stage III: 210; stage IV: 234) were analyzed. After a median follow-up of 55.2 months, the median OS was 24 months. A modified ENSAT (mENSAT) classification was validated: stage III (invasion of surrounding tissues/organs or the vena renalis/cava) and stage IVa, IVb, IVc (2, 3 or >3 metastatic organs, including N, respectively). Two- or 5-year OS was 73%, 46%, 26% and 15% or 50%, 15%, 14% and 2% for stages III, IVa, IVb and IVc, respectively. In the multivariate analysis, mENSAT stages (stages IVa, IVb, or IVc, respectively) were significantly correlated with OS (P < 0.0001), as well as additional parameters: age ≥ 50 years (P < 0.0001), tumor- or hormone-related symptoms (P = 0.01 and 0.03, respectively) in model 1 but also the R status (P = 0.001) and Grade (Weiss >6 and/or Ki67 ≥ 20%, P = 0.06) in model 2.

CONCLUSION

The mENSAT classification and GRAS parameters (Grade, R status, Age and Symptoms) were found to best stratify the prognosis of patients with advanced ACC.

Does nephrectomy during radical adrenalectomy for stage II adrenocortical cancer affect patient outcome?

PURPOSE

To evaluate if including nephrectomy in the standard surgical approach to stage II adrenocortical cancer (i.e., adrenalectomy) might modify oncologic outcome of patients.

METHODS

We performed a retrospective analysis involving 41 patients with stage II adrenocortical cancer (ACC) who had undergone radical surgery. Patients were divided into two groups according to the surgical procedure: group A = radical adrenalectomy alone, group AN = radical adrenalectomy + radical nephrectomy. Oncologic effectiveness of the procedures was tested comparing the recurrence-free and overall survival of patients of A vs AN groups.

RESULTS

The group A consisted of 25 patients and group AN of 16 patients. No differences were noted between the two groups in terms of demographic data and ACC characteristics. During follow-up, 15/25 (60 %) patients of group A vs 14/16 (87.5 %) patients of group AN experienced a recurrence, after a median of 36 months in group A and 10 months in group AN (p = 0.06); a significant impairment of renal function was recorded in patients of AN group with respect to those of group A. Finally, 13/25 (52 %) patients of group A and 10/16 (62.5 %) patients of group AN died due to ACC-related causes. No differences in survival times were noted (p = 0.3).

CONCLUSION

Our study suggests that adjunctive nephrectomy does not modify the oncologic results of adrenalectomy in the treatment of stage II ACC in terms of recurrence-free and overall survival. Thus, when there are no signs of ACC local invasion, surgeon should make every effort to preserve the kidney.

18F-FDG PET/CT in the post-operative monitoring of patients with adrenocortical carcinoma

CONTEXT

The role of (18)F-labeled 2-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) in the post-operative monitoring of patients with adrenocortical carcinoma (ACC) is still unclear.

OBJECTIVE

To assess the accuracy of FDG PET/CT to diagnose ACC recurrence in a real world setting.

DESIGN AND METHODS

Retrospective evaluation of data of 57 patients with presumed ACC recurrence at CT scan who underwent FDG PET/CT within a median time of 20 days. We compared the results of either FDG PET/CT or CT with a gold standard confirmation of recurrence (positive histopathology report of removed/biopsied lesions or radiological progression of target lesions at follow-up) to assess their diagnostic performance at different body sites to correctly categorize target lesions. We also assessed whether FDG PET/CT findings may be useful to inform the management strategy.

RESULTS

In 48 patients with confirmed ACC recurrence, we found that FDG PET/CT had lower sensitivity than CT in diagnosing liver and lung recurrences of ACC. FDG PET/CT had higher specificity than CT in categorizing liver lesions. FDG PET/CT had a greater positive likelihood ratio than CT to identify liver and abdominal ACC recurrences. The management strategy was changed based on FDG PET/CT findings in 12 patients (21.1%).

CONCLUSIONS

The greater sensitivity of CT may be partly expected due the specific inclusion criteria of the study; however, the greater specificity of FDG PET/CT was particularly useful in ruling out suspected ACC recurrences found by CT. Thus, use of FDG PET/CT as a second-line test in the post-operative surveillance of ACC patients following CT finding of a potential recurrence may have a significant impact on patient management.

Evaluation of Midnight Salivary Cortisol as a Predictor Factor for Common Carotid Arteries Intima Media Thickness in Patients with Clinically Inapparent Adrenal Adenomas

Purpose. The aim of the present study was to investigate the atherosclerotic vascular damage in a consecutive series of patients with AI and to correlate it with MSC. Methods. We studied 32 patients with AI matched with control subjects for age, sex, and cardiovascular risk factors. Either patients or control subjects underwent MSC measurement as outpatients and carotid arteries ultrasound (US) imaging studies. Results. The patients with AI had higher mean carotid artery IMT values and higher MSC levels than control subjects. In a multivariate analysis performed in AI age was the best predictor for IMT. We have stratified patients and control subjects by age (<60 yrs and ≥60 yrs). The patients showed significantly higher MSC levels than controls in both groups, whereas significantly higher IMT values were observed only in older subjects. Conclusions. Patients with AI have signs of accelerated atherosclerosis. Patients older than 60 years seem more susceptible to the possible detrimental effect of subclinical hypercortisolism on cardiovascular system. The MSC levels are not a strong predictor of the accelerated atherosclerosis, but they seem to indicate the subtle but not autonomous cortisol excess that may potentially raise the cardiovascular risk.

Practical treatment using mitotane for adrenocortical carcinoma

PURPOSE OF REVIEW

Description of novel findings about the mechanism of action of mitotane and its activity as an adjunctive postoperative measure, or for treatment of advanced adrenocortical carcinoma.

RECENT FINDINGS

Several in-vitro studies have shown that mitotane suppresses gene transcription of different enzymatic steps of the steroidogenetic pathway. Moreover, mitotane induces CYP3A4 expression, thus accelerating the metabolic clearance of a variety of drugs including steroids. Retrospective studies provided evidence that adjunctive mitotane can prolong recurrence-free survival of treated patients. The concept of a therapeutic window of mitotane plasma concentrations was confirmed also for adjunctive treatment, but the relationship between mitotane concentration and given dose is loose. Genetic variability of the P450-dependent enzymes metabolizing mitotane may explain individual differences.

SUMMARY

Mitotane concentration of 14-20  mg/l should be reached and maintained during treatment also in an adjunctive setting. In advanced adrenocortical carcinoma, a high-dose starting regimen should be employed when mitotane is used as monotherapy. The combination of mitotane with other drugs should consider the possibility of pharmacologic interactions due to mitotane-induced activation of drug metabolism. This concept applies also to steroid replacement in mitotane-treated patients, who need higher doses to adjust for increased steroid metabolism.

Management of adrenal cancer: a 2013 update

Adrenocortical carcinoma (ACC) is a devastating tumor for either patients or their families because of short life expectancy and severe impact on quality of life. Due to the rarity of ACC, with a reported annual incidence of 0.5-2 cases per million population, progress in the development of treatment options beyond surgery has been limited. Up to now, no personalized approach of ACC therapy has emerged, apart from plasma level-guided mitotane therapy, and no simple targetable molecular event has been identified from preclinical studies. Complete surgical removal of ACC is the only potentially curative approach and has the most important impact on patient’s prognosis. Despite the limits of the available evidence, adjuvant mitotane therapy is currently recommended in many expert centers whenever the patients present an elevated risk of recurrence. The management of patients with recurrent and metastatic disease is challenging and the prognosis is often poor. Mitotane monotherapy is indicated in the management of patients with a low tumor burden and/or more indolent disease while patients whose disease show an aggressive behavior need cytotoxic chemotherapy. The treatment of patients with advanced ACC may include loco-regional approaches such as surgery and radiofrequency ablation in addition to systemic therapies. The present review provides an updated overview of the management of ACC patients following surgery and of the management of ACC patients with advanced disease.

Growth hormone values after an oral glucose load do not add clinically useful information in patients with acromegaly on long-term somatostatin receptor ligand treatment

The optimal method of assessing GH status in acromegalic patients receiving medical therapy with somatostatin analogs (SSA) has been matter of debate. The aim of the study has been to investigate whether OGTT may add information in patients with discordant random GH (GHr) and IGF values. Moreover, we evaluated the association of GH nadir with the prevalence of co-morbidities observed in acromegalic patients on SSA therapy. We evaluated 130 patients with proven diagnosis of acromegaly on SSA. The patients were subdivided in three groups: patients with controlled disease (both safe random GH and normal IGF-I, group A, 20.0 %), patients with uncontrolled disease (both high random GH and IGF-I, group B, 34.6 %), and patients with discordant random GH and IGF-I values (group C, 35.4 %). A high concordance rate for GH nadir with random GH and IGF-I was observed in group B, while a significant reduced concordance rate has been observed in group A (100 % sensitivity, 64.5 % specificity). By contrast, in group C, we observed concordant results between GH nadir and IGF-I only in 14/59 patients. In group A, the prevalence of diabetes was lower than in group B or C. Safe random GH was the only single criteria associated with a lower prevalence of diabetes. Discrepant IGF-I and either GH nadir or random GH values are frequently observed in acromegalic patients treated with SSA. Concordant IGF-I and random GH may influence the prevalence of metabolic complications. GH nadir measurement may help to interpret discrepancies between random GH and IGF-I data only in few cases.

Mitotane levels predict the outcome of patients with adrenocortical carcinoma treated adjuvantly following radical resection

CONTEXT

Mitotane plasma concentrations ≥ 14 mg/l have been shown to predict tumor response and better survival in patients with advanced adrenocortical carcinoma (ACC). A correlation between mitotane concentrations and patient outcome has not been demonstrated in an adjuvant setting.

OBJECTIVE

To compare recurrence-free survival (RFS) in patients who reached and maintained mitotane concentrations ≥ 1 4 mg/l vs patients who did not.

DESIGN AND SETTING

Retrospective analysis at six referral European centers.

PATIENTS

Patients with ACC who were radically resected between 1995 and 2009 and were treated adjuvantly with mitotane targeting concentrations of 14-20 mg/l.

MAIN OUTCOME MEASURES

RFS (primary) and overall survival (secondary).

RESULTS

Of the 122 patients included, 63 patients (52%) reached and maintained during a median follow-up of 36 months the target mitotane concentrations (group 1) and 59 patients (48%) did not (group 2). ACC recurrence was observed in 22 patients of group 1 (35%) and 36 patients in group 2 (61%). In multivariable analysis, the maintenance of target mitotane concentrations was associated with a significantly prolonged RFS (hazard ratio (HR) of recurrence: 0.418, 0.22-0.79; P=0.007), while the risk of death was not significantly altered (HR: 0.59, 0.26-1.34; P=0.20). Grades 3-4 toxicity was observed in 11 patients (9%) and was managed with temporary mitotane discontinuation. None of the patients discontinued mitotane definitively for toxicity.

CONCLUSIONS

Mitotane concentrations ≥ 14 mg/l predict response to adjuvant treatment being associated with a prolonged RFS. A monitored adjuvant mitotane treatment may benefit patients after radical removal of ACC.

Management of adjuvant mitotane therapy following resection of adrenal cancer

Whenever adrenal cancer (ACC) is completely removed we should face the dilemma to treat by means of adjuvant therapy or not. In our opinion, adjuvant mitotane is the preferable approach in most cases because the majority of patients following radical removal of an ACC have an elevated risk of recurrence. A better understanding of factors that influence prognosis and response to treatment will help in stratifying patients according to their probability of benefiting from adjuvant mitotane, with the aim of sparing unnecessary toxicity to patients who are likely unresponsive. However, until significant advancements take place, we have to deal with uncertainty using our best clinical judgement and personal experience in the clinical decision process. In the present paper, we present the current evidence on adjuvant mitotane treatment and describe the management strategies of patients with ACC after complete surgical resection. We acknowledge the limit that most recommendations are based on personal experience rather than solid evidence.

Mitotane treatment for adrenocortical carcinoma: an overview

Adrenocortical carcinoma (ACC) is a rare aggressive endocrine neoplasm characterized by a 5-year survival of less than 50%. Due to the widespread use of imaging techniques in clinics, ACC is increasingly recognized as an incidentally discovered tumor. Mostly characterized by poor prognosis, ACC is often diagnosed at an advanced stage of disease. Early diagnosis is uncommon; when diagnosed, ACCs are usually large and have invaded adjacent organs, even if metastatic spread to distant sites can be absent. Complete surgical resection is the only potentially curative treatment for patients with localized disease; however, due to a recurrence rate of 50-70% after apparent radical surgery, there is a strong rationale for a concomitant systemic treatment. Adrenolytic therapy with mitotane (o,p›-DDD), administered alone or in combination with others antineoplastic agents, is the primary treatment for patients with advanced ACC and is increasingly used also in an adjuvant setting, even if controversy exists on this issue due to the limitations of the available literature. Despite being in use for many years, the rarity of ACC precluded the organization of randomized trials; thus, many areas of uncertainty and controversy remain regarding the role of this old drug in the clinical management of patients with ACC. The purpose of this paper is to review the current evidence on mitotane treatment in patients with advanced disease and in ACC patients after complete surgical resection as adjuvant treatment.

Prospective evaluation of mitotane toxicity in adrenocortical cancer patients treated adjuvantly

Toxicity of adjuvant mitotane treatment is poorly known; thus, our aim was to assess prospectively the unwanted effects of adjuvant mitotane treatment and correlate the findings with mitotane concentrations. Seventeen consecutive patients who were treated with mitotane after radical resection of adrenocortical cancer (ACC) from 1999 to 2005 underwent physical examination, routine laboratory evaluation, monitoring of mitotane concentrations, and a hormonal work-up at baseline and every 3 months till ACC relapse or study end (December 2007). Mitotane toxicity was graded using NCI CTCAE criteria. All biochemical measurements were performed at our center and plasma mitotane was measured by an in-house HPLC assay. All the patients reached mitotane concentrations >14 mg/l and none of them discontinued definitively mitotane for toxicity; 14 patients maintained consistently elevated mitotane concentrations despite tapering of the drug. Side effects occurred in all patients but were manageable with palliative treatment and adjustment of hormone replacement therapy. Mitotane affected adrenal steroidogenesis with a more remarkable inhibition of cortisol and DHEAS than aldosterone. Mitotane induced either perturbation of thyroid function mimicking central hypothyroidism or, in male patients, inhibition of testosterone secretion. The discrepancy between salivary and serum cortisol, as well as between total and free testosterone, is due to the mitotane-induced increase in hormone-binding proteins which complicates interpretation of hormone measurements. A low-dose monitored regimen of mitotane is tolerable and able to maintain elevated drug concentrations in the long term. Mitotane exerts a complex effect on the endocrine system that may require multiple hormone replacement therapy.

The combined low-dose dexamethasone suppression corticotropin-releasing hormone test as a tool to rule out Cushing's syndrome

OBJECTIVE

It remains to be evaluated whether the combined low-dose dexamethasone suppression corticotropin-releasing hormone test (LDDST-CRH test) may add to the diagnostic approach of patients suspected to have Cushing's syndrome (CS). The aim of the present study was to evaluate whether the LDDST-CRH test may have a place in the diagnostic strategy of CS.

DESIGN

Prospective evaluation of a consecutive series of patients with suspected CS from 2004 to 2006.

METHODS

All the subjects underwent the same screening protocol including 1 mg dexamethasone suppression test, 24-h urinary free cortisol (UFC), and midnight serum cortisol, followed by the LDDST-CRH test whose results were not used to establish a definitive diagnosis. Plasma dexamethasone concentration was measured 2 h after the last dose of dexamethasone. Patients qualified for CS when at least two screening tests were positive.

RESULTS

Sixteen patients had CS while in the remaining 15 subjects CS was excluded. Even if not statistically significant, the sensitivity and the negative predictive value of the cortisol 15 min after CRH were better than the other tests; on the other hand, the test specificity was lower. All of the patients classified as indeterminate were correctly diagnosed by the LDDST-CRH test. Nevertheless, the repeated assessment of the screening tests and the active follow-up gave the same correct results. In all of the patients misclassified by the LDDST-CRH test, the plasma dexamethasone concentrations were in the normal range.

CONCLUSIONS

Based on our findings, we suggest that the LDDST-CRH test may still find a place as a rule-out procedure in patients who present with indeterminate results after screening and may be unavailable to repeat testing during follow-up.