A total of 3,780 patients were entered in the EUROCRINE® registry from 01/2015 to 12/2020, and 2,660 patients from 11 different countries and 69 different hospitals met the criteria to be included in the study. Reasons for exclusion are summarized in Fig. 1. Of those, 1,696 underwent an LTA (63.8%) and 964 a PRLA (36.2%). Patient, hospital, preoperative, and tumour characteristics are summarized in Table 1. In the overall cohort, median age was 54 (44–64) years, female-to-male was ratio 1.4, and median BMI was 27.2 (23.8–30.9) kg/m2 with 777 patients (30%) being obese. PRLA was more frequently performed in experienced centres, in female, younger, heavier patients, and in right-sided tumours. Most tumours (N = 1671, 62.8%) were hormonally active, with aldosterone (N = 767, 28.8%) being the most frequent hormone. More phaeochromocytomas and less cortisol-secreting tumours were operated via LTA (p < 0.001). Median tumour size was 33 (20–50) mm. In 844 patients (31.8%), a malignancy was suspected on imaging and/or cytology prior to surgery, whereas 206 patients (7.7%) underwent adrenal surgery for metastasis. Tumour size was the main indication for surgery in 283 patients (10.6%), with a median tumour size of 50 (40–63) mm in this subgroup. A conversion to open surgery was performed in 44 patients (1.7%), mainly because of bleeding (N = 20), difficult access (N = 12), unclear anatomy (N = 11), or adhesions (N = 5).
Surgical outcome, morbidity, and final histopathology are summarized in Table 2. In total, 96 patients (3.6%) developed a complication Clavien-Dindo grade 2 or higher. No statistical difference was found between both study groups. Most common complications were all-cause infections (N = 45, 1.7%), respiratory complications (N = 18, 0.7%), and haemorrhage requiring blood transfusion (N = 17, 0.6%).
Length of hospital stay was longer in the LTA group, with more patients staying over 2 days (N = 1,094, 65.0% vs N = 434, 45.5%, p < 0.001). Thirteen patients (0.5%) were reoperated, and 40 patients (1.5%) had to be readmitted after discharge. The 30-day all-cause mortality was low (N = 4, 0.2%). Final histopathology showed 60 adrenocortical cancers (2.3%), 1,382 adrenocortical adenomas (52.0%), and 546 phaeochromocytomas (20.5%).
Factors associated with morbidity (Clavien-Dindo grade 2 or higher) after adrenalectomy in the univariate logistic regression analysis included age, male sex, conversion to open surgery, and center inexperience. After multivariable logistic regression analysis, age (OR 1.03, 95%CI 1.01–1.04, p = 0.002), male sex (OR 1.52, 95%CI 1.01–2.29, p = 0.047), and conversion to open surgery (OR 5.73, 95%CI 2.57–12.79, p < 0.001) were the only factors associated with morbidity (Clavien-Dindo grade 2 or higher) (Table 3).
Sensitivity analyses comparing LTA and PRLA showed a longer length of hospital stay after LTA in patients with BMI ≥ 30 kg/m² (63.7% vs 50.2%, p < 0.001), with tumour size ≥ 50 mm (71.7% vs 47.7%, p < 0.001), and with pheochromocytoma (77.9% vs 60.3%, p < 0.001). No differences in conversion rate were found in these subgroups (data not shown).
Sixty patients (39 LTA vs 21 PRLA) underwent surgery for adrenocortical cancer. PRLA was only performed in experienced centres (100%) in younger patients (44 vs 58 years old, p < 0.001) without differences in length of hospital stay (p = 0.465) or morbidity (Clavien-Dindo grade 2 or higher) (p = 0.537). Remarkably, in 185 patients (121 LTA and 64 PRLA) undergoing surgery for malignant adrenal tumours (other than adrenocortical cancer and pheochromocytomas), length of hospital stay was not statistically different (p = 0.307), but morbidity (Clavien-Dindo grade 2 or higher) significantly higher after PRLA (15.6% vs 5.0%, p = 0.014).
Subgroup analysis according to side of the tumour showed that patients with left-sided tumours were slightly younger (54 vs 55 years old, p = 0.047), heavier (BMI ≥ 30 kg/m² 33.7% vs 28.0%, p = 0.030), and operated more in experienced centres (87.8% vs 83.3%, p = 0.008) when operated via PRLA. Length of hospital stay was shorter (> 2 days 41.6% vs 65.7%, p < 0.001) and morbidity (Clavien-Dindo grade 2 or higher) lower in the PRLA group (2.1% vs 4.4%, p = 0.035) (Supplementary Table S1). Patients with right-sided tumours were slightly younger (54 vs 55 years old, p = 0.010) and heavier (BMI ≥ 30 kg/m² 33.6% vs 26.7%, p = 0.010) with smaller tumour sizes (≥ 50 mm 26.2% vs 31.9%, p = 0.037) when operated via PRLA. Length of hospital stay was shorter (> 2 days 47.4% vs 62.9%, p < 0.001) (Supplementary Table S2).
After propensity score matching, 865 patients could be included in both groups. The predefined possible confounding variables (age, sex, BMI, center experience, and hormonal status) were equally distributed (SMD < 10%) (Supplementary Table S3). Length of hospital stay was shorter after PRLA (> 2 days 45.2% vs 63.0%, p < 0.001). There was no significant difference between LTA and PRLA in terms of conversion rate, morbidity (Clavien-Dindo grade 2 or higher), wound infection, reoperation, or hospital readmission (Table 4).