MATERIALS AND
METHODS
Patients and
treatment
Six patients with germinoma treated in our institute from 2007 to 2018
were included in the study. All three hCG-related markers (hCGβ, intact
hCG, and total hCG) were measured. The clinical characteristics of the
six patients are summarized in Table 1. The median age of the patients
was 15 years. The tumors were located at the pineal (n = 2),
neurohypophyseal (n = 2), and basal ganglia regions (n = 2). For
diagnosis, the patients underwent endoscopic biopsies, stereotactic
needle biopsies, or craniotomies.
All patients were treated with platinum-based chemotherapy and
radiotherapy. The irradiation fields were the whole ventricles in four
patients and the whole brain in two patients with basal ganglia lesions.
Chemotherapy consisted of carboplatin (450 mg/m2) on
Day 1 and etoposide (150 mg/m2/day) on days 1–3.
Patients received three cycles of chemotherapy at an interval of
28 days.11
Measurement of
hCG
The blood samples of the patients were collected, and the three markers
were measured before, during, and after treatment together with AFP to
exclude nongerminomatous germ cell tumors. One patient was additionally
measured with the hCGβ and total hCG during recurrence 2 years after the
initial treatment (Case 2).
hCGβ, intact hCG, and total hCG were measured using the radioimmunoassay
(Ball ELSA·F-βHCG kit, Cisbio Bioassays, France),
electrochemiluminescent immunoassay (ECLusys HCG II STAT, Roche
Diagnostics, Japan), and chemiluminescent immunoassay (Architect βhCG,
Abbott Japan), respectively. The lower detection limits of hCGβ, intact
hCG, and total hCG were 0.1 ng/mL, 0.5 mIU/mL, and 1.2 mIU/mL
respectively, based on the manufacturers’ protocols. The lower limit of
the normal range of AFP was 10.0 ng/mL.
Statistical
analysis
For statistical analyses, group comparisons were performed using
Friedman’s test with Bonferroni’s multiple comparisons test for the
values of the samples and Cochran’s Q and McNemar tests for the
positivity rates. All statistical analyses were calculated with EZR
(Saitama Medical Center, Jichi Medical University, Saitama, Japan),
which is a graphical user interface for R (The R Foundation for
Statistical Computing, Vienna, Austria). More precisely, it is a
modified version of R commander designed to add statistical functions
frequently used in biostatistics.12 This investigation
was approved by the ethical committee of the Saitama Medical University
International Medical Center (Approval number: 19-032).