Subjects:
A prospective cohort study of 84 cHL patients was carried out. All patients were met the following criteria: pathologically confirmed cHL based on immunohistochemistry IHC),age more than 16 years, they haven’t previous treatment, no previous history of malignancy, transplantation or immunosuppression, no human immune deficiency virus infection and treatment with combination Chemotherapy (ABVD) with Radiation. Therapeutic decision was made based on the EORTC classification, patients with early stage favorable HL (stages I,II without risk factors) treated with 2 cycles of ABVD and radiotherapy therapy (20-30 Gy), patients with early stage unfavorable HL (stages I,II with risk factors) treated with 4 cycles of ABVD and radiotherapy therapy (20-30 Gy) and patients with advanced stage HL (stages III,IV) treated with 6 cycles of ABVD and radiotherapy therapy (20-30 Gy).
The data were prospectively collected from June 1st, 2020 to January 31st, 2021. Ethical approval was obtained from institutional review board of Tishreen University Hospital Number (2374) and written consents were obtained from patients. For patients aged 16 and 17 years, the consents were signed by the parents. The study was performed in accordance with the 1964 Declaration of Helsinki and its later amendments. And was registered on the website (https://clinicaltrials.gov/) under number (NCT04893538).
Examination and analyses:
CBC and serum Albumin assay were performed at the time of diagnosis and before treatment given. CBC with 5 parts differential counts was measured using hematology analyzer, Sysmex XT-1800i (Sysmex, Kobe, Jaban), while the Alb was measured using a chemistry analyzer, Mindray BS-380 (Mindray, Shenzhen, P.R. China). ALC and LMR were obtained from CBC. IPS was obtained from general information about the patient (age, gender, Ann arbor staging) and from CBC results (Hb level, ALC, WBC) and serum Albumin results.
The patient cohorts consisted 3 subgroups: ALC group, LMR group and IPS group. For ALC group the exposed subjects were whose have ALC less than 1500 cell/mcL and control subjects were whose have ALC of 1500 cell/mcL or more. For LMR group subjects whose have LMR less than 2.9 were considered exposed group and who have LMR of 2.9 or more were the control group. For IPS group the exposed subjects were who have score of 3 or more and the control subjects were who have score less than 3.
Pilot study:
There were differences between previous study in terms of cut-off values of ALC and LMR as the table (1) shows.
Table (1): Difference in cut-off points between studies
researcher
|
indicator
|
Cut-off point
|
country
|
date
|
Hancock BW
|
ALC
|
1500 cell/ mcL
|
United Kingdom
|
1982
|
Hasenclever D
|
ALC
|
600 cell/ mcL
|
Germany
|
1998
|
Koh YW
|
ALC
|
1100 cell/ mcL
|
South Korea
|
2012
|
Tarsheen K
|
ALC
|
1000 cell/ mcL
|
USA
|
2015
|
Porrata L
|
LMR
|
1.1
|
USA
|
2011
|
Koh YW
|
LMR
|
2.8
|
South Korea
|
2012
|
Simon Z
|
LMR
|
2.11
|
Hungary
|
2015
|
Jakovic R
|
LMR
|
2
|
Serbia
|
2016
|
Romano A
|
LMR
|
2
|
Italy
|
2018
|
Tao J
|
LMR
|
2.5
|
China
|
2019
|
In our study, there was a really need to conduct a pilot study to determine the appropriate cut-off values for patients in this study. This pilot study was also used in order to determine the appropriate simple size. This pilot study was retrospective case control analysis. It included 136 HL patients. receiver operating characteristics curve analysis showed that: the ALC of 1500 cell/mcL represents the best cut-off point between good and bad prognosis patients. Likewise, LMR of 2.9 was showed as the best cut-off point. For IPS: we could not study the best cut-off point suitable for our patients because the pilot study data did not include Albumin analysis results. Therefore, we relied on what is found in the medical literature, we considered that IPS of 3 represent the best cut-off point [9, 10].
Sample size was calculated using G power (3.1.9.4). The total sample size of 73 patients gives the least acceptable power for the study of 80%.
End points and Follow-up:
Patients were examined every two weeks during treatment period. After completion of the treatment, all patients were followed up every 3 months for 18 months. CT scan was carried out in the middle and at the end of treatment and every 3 months afterward. The end points were Response to treatment, Progression Free Survival (PFS) and Overall Survival (OS). Response to treatment was defined as achieving Complete Remission (CR) after receiving the prescribed treatment plan. Complete Remission was defined according Computed Tomography-Based Lugano's classification [11]. PFS was defined as the length of time during and after the treatment of HL, that a patient lives with the disease without getting worse. OS was defined as the length of time from the date of diagnosis the HL, that patients are still alive.
Statistical analysis:
Chi_Squared test (or Fisher's exact test, if indicated) was used for categorical variables. Survival Curves for PFS and OS were performed using Kaplan_Meier method. Cox proportional hazards model was used to estimate the HR and 95% CI. Proportional hazard assumption was evaluated graphically using log_minus log plots. Any result with P_value < 0.05 was considered to be statistically significant. Furthermore, Propensity Score Matching (PSM) was performed (and correlogram created) using R version 4.1.0 (the R foundation of statistical computing, vienna, Austria) to homogenize the groups and adjust possible bias and confounders. Variables that were used to calculate the PS index were age, sex, Ann arbor stage, histologic subtype, Albumin level, Hemoglobin level, WBC count, Monocytes count, neutrophils count, Platelets count, eosinophils count, ESR, LDH. PSM was carried out using the nearest neighbor 1:1 matching in MatchIt package. (Also, acorrelogram illustrating the correlation between variables was created under the corrplot pacckage.). The ability of three indicators to predict therapeutic response was evaluated through these properties:
Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR+,LR- ), Diagnostic Effectiveness, Relative Risk (RR).