Association Between BRAF V600E and Redifferentiation Therapy in Patients With Radioiodine-refractory Papillary Thyroid Cancer
Conditions: Thyroid Cancer
Sponsor: Heidelberg University

Association Between BRAF V600E and Redifferentiation Therapy 
in Patients with Radioiodine-refractory Papillary Thyroid Cancer 
 
Tissue samples were provided by the tissue bank of the National Center for Tumor Diseases 
(NCT, Heidelberg, Germany) in accordance with the regulations of the tissue bank and the 
approval of the ethics committee of the University of Heidelberg.  
Local ethics vote number: S-206/2005 
Date of document: 01/05/2015 
 
 
 

Summary 
Papillary thyroid cancer (PTC) is the most common neoplasia in the thyroid gland 1,2. The 
combination of surgery, followed by radioiodine therapy (RIT) and thyroid-stimulating 
hormone (TSH) suppressive therapy is usually a curative option for differentiated thyroid 
cancer (DTC). Although DTC has a good prognosis generally, it is problematic when 
dedifferentiation is suspected and radioiodine refractoriness presumed. One possible therapy 
option for redifferentiation is the pretreatment with retinoids. From 2008 to 2014 there were 
13 patients with PTC who were treated with retinoids after thyroidectomy before a further 
course of radioiodine. A recent study has shown that the efficacy of Selumetinib, another 
option for redifferentiation depends on the mutational status of the treated patient. In this 
retrospective study Groener and Gelen et al. investigated whether there is a similar 
association between BRAF V600E and redifferentiation therapy with retinoids. As retinoids 
have fewer side effects compared to TKI, it is worth performing studies to assess the 
importance of genetic marker for the response and to estimate the chances of this specific 
patient collective. BRAF V600E seems to be associated with better long-term response after 
redifferentiation therapy with 13-cis RA in RAI-R PTC. Therefore, evaluation of BRAF 
mutational status prior to redifferentiation therapy could be beneficial for predicting response. 
 
 
 

1. Participant Flow 
Study design  
The investigators performed a retrospective analysis studying the association between BRAF 
V600E mutation and the response to retinoids at Heidelberg University Hospital. DNA 
sequencing was performed in formalin-fixed paraffin-embedded tissue (FFPE), using 
commercially available kits. Tissue samples were provided by the tissue bank of the National 
Center for Tumor Diseases (NCT, Heidelberg, Germany) in accordance with the regulations 
of the tissue bank and the approval of the ethics committee of the University of Heidelberg 
(local ethics vote number S-206/2005).  
Pre-assignment Details 
Eligibility criteria for radioiodine-refractory (RAI-R) patients included: 
 
PTC 
 
no response to former RIT 
 
decrease or loss of initial sufficient RI-Uptake 
 
redifferentiation therapy with 13-cis-RA 
 
available FFPE tissue.  
 
Eligibility criteria for radioiodine-sensitive (RAI-S) patients included:  
 
PTC 
 
cured after a maximum of two RIT 
 
no redifferentiation therapy necessary 
 
available FFPE tissue.  
 
Exclusion criteria included:  
 
DTC other than PTC 
 
patients lost to follow-up  
 
other redifferentiation therapy than retinoids 
 
anaplastic or medullary thyroid cancer 
 
benign thyroid disease, no available FFPE tissue 
 
more than two RITs in the control group 
 
insufficient clinical information. 
 
Group Information:  
Although almost all (one of 13 patients could not be evaluated) PTC patients treated with 13-
cis RA at the University Hospital of Heidelberg between 2008 and 2014 were included in our 

study, the most important limitation is the small sample size. Different authors indicate that 
there is only a small group of patients with primary or secondary dedifferentiated tumors, who 
are palliative or have a lethal outcome due to refractoriness to standard therapy 3. Due to this 
relative rarity, there are no large randomized studies including a comparable patient cohort 4. 
Twelve patients with radioiodine-refractory papillary thyroid cancer (RAI-R PTC) were treated 
with 13-cis retinoic acid (Isotretinoin, Roaccutan®) for up to two months before another 
course of radioiodine-therapy was applied. Their mutational status was determined to find 
possible associations between BRAF V600E mutation and response to retinoids compared to 
BRAF wild type. Furthermore, their mutational status was compared to a radioiodine-
sensitive control group of twelve PTC (RAI-S PTC) patients.  
 
 
RAI-R PTC group: Thirteen patients with radioiodine refractory papillary thyroid 
cancer who received redifferentiation therapy with 13-cis retinoic acid (RA), followed 
by a further course of iodine-131 treatment (RIT).  
 
 
RAI-S PTC group: This control group consisted of twelve patients who were 
considered cured after a maximum of two RIT and did not need any redifferentiation 
therapy. 
Periods 
Study was divided into three parts: 
 
Period one: Selection of patients with available FFPE tissue and fulfilling of eligibility 
criteria.  
 
Period two: Determination of mutational status by DNA extraction and sequencing. 
 
Period three: Analysis of findings. For assessment of clinical outcome of 13-cis 
retinoic acid treatment three parameters, tumor size, thyroglobulin levels, and 
radioiodine uptake were considered in a graduated model according to existing 
literature. One patient of RAI-R PTC group has to be excluded due to a lack of follow-
up data. 
 
2. Baseline Characteristics 
Table 1 Baseline characteristic of RAI-R PTC and RAI-S PTC 
 
Baseline characteristics 
RAI-R PTC 
control group 
patients [numbers] 
n = 12 
n = 12 
age at initial diagnosis [years] 
57,5 (43-69) 
39 (24-69) 
sex [m/f] (% of total) 
[6/6] (50%/50%) 
[5/7] (42%/58%) 
 
sample material [number of patients] 
 
Primary tumor  
 
6 
 
9 

 
Local recurrence 
 
Nodal metastases 
 
Distant metastases  
1 
5 
2 
0 
6 
0 
T-stage [number of patients] 
 
Tx  
 
T1 (a and b) 
 
T2  
 
T3 
 
T4  
 
0 
1 
1 
8 
2 
 
0 
8 
0 
4 
0 
N-stage [number of patients] 
 
Nx  
 
N0  
 
N1 (a and b)  
 
3 
2 
7 
 
3 
5 
4 
M-stage [number of patients] 
 
Mx  
 
M0 
 
M1 
 
6 
4 
2 
 
6 
6 
0 
previous RITs [number of patients] 
 
no RIT  
 
one RIT 
 
two RIT 
 
>2 RIT 
 
0 
4 
4 
4 
 
10 
2 
n/a 
n/a 
previous redifferentiation 
 
no [number of patients] 
 
yes [number of patients] 
 
duration [days] 
 
12 
0 
59,5 (50-99) 
 
 12 
n/a 
n/a 
RIT dose (GBq) 
 
previous therapy cumulative 
 
current therapy 
 
overall dose cumulative 
 
13,0 (4,0-24,0) 
10,5 (8,0-12,0) 
24,5 (12,0-34,0) 
 
n/a 
n/a 
4,0 (4,0-13,7) 
TSH-stimulation prior therapy 
 
endogenous 
 
endogenous and exogenous 
 
10 
2 
 
12 
0 
Serum Tg prior RIT or  
redifferentiation + RIT [ng/ml] 
1,5 (0,8-55980,0) 
2,2 (0,8-47,3) 
Notes: Tg under not stimulated TSH conditions.  
 
Abbreviations: f female, GBq Gigabecquerel, m male, ml millilitre, n number of patients, ng 
nanogram, n/a not applicable, PTC papillary thyroid cancer, RAI-R radioiodine refractory, RIT 
radioiodine therapy, Tg thyroglobulin, TSH thyroid stimulating hormone  
3. Outcome Measures 
Primary Outcome Measures: 
Response to radioiodine therapy after redifferentiation (Redifferentiation therapy was 
performed using 13-cis RA (Isotretinoin, Roaccutan®) with a daily dose of orally 1,5mg/kg for 
up to two months. 

For assessment of clinical outcome of 13-cis retinoic acid treatment three parameters, tumor 
size, thyroglobulin levels and radioiodine uptake were considered in a graduated model. 
 
Secondary Outcome measures 
First parameter: Tumor size was evaluated form CT, MRI, or FDG-PET/CT imaging, 
comparing results before and after redifferentiation and RIT, results were evaluated using 
Response Evaluation Criteria in Solid Tumors (RECIST).  
 
Second parameter: Non-stimulated serum Tg level (in ng/ml) before redifferentiation therapy 
was compared with the first Tg level after redifferentiation and RIT. A stable Tg level was 
defined as ≤10% difference.  
 
Third parameter: Recovery of RI-Uptake was evaluated from the post-therapy whole body 
scan in comparison to the lesions in CT, MRI, or FDG-PET/CT imaging before 
redifferentiation. Optimal uptake was defined as intensive accumulation of radioiodine in all 
tumor lesions. When not all lesions accumulate radioiodine or the signal was weak it was 
considered as suboptimal uptake.  
Statistical Analysis 
Categorical variables are presented as numbers and percentages. Continuous variables are 
presented as arithmetic mean, median and range. Data were analyzed using IBM SPSS 
Statistics 22 (Ehningen, Germany). Due to the small number of patients in the subgroups, 
descriptive analysis was performed as described before 5-7.  
 
4. Adverse Event Information 
RAI-R PTC group: Nine (75%) patients showed side effects during the period of their 
redifferentiation therapy. Eight (67%) patients reported problems regarding skin and mucosa, 
one patient (8%) stated problems with eye dryness, conjunctivitis, and photosensitivity, one 
patient (8%) suffered from fatigue, and one patient (8%) from coughing. 
5. Limitations and Caveats 
Although almost all (one of 13 patients could not be evaluated) PTC patients treated with 13-
cis RA at the University Hospital of Heidelberg between 2008 and 2014 were included in this 
study, the most important limitation is the small sample size. Furthermore, it must be 
considered that there are other therapeutic options besides retinoids, so that the sample 
size is getting even smaller. A further limitation is the retrospective analysis. The duration of 
follow-up of both groups was not comparable.  

6. Certain Agreements 
Yes: The principal investigator is an employee of the sponsor. 
7. Results Point of Contact 
Central Contact Person: 
Stefan Kopf, MD 
University of Heidelberg 
Division of Endocrinology and Clinical Chemistry 
Im Neuenheimer Feld 410 
69120 Heidelberg 
Germany 
Tel.: 0049-6221-56-37790 
E-Mail: stefan.kopf@med.uni-heidelberg.de 
Central Contact Backup:  
Jan Benedikt Groener, MD  
University of Heidelberg 
Division of Endocrinology and Clinical Chemistry 
Im Neuenheimer Feld 410 
69120 Heidelberg 
Germany 
Tel.: 0049-6221-56-37639 
Fax: 0049-6221-56-4233 
E-Mail: jan.groener@med.uni-heidelberg.de 
 
References 
1. 
Xing M, Alzahrani AS, Carson KA, et al. Association between BRAF V600E mutation 
and recurrence of papillary thyroid cancer. Journal of clinical oncology : official journal of the 
American Society of Clinical Oncology. 2015;33(1):42-50. 
2. 
Liu J, Dong BF, Wang PS, et al. Silencing NOB1 enhances doxorubicin antitumor 
activity of the papillary thyroid carcinoma in vitro and in vivo. Oncol Rep. 2015;33(3):1551-
1559. 
3. 
Mann K, Möller LC, Bockisch A, Quadbeck B, Schmid KW, Janssen OE. 
Chemotherapie beim Schilddrüsenkarzinom. Onkologe. 2005;11(1):78-86. 
4. 
Hussein O, Karen D, Zidan J. Cisplatin based chemotherapy in patients with 
advanced differentiated thyroid carcinoma refractory to I131 treatment. Indian J Med Paediatr 
Oncol. 2013;34(4):234-237. 
5. 
Fernandez CA, Puig-Domingo M, Lomena F, et al. Effectiveness of retinoic acid 

treatment for redifferentiation of thyroid cancer in relation to recovery of radioiodine uptake. J 
Endocrinol Invest. 2009;32(3):228-233. 
6. 
Simon D, Korber C, Krausch M, et al. Clinical impact of retinoids in redifferentiation 
therapy of advanced thyroid cancer: final results of a pilot study. European journal of nuclear 
medicine and molecular imaging. 2002;29(6):775-782. 
7. 
Ho AL, Grewal RK, Leboeuf R, et al. Selumetinib-enhanced radioiodine uptake in 
advanced thyroid cancer. The New England journal of medicine. 2013;368(7):623-632.