Screening in Familial Non-Medullary Thyroid Cancer (FNMTC) Results in Detection of Low Risk Papillary Thyroid Cancer - a Prospective Cohort Study

Presentation Number: OR22-1
Date of Presentation: April 2nd, 2016

Joanna Klubo-Gwiezdzinska*1, Lily Yang2, Roxanne Merkel3, Dhaval Patel3, Naris Nilubol3, Monica C. Skarulis4, Samira Mercedes Sadowski5 and Electron Kebebew3
1National Institute of Health, Bethesda, MD, 2National Institutes of Health, Bethesda, MD, 3National Cancer Institute, NIH, Bethesda, MD, 4NIH, Bethesda, MD, 5National Cancer Institute, Bethesda, MD

Abstract

Background

Most studies suggest that FNMTC is associated with more aggressive disease than sporadic non-medullary thyroid cancer (NMTC). However, there is no data on the optimal strategy to screen at risk individuals in FNMTC kindred.

 

Methods

We performed a prospective cohort study with yearly screening using thyroid/neck ultrasound (US) and fine needle aspiration biopsy (FNAB) of thyroid nodule(s) > 0.5 cm in at risk members of families with FNMTC.  The eligibility criterion was the presence of NMTC in 2 first-degree relatives and age > 7 years.

 

Results

Twenty five kindred fulfilled our inclusion criteria - 13 families had 3 or more affected members and 12 families had 2 members affected by FNMTC at enrollment. The study group consisted of 171 individuals – 56 patients with an established diagnosis of FNMTC and 115 family members who were unaffected and underwent yearly screening.

Among the screened cohort 100/115 patients underwent yearly thyroid US. Thyroid nodules were present in 48 patients (48%), FNAB was performed in 30 patients with nodules larger than 0.5 cm. Cytology report was non diagnostic in 3 patients, benign - in 15 patients, AUS/FLUS - in 4 patients, follicular neoplasm - in 2 patients and consistent with  papillary thyroid cancer (PTC) in 6 patients.

Twenty one patients were treated surgically. Pathology showed follicular adenoma in 6 and PTC in 15 patients.

PTC was detected by screening only in 2.3% (1/43) of individuals with 2 members affected and 20.9% (14/67) of patients with 3 or more family members affected by FNMTC (p=0.018).

Compared with index cases, FNMTC detected by screening was characterized by smaller tumor size (0.8 cm+/-0.6 vs 1.5+/- 1.1, p= 0.004), lower prevalence of central neck metastases (20% vs 34%, P=0.02), lack of lateral neck metastases (0% vs 12.5%, p=0.1) and lack of gross extrathyroidal extension (0% vs 9%, p=0.3).

Patients with FNMTC detected by screening underwent less aggressive treatment than index cases.  Hemi-thyroidectomy was performed in 13% (2/15) vs 0% (0/56), p=0.04, lateral neck dissection in 0% (0/15) vs 12.5% (7/56), p=0.09, radioactive iodine therapy in 26.6% (4/15) vs 55.3% (31/56), p=0.04 of screened family members vs index cases, respectively. The rate of central neck dissection was similar in both groups (56.6% vs 55.3% p=0.55). FNMTC recurrence rate was  14.3% (8/56) and thyroid cancer specific mortality was 3.6% (2/56) in index cases, but could not be assessed in patients with FNMTC detected by screening due to relatively short duration of follow up of 17+/- 11.7 (3-32 months).

Conclusions

Screening of at risk family members with FNMTC results in detection of low risk PTC and enables less aggressive treatment.   Our study suggests that screening should be performed in kindred with at least 3 members affected by FNMTC and might not be necessary when only 2 members of the family are affected.

 

Nothing to Disclose: JK, LY, RM, DP, NN, MCS, SMS, EK