Tailored management of advanced thyroid cancer patients treated with lenvatinib or vandetanib: the role of a multimodal approach.

BACKGROUND

In differentiated/poorly differentiated (DTC/PDTC) or medullary thyroid cancer (MTC) treated with kinase inhibitors (KIs), additional treatments (ATs) can be performed in selected cases.

METHODS

We retrospectively analysed all the ATs performed in our center in KI-treated TC patients, evaluating the subsequent KI modulation, the local PD in case of loco-regional procedure (LRP) and the AT-related complications. DTC/PDTC patients with or without progressive disease before the first AT (PD and NO PD GROUP, respectively) were analysed separately.

RESULTS

In our center, 32 ATs (30 LRPs and 2 radioactive iodine treatments) were performed in 14 DTC/PDTC patients and 4 MTC subjects after the start of systemic therapy with lenvatinib or vandetanib (27 and 5 ATs, respectively). Brain was the most treated site (11/30 LRPs) and external beam radiation was the most employed LRP (18/30 LRPs). KIs dose reduction or discontinuation of KI therapy (at least transient) was performed after 50% of ATs in DTC/PDTC NO PD GROUP. The KI was maintained at the same dosage after 75% and 50% of the ATs performed in DTC/PDTC PD GROUP and MTC, respectively. During the follow-up, local PD was detected after 14 LRPs. Local progression-free survival (LPFS) was significantly shorter in DTC/PDTC PD GROUP in comparison to NO PD GROUP (12 month-LPFS 91.7% versus 15.2%); in patients with MTC, 12 month-LPFS was 50%. AT-related AEs were mostly G1-G2.

CONCLUSIONS

In selected DTC/PDTC without previous PD and treated with a multimodal strategy, local disease control is generally maintained regardless the KI dose modulation. In DTC/PDTC patients with previous limited PD and in MTC subjects, the choice of performing a LRP and continue the ongoing KI therapy must consider the risk of early local progression. AT-related AEs in KI treated patients were mild in most cases.