Discussion
This patient underwent a resection of her trachea in 2017 for reportedly
HPV positive squamous cell carcinoma (SCC). She was then lost to
follow-up and received no treatment up until 2020, when she reappeared
with stridor and a significantly obstructing tracheal mass just below
the thoracic inlet, with apparent transmural invasion and involvement of
at least the esophageal adventitia. In turn, mechanical ventilation
could not be performed.
This SCC was a typical pattern HPV tumor with clear confirmation by
diffuse nuclear cytoplasmic p16 immunohistochemical positivity. The
PD-L1 for Keytruda (Pembrolizumab) was positive with a combined positive
score (CPS) of 15. The PD-L1 for Opdivo was also positive. Pembrolizumab
is a selective humanized IgG4 kappa monoclonal antibody that inhibits
the programmed death-1 (PD-1) receptor, an integral component of immune
checkpoint regulation in the tumor microenvironment9.
The PD‑L1 and PD‑L2 ligands on tumors can bind with PD-1 receptors on T
cells to inactivate them9. Pembrolizumab binds to
the PD-1 receptor and blocks its interaction with PD‑L1 and PD‑L2, which
helps to restore the immune response9. The drug is
currently approved by the Food and Drug Administration (FDA) for the
treatment of metastatic or unresectable, recurrent head and neck SCC
whose tumors express PD-L1 [CPS >=1], with disease
progression on or after platinum-containing chemotherapy. It has also
been approved for treatment of advanced melanoma and metastatic squamous
and nonsquamous non-small cell lung cancer (NSCLC)9.
Ultimately, according to a 2015 study by Bowman, the greatest value to
be derived from tracking PD-L1 testing is the ability to link test
results to treatment decisions10.
As of May 15, there has been no recurrence of the symptoms since
surgery, and imaging shows a clear and patent trachea. The implications
of PD-L1 staining in this patient and subsequent choice of chemotherapy
will continue to be evaluated throughout the patient follow-up period.
Regarding the decision to not use any form of anticoagulation during the
procedure, blood loss was minimal, less than 10 mL. There also were no
thrombotic or hemorrhagic complications during or after this surgery.
Based off of these positive results, we recommend that anticoagulation
and its possible benefits and negative side effects be considered in
full effect for any procedure dealing with a small opening in a head and
neck procedure. For our group, the potentially catastrophic
mid-procedure outcomes from use of anticoagulation caused us to decide
against its use, especially given the very small opening through which
the tracheal procedure occurred. In sum, the ultimate fear for our group
was that intraoperative bleeding in the small operative space would lead
to an inability to continue and successfully complete the operation.
With limited visualization, the resection of 90 percent of the tracheal
mass would not have been possible. As mentioned above for the PD-L1
staining, thrombotic and hemorrhagic events will continue to be at
forefront of our minds during this postoperative and follow-up period.
We will continue to monitor the patient and check for any changes or
discrepancies in her CBC, BMP, and clotting factors.