Corresponding author
Mr Tristan Boam
Department of Paediatric Surgery, Leicester Royal Infirmary, Infirmary
Square, Leicester, LE1 5WW, UK
tristanboam@doctors.org.uk
+447708825281
Word count: 401
Number of tables/figures/materials: 0
Running title: Outcomes of incomplete thrombectomy in Wilms tumour
Keywords: Wilms; intravascular; thrombus; thrombectomy; cavectomy;
cavotomy
Dear Editor,
A recent meta-analysis study exploring Inferior Vena Cava (IVC) thrombus
viability following chemotherapy in Wilms tumour (WT) found thrombus
non-viability in some 50% of cases.[1] The risks of IVC
thrombectomy should therefore be weighed against the potential outcomes
of incomplete resection.
Surgeons attempt thrombectomy with reportedly good outcomes with
relatively few studies alleging thrombus left in situ.[2–5]
However, where full extirpative resection is considered unfavourable,
disease is upstaged with adjuvant caval irradiation mandated by current
UK WT and COG guidelines. It is currently unclear whether this strategy
achieves sufficient disease control to make caval surgery unnecessary.
Highlighting this dilemma, non-viable thrombus was found in 5 of 7 of
Ritchey’s 1993 NWTS patients receiving pre-operative radiotherapy
compared to malignant thrombus after 10 weeks neoadjuvant chemotherapy
and radiotherapy in Renaud’s single case.[6, 7]
Extirpative surgery for IVC thrombus carries potentially lethal risks.
In the UK WT3 study, 8 cases of significant bleeding with three
associated case fatalities were recorded.[8] Fatal haemorrhage
following attempts to resect an adherent hepatic vein thrombus has also
been described.[9, 10] These reports are likely an underscored
representation of the true incidence of major haemorrhage.
A concern of incomplete thrombectomy is increased danger of relapse or
recurrence in the vascular or thoracic compartments, however extent of
risk remains contentious.
In a meta-analysis we presented 8 reports on the recorded outcomes of
incomplete resection. Of two studies (n=5[11], n=6[12]) authors
reported individual incidences of pulmonary[11] and peritoneal
relapse,[12] whilst 3 publications showed lung metastases
(n=4/13)[13]; relapse (n=2/18)[2]; and mortalities from
progressive disease (n=6/10)[5] following incomplete resection. A
single study reported 2 sudden deaths which were not clearly linked to
known residual thrombus.[4] Loh et al postulated that complete IVC
occlusion is a better predictor of adverse physiological outcome than
completeness of thrombus resection,[14] Imle reported a good outcome
for their single case of incomplete resection of extensive
thrombus.[3] Since our original publication, IMPORT has reported
outcomes of patients with intravascular extension. Tumour-related deaths
and most relapses were associated with viable thrombus with macroscopic
incomplete resection. Event-free survival was worse, but overall
survival was unaffected when associated with incomplete
thrombectomy.[1, 15]
It is crucial that we evaluate risks and benefits to patients and
families when considering aggressive oncological surgery. Future studies
are obligatory to establish if incomplete resection and adjuvant
chemoradiotherapy are preferable to thrombectomy in complex cases. A
surgeon led co-operative trial may provide a definitive answer.