Key words
abdomen - hematologic - angiography - interventional procedures
Background
Percutaneous chemosaturation of the liver with melphalan is an innovative option for
the treatment of non-curable primary and secondary liver tumors. Thus, chemosaturation
as a liver-directed, invasive procedure represents an advance in chemoperfusion. Catheter
angiography is used to inject the chemotherapeutic agent melphalan directly into the
hepatic arteries, thereby “saturating” the tissue and thus the predominantly arterially
supplied tumors or metastases (there are no corresponding filter systems for other
chemotherapeutic agents to date). In parallel, venous blood from the liver is aspirated
via a special double balloon catheter in the inferior vena cava and extracorporeally
purified of melphalan via a filter system designed specifically for that drug. The
purified blood is then re-infused via jugular access. In this way, it is possible
to apply very high doses of chemotherapeutic agent to the liver while keeping systemic
side effects low. Melphalan is an alkylating agent that exerts its cytotoxic effect
by incorporating alkyl groups into DNA. In the course of chemosaturation, up to 3 mg/kg
melphalan, calculated on the idealized body weight, is administered (max. 220 mg/therapy
session) [1].
Since the introduction of the currently only approved (CE certified in Germany since
2012) commercial filter system (Delcath Systems inc. NY, USA), several sinle- and
multicenter phase I to phase III studies have been published analyzing the efficacy
of chemosaturation in different tumor entities, leading in hepatic metastatic uveal
melanoma. Even with the filter system of the first generation, a longer survival compared
to best available care was shown in patients with hepatic metastatic uveal melanoma.
Since 2012, the second-generation filter system with improved melphalan extraction
rates has been available, delivering promising results with respect to patient safety
[2]. Chemosaturation can currently be used in Germany as part of studies as well as
an individual treatment attempt.
This review article is intended to provide an overview of recent development as well
as the current status of CS-PHP with regard to patient safety and effectiveness.
Technique
Chemosaturation is performed under general anesthesia and full heparinization (300 IU/kg
body weight heparin with target ACT > 450 s). A heart-lung machine or, more precisely,
a roller pump is required for extracorporeal filtration of the blood. Sheaths are
placed in the right common femoral artery (4F), right common femoral vein (18F), and
right internal jugular vein ([Fig. 1]). For the melphalan injection, a 4F catheter is placed in the celiac trunk or, in
the case of anatomical variants, also in the superior mesenteric artery, for example,
and then a microcatheter is placed in the corresponding hepatic lobe or segmental
artery. A special double balloon catheter (Delcath Systems Inc. NY, USA) is placed
in the inferior vena cava to isolate the hepatic veins. First the cranial and then
the caudal balloon are inflated to isolate the hepatic veins from the systemic circulation.
Blood from the lower half of the body reaches the heart while the inferior vena cava
is blocked (approx. 60–90 minutes) via collaterals such as the azygos and hemiazygos
systems. The tightness of the balloons is verified using digital subtraction angiography
(DSA), demonstrating that special post-processing tools using ROI (region of interest)
to measure the contrast agent leakage between the blocking balloons, can help detect
leaks [3]. These leak checks should be performed prior to initiating melphalan injection and
whenever the arterial catheter is repositioned. The shape and position of the blocking
balloons must be observed during the procedure in order to detect any dislocation
at an early stage ([Fig. 2]). After correct positioning of all catheters, the intra-arterial injection of melphalan
follows, whereby the entire liver is treated; in the case of conditions after liver
resections, the entire remaining liver is treated [4]. Up to 3 mg/kg melphalan, calculated on the idealized body weight, is administered
(max. 220 mg/therapy session) [1].
Fig. 1 Illustration of vascular accesses. Sheaths Right: 18F sheath (white/blue) in the
right common femoral vein and 4F sheath (red) in the right common femoral artery.
Left: 10F return sheath (white/blue) and central venous catheter (green) in the right
internal jugular vein.
Fig. 2 Tightness test of the balloon occlusion of the IVC. DSA to check the tightness of
the balloon occlusion of the IVC without evidence of leakage.
Venous hepatic blood is then extracted via the double balloon catheter, filtered extracorporeally
via a roller pump with filter system operated by a perfusionist and reinfused via
the jugular line. Finally, the heparinization can be antagonized with protamine. According
to the authors’ experience, a therapy session lasts about 120–180 minutes apart from
anesthesia induction and recovery [5]. The patient is monitored in the intensive care unit until the following day, where
the sheaths are removed after the coagulation has completely normalized. The patients
are then usually able to return to the normal ward and can be discharged on the third
to fifth post-interventional day. To prevent tumor lysis syndrome, 300 mg/d allopurinol
is administered for three days postinterventionally. After discharge (outpatient)
laboratory chemical controls are carried out (three times every three days). For control
purposes, an MRI with liver-specific contrast agent is performed after 8 weeks. A
second session is performed if control shows tumor regression or stable disease. In
the authors’ treatment center, up to six chemosaturations have been performed in one
patient. However, up to eight sessions were reported for one patient; thus it can
be concluded that this method is in principle not limited in the frequency of use
if therapy is successful and liver function is preserved [4].
Financial Considerations
The cost of chemosaturation is high and is not covered by the DRG (diagnosis related
group) system’s designated per-case rates. According to the current German OPS catalog
(as of 08/21), chemosaturation is coded as “Percutaneous closed organ perfusion with
chemotherapeutic agents with external blood filter” (8–549.01). The cost of a therapy
session, including material and personnel costs as well as one day’s stay in the intensive
care unit, is approximately €30 000. Although the procedure is established in appropriate
centers and is used with increasing frequency, the costs for it are not generally
covered by health insurance companies due to the lack of direct recommendations for
chemosaturation in current guidelines. This problem can be addressed by applying for
reimbursement prior to initiation of therapy with adequate justification and a clear
statement from an interdisciplinary tumor board explaining the lack of alternative
treatment approaches. However, it should be borne in mind that, from experience, reimbursement
procedures can take up to 4 weeks and, in the event of progression of the tumor disease,
there is a possibility that the patient may subsequently no longer be able to undergo
therapy. The steady increase in published data on chemosaturation provides reason
to hope for simplification of reimbursement in the future.
Patient Safety
Range of side effects
Recent studies show promising data of CS-PHP, but this procedure can be associated
with severe cardiovascular complications, life-threatening bleeding and thromboembolic
events [5]
[6]
[7]. Related circulatory instabilities may occur intraprocedurally, requiring differential
volume and catecholamine administration [8]. Due to the need for strict anticoagulation during the procedure to avoid thrombosis
of the filters (activated clotting time (ACT) target > 450 s), bleeding complications
are reported in the literature in up to 30 % of cases [2]
[9]. These include hematoma at the femoral and cervical puncture sites [10]
[11], femoral hemorrhages and pseudoaneurysms [12]
[13], hemorrhagic gastric ulcers and mucosal hemorrhages [2]
[13]
[14], as well as abdominal and cerebral hemorrhages [9]. Iatrogenic complications of overinfusion and bleeding may cause swelling of the
respiratory tract in rare cases, resulting in delayed extubation and prolonged need
for ICU monitoring [5].
One of the most common complications caused by chemosaturation is melphalan-induced
bone marrow depression, leading to anemia, thrombocytopenia and leukocytopenia [6]. With the introduction of the second generation filtration system in 2012, both
the melphalan extraction rate (from 77 % to 86 %) was increased compared to that of
the first generation, as well as the consistency of filtration performance (from 58 %–95 %
to 71 %–96 %) was improved [6]. However, melphalan-induced bone marrow depression remains a clinically relevant
problem despite improved filters. Thus, Dewald et al. reported clinically relevant
thrombocytopenias in up to 87 % of cases; grade 3/4 anemias occurred in 40 % and leukocytopenia
in 10 % of patients. In the majority of reported cases, these myelosuppressive effects
regenerated within three weeks after the procedure; however, the administration of
platelet and red cell concentrates became necessary in 23 % and 17 % of patients,
respectively [8]. Older studies report similar rates of myelosuppressive complications [6]. To counteract postinterventional neutropenia, Schoenfeld et al. implemented preinterventional
administration of granulocyte colony-stimulating factor (G-CSF) but did not observe
significant improvement [13].
In addition, post-interventional liver damage, which manifests as a transaminase or
bilirubin increase, has been described. Thus, transaminase increases of 7 % and 48 %
were reported [2]
[14]
[15]
[16]
[17]. The rate of clinically relevant hyperbilirubinemia is reported to be up to 15 %
and appears to correlate with tumor burden [13].
A recent study showed that the side effect spectrum does not change even with repeated
sessions (up to six) [5], other data show that up to eight repetitions are possible [4]. Ultimately, the majority of reported adverse events were transient in nature or
manageable, and treatment-associated deaths occurred very rarely (< 1 %) in the published
cohorts (1–15). Accordingly, despite possible complications, both older and recent
studies have concluded that chemosaturation is a safe and effective procedure when
performed with proper patient selection and in the setting of a specialized center,
with experienced radiologists, anesthesiologists, perfusionists (for the pump system),
and intensivists (for postinterventional management) [5]
[10]
[11]
[15]
[18]
[19].
It remains unclear whether high-dose melphalan injections can result in delayed liver
damage or whether the hepatic arterial vascular bed suffers long-term damage. These
issues should be the subject of further studies in the future.
Patient selection
Currently, chemosaturation is a last-line therapy for liver tumors that cannot be
treated curatively, with hepatic metastatic ocular melanoma being of particular importance
[9]. In a recent study, Schönfeld et al. provide detailed recommendations on patient
selection for “salvage therapy” by chemosaturation, derived from the exclusion criteria
of their study: adequate renal and hepatic function (not specified), hemoglobin > 8 g/dL,
leukocytes > 2 tsd/μl; platelets > 50 tsd/μl, serum creatinine > 60 µmol/l, bilirubin
≤ 3 times the upper norm, liver cirrhosis at most Child-Pugh stage A [13]. Hughes et al used the following criteria: Bilirubin < 2.0 mg/dl, platelets > 100 000 µl,
creatinine < 1.5 mg/dl, and liver function test < 10 times normal (neither the exact
test nor the parameters studied were provided) [16]. There are no systematic data regarding the management of potential bleeding sites
such as old strokes or gastric ulcers. It is recommended to treat only patients with
a tumor mass of < 50 % of liver volume to minimize the risk of fulminant tumor decay
syndrome and to ensure adequate liver reserve [19]. However, there is unanimous agreement that the decision to perform chemosaturation
should be discussed individually within the framework of an interdisciplinary tumor
conference.
Effectiveness
Overview
Currently, extensive efforts are underway to systematically collect data and prepare
clinical studies on chemosaturation. There are multiple patient safety and feasibility
studies, as well as phase I and phase II studies in the context of primary and secondary
hepatic neoplasms. As of 12/2020, Europe-wide published expertise includes more than
650 chemosaturations in more than 300 patients, with the largest proportion of procedures
performed for liver metastases of ocular melanoma (489 procedures in 221 patients),
followed by cholangiocellular carcinoma (76 procedures in 42 patients) [20]. According to manufacturer data, over 160 procedures were performed across Europe
in 2021 (personal communication from 01/2022). The following is an overview of the
therapeutic efficacy of chemosaturation.
Hepatic metastatic ocular melanoma
Surgical resection is recommended for the treatment of hepatic metastatic ocular melanoma
in the corresponding S3 guideline (grade B), if it is feasible as R0 resection. No
recommendation on adjuvant procedures can be provided due to a lack of data [21].
The majority of published studies describe the efficacy of chemosaturation in non-resectable
hepatic metastatic ocular melanoma. This disease is particularly suitable for chemosaturation
because it often shows isolated liver metastases that are accessible to the liver-directed
regional area of chemosaturation action and are sensitive to melphalan [22]
[23] ([Fig. 3]). In the case of liver metastasis, ocular melanomas are associated with a median
overall survival (OS) of 8 months from diagnosis [24]
[25]
[26]; systemic therapy options are limited [27]
[28]. Although immune checkpoint inhibitors have led to significantly increased 5-year
overall survival rates of 34 %–53 % in metastatic cutaneous melanoma, they have resulted
in an OS of only 10 months in metastatic ocular melanoma. Other transarterial procedures,
such as selective internal radiotherapy (SIRT) or transarterial chemoembolization
(TACE), are considered safe and result in a mean OS of 8–10 months and 4–9 months
[29]
[30]
[31]
[32]. A recently published prospective phase II study provides promising data on SIRT
in patients with ocular melanoma with a mean OS of 19.2 months [33]. So far, there are no comparative studies on SIRT vs. CS-PHP. The optimal frequency
of CS-PHP use has not yet been defined. In this context, it is interesting to see
whether regular sequential use of CS-PHP can lead to continued stabilization or remission.
Here, in a case collection from our center, we showed that in the majority of patients
with OM, treatment at 6–8 week intervals leads to a response [34].
Fig. 3 Therapeutic response after chemosaturation. Image example of a patient with diffuse
hepatic metastasis of ocular melanoma. The figure shows a metastasis of > 10 cm in
liver segment VII/VIII, and additional disseminated metastases were present on both
sides (not shown). T1 VIBE post-contrast, hepatobiliary phase. a status before therapy, b 8 weeks after first chemosaturation: reduction of tumor burden by > 50 %, c 10 weeks after second chemosaturation: reduction of tumor burden by 43 %, d and e respectively 10 weeks after third and fourth chemosaturation: stable disease in each
case.
In multiple phase III studies, CS-PHP with melphalan achieved median OS to 27 months
and median hepatic progression-free survival (hPFS) up to 11 months [11]
[15]
[18]. In a prospective randomized multicenter trial, Hughes et al. found an hPFS of 7
months in the chemosaturation group and 1.6 months in the best available care (BAC)
group. However, no significant differences were found with respect to OS, and the
study is not informative with respect to the comparison of OS due to crossover between
subgroups ([Table 1]) [16]. Currently, a randomized phase I/II study is in progress comparing chemosaturation
in combination with ipilimumab/nivolumab versus chemosaturation alone (NCT04 283 890).
In addition, another phase III trial (FOCUS) of CS-PHP in ocular melanoma is under
way, involving approximately 40 centers in the U.S. and Europe (NCT02 678 572).
Table 1
Overview of studies about CS-PHP in patients with hepatic metastasis of uveal melanoma.
Authors
|
Publication year
|
Title
|
Study design
|
Number of patients
|
Mean number of chemosaturations
|
Mean hepatic non-progressive survival
|
Mean survival
|
Best response
(Number of patients)
|
Kirstein et al.
|
2017
|
Safety and efficacy of chemosaturation in patients with primary and secondary liver
tumors
|
Retrospective, single-center
|
12
|
n.a.
|
117 days
|
n.a.
|
PR (4)
|
Vogl et al.
|
2017
|
Percutaneous Isolated Hepatic Perfusion as a Treatment for Isolated Hepatic Metastases
of Uveal Melanoma: Patient Outcome and Safety in a Multi-centre Study
|
Retrospective, multicenter
|
18
|
n.a.
|
9.6 months
|
12.4 months
|
PR (8)
|
Karydis et al.
|
2018
|
Percutaneous hepatic perfusion with melphalan in uveal melanoma: A safe and effective
treatment modality in an orphan disease
|
Retrospective, multicenter
|
51
|
n.a.
|
9.1 months
|
15.3 months
|
CR (3)
|
Brüning et al.
|
2020
|
Unresectable Hepatic Metastasis of Uveal Melanoma: Hepatic Chemosaturation with High-Dose
Melphalan—Long-Term Overall Survival Negatively Correlates with Tumor Burden
|
Retrospective, single-center
|
19
|
2
|
n.a.
|
16.7 months
|
PR (10)
|
Hughes et al.
|
2016
|
Results of a Randomized Controlled Multicenter Phase III Trial of Percutaneous Hepatic
Perfusion Compared with Best Available Care for Patients with Melanoma Liver Metastases
|
Prospective, multicenter
|
44
|
3
|
7 months
|
10.6 months
|
PR (16)
|
Schönfeld et al.
|
2020
|
Chemosaturation with percutaneous hepatic perfusion is effective in patients with
ocular melanoma and cholangiocarcinoma
|
Retrospective, single-center
|
30
|
|
6 months
|
12 months
|
PR (11)
|
Veelken et al.
|
2021
|
Repeated percutaneous hepatic perfusion with melphalan can maintain long-term response
in patients with liver cancers
|
Retrospective, single-center
|
13
|
3
|
326 days
|
n.a.
|
CR (3)
|
Cholangiocellular carcinoma
Resection is the only curative treatment for intrahepatic cholangiocellular carcinoma
(ICC), but the majority of ICC cases is already inoperable at diagnosis, making only
10–35 % of patients eligible for resection [35]
[36]
[37]
[38]
[39]. As with hepatic metastatic ocular melanoma, systemic therapy options for ICC are
very limited [36]
[40]. According to the guideline, all inoperable patients with adequate general condition
should be offered systemic therapy, in which a combination of gemcitabine and cisplatin
represents the first line and FOLFOX the second line; chemosaturation may be offered
if the second line fails [41]. Other transarterial forms of therapy such as SIRT and TACE seem to play a potential
role in neoadjuvant concepts or multimodal therapies (e. g. SIRT in combination with
systemic chemotherapy) [42].
In 2017, Kirstein et al. in a retrospective analysis described five patients with
ICC who were treated by chemosaturation; in these cases an OS of 8 months and hPFS
of 135 days were reported [18]. In a more recent study, chemosaturations were evaluated in 15 patients with ICC;
local tumor control was achieved in 53 % of cases (OS was 26.9 months after diagnosis
and 7.9 months after initial chemosaturation, hPFS was 131 days). Surprisingly, patients
with only liver involvement showed a poorer OS than patients with lymph node involvement
(12.9 vs. 4.8 months), although the hepatic tumor volume in the groups was not provided
in the study [10]. Schoenfeld et al. report on 14 ICC patients treated with chemosaturation and found
a complete remission in one case; the longest OS in one patient was 3.7 years after
chemosaturation, followed by 3.4 years, 2.8 years and 2.3 years. Three patients are
still under therapy and observation [13]. Forty European centers are currently participating in a randomized controlled phase
III study on the effectiveness, safety and pharmacokinetic aspects comparing chemosaturation
after systemic therapy with cisplatin/gemcitabine versus systemic therapy with cisplatin/gemcitabine
alone (NCT03 086 993).
Other tumor entities
Compared to that on ocular melanoma and ICC the data on other tumor entities is significantly
limited. By 12/2020, 95 chemosaturations had been documented across Europe in 58 patients
for tumors other than ocular melanoma and ICC. Of these, 24 chemosaturations were
to colorectal liver metastases, 20 to hepatocellular carcinomas, 14 to liver metastases
from pancreatic carcinomas, and 37 to neuroendocrine tumors, cutaneous melanomas,
breast carcinomas, and other tumors [2]
[9]
[10]
[16]
[17]
[18]
[20]
[43]. All these treatments have in common that they were performed in patients for whom
other established forms of therapy had already failed; accordingly the results are
very heterogeneous and of only limited significance. Forster and colleagues report
that a partial response was achieved in a patient with hepatic metastatic sarcoma
[7]. A 2014 paper describes six patients with cutaneous melanoma who achieved complete
remission (n = 3) or partial response (n = 3); in addition the study described one
patient with liver metastases from breast cancer and one patient with hepatic metastatic
gastric cancer, both of whom achieved a partial response [14]. To date, there are no systematic analyses of patients with the above-mentioned
tumor types with sufficient case numbers to make a sound statement on the efficacy
of chemosaturation in this context.
Predicting effectiveness
Regarding the predictability of response to therapy, Brüning et al. showed in a recent
paper that tumor volume before initiation of therapy correlates negatively with median
survival, whereby a threshold of > 50 % tumor relative to liver volume is specified
[12]. Estler et al. demonstrated that a tumor burden of < 25 % of liver volume is associated
with significantly longer OS [44].
Summary
Liver chemosaturation with melphalan is an innovative treatment procedure for the
treatment of primary and secondary liver malignancies. Although data are already available
for hepatic metastatic ocular melanoma demonstrating the strong efficacy of this treatment
in many patients, there is no high-level evidence yet for other tumors, but there
are numerous promising case collections and anecdotal reports. Therefore, the use
of this method is currently the subject of intensive research.
A solid body of data is available on patient safety and periprocedural management.
Even with the second-generation filter system, intra- and postprocedural anemias,
thrombopenias, and leukocytopenias are to be expected and may be the result of transient
bone marrow depression due to high-dose melphalan application. In addition, transient
liver dysfunction with transaminase elevations and hyperbilirubinemia may occur. Despite
the possible complications, chemosaturation is a safe and effective procedure when
performed with appropriate patient selection in specialized institutions. It can be
stated that chemosaturation represents a promising procedure for the treatment of
unresectable liver metastases of ocular melanomas and of cholangiocellular carcinomas,
which requires close interdisciplinary collaboration. Patients with a diffuse hepatic
involvement with a tumor mass of > 50 % of the liver volume seem to benefit from the
therapy. Multiple studies have shown that chemosaturation in this setting can significantly
prolong median survival as well as median progression-free survival. Promising data
exist to some extent on other hepatic neoplasms, but there are few systematic analyses.
Studies are currently underway that shed light on the benefits of chemosaturation
in combination with systemic therapies.