Rapid Development of Hepatocellular Carcinoma after Eradication of Hepatitis C Virus with Directly Acting Antiviral Treatment

Hepatitis C is a major risk factor for the development of hepatocellular carcinoma (HCC), arising typically on a background of liver cirrhosis. Treatment of hepatitis C has been revolutionized by the addition of oral direct-acting antivirals (DAAs) with sustained virological response (SVR) rates above 90%. There is a recent concern under debate about the increased risk of early HCC recurrence in patients with chronic hepatitis C who were treated with direct-acting antivirals. Nonetheless, these reports mostly focused on patients who were cirrhotic and were already treated for HCC. We report 4 cases of treatment naive, chronic hepatitis C patients who were treated with DAAs and rapidly developed infiltrative HCC despite achieving SVR. Moreover, in our scenario, one of the patients appeared clinically non-cirrhotic until he developed HCC.


Introduction
Chronic Hepatitis C virus (HCV) infected patients with advanced fibrosis/chronic liver disease (CLD) have an overall annual risk of 3.2% for the development of hepatocellular carcinoma (HCC) [1].Antiviral therapy has been available since the early 1990s.However, the SVR rates were unsatisfactory with interferon-based regimens particularly when advanced liver disease sets in [2].Also, the side effect profile of interferon limits its use due to poor compliance [3].Addition of direct-acting antivirals (DAAs) in the armamentarium has increased the HCV cure rates well above 90% even in patients with bridging fibro-sis or cirrhosis, with the additional advantage of avoiding side effects related with interferon.The occurrence of HCC is distinctly less in patients with cirrhosis who achieve sustained virological response (SVR) as compared to those who do not.However, this risk is not completely eliminated even after HCV remedy.
There are case reports describing patients diagnosed with HCC up to 13 and even 20 years after successful antiviral therapy with interferon [4] [5].Out of 500 patients treated with direct-acting antivirals (DAAs) from 2014 to 2017 at the Aga Khan University Hospital, Karachi, we present 4 cases with the rapid development of HCC even after achieving SVR with DAAs, of which all were treatment naive, while one appeared clinically non-cirrhotic until the development of HCC.

Case 1
A 64-year-old male was found to be HCV antibody positive on routine screening in November 2014.He was asymptomatic and physical examination was unremarkable.On investigations complete blood count (CBC) showed hemoglobin (Hb) 14.5 g/dl, total leukocyte count (TLC) 7.He was prescribed sofosbuvir and ribavirin for 24 weeks, which took around 6 months for him to get arranged as it was not freely available in Pakistan at that point in time.Treatment commenced in May 2015.A month after starting DAA, his PCR became negative and remained persistently negative at 3 months of treatment and at the end of treatment (October 2015).He also had improved his diabetic control during that period as his HbA1c improved sequentially to 6.0% and then 4.3% at the end of treatment.At the end of treatment (October 2015), bilirubin was 11 mg/dl, ALT: 18 IU/L, aspartate transaminase (AST): 22 IU/L, Hb: 11.5 g/dl, TLC: 6.6 × 10 9 /L, and platelets: 429 × 10 9 /L.His Fib-4 index was 0.79 while APRI score was 0.147 which ruled out significant fibrosis.Furthermore, he achieved SVR 12 (January 2016) as well as SVR 24 (April 2016) with normal ALT at both occasions.
Triphasic CT scan showed irregular liver margins.A low-density lesion in the left lobe of liver around 50 × 48 mm without any arterial enhancement and it remained low on all three phases of CT (Atypical HCC).A Patchy abnormal arterial enhancement was identified involving segment VI of the liver with washout on portal venous and delayed phase suggestive of infiltrative hepatoma.
The Main portal vein appeared thrombosed with multiple collaterals representing cavernous transformation.Spleen appeared normal while no ascites was seen (Figure 1).admitted with encephalopathy, ascites and hepatorenal syndrome.Due to the guarded prognosis, he was kept for comfort care.Since there was no clinical improvement, the family took the patient home for the end of life care.

Case 2
A 74-year-old hypertensive female was found to be HCV antibody positive on routine screening in October 2014.She was asymptomatic and physical examination was unremarkable.On investigations complete blood count (CBC) showed hemoglobin (Hb) 13 g/dl, TLC 5 × 10 9 /L and platelets 141 × 10 In June 2017, she presented with nausea and weight loss.On examination, she had hepatomegaly with ascites.Repeat ultrasound due to recent onset ascites revealed multiple hypoechoic lesions in the liver, largest measuring 1.5 × 1.2 cm.
Triphasic CT scan showed cirrhotic liver with multicentric HCC in right lobe having an infiltrative pattern, 12 × 9 cm in size, inseparable from the gallbladder.
The right branch of the portal vein was thrombosed.Few lymph nodes were also seen near porta hepatis along with multiple soft tissue nodules in the lung suggestive of metastasis.Moderate ascites and multiple varices were also seen.Her AFP was 1100 IU/ml.
Due to the advance BCLC stage of HCC, options for treatment were very limited.After a detailed discussion with the patient and family members, she was kept on supportive care only.

Case 3
A 42-year-old gentleman with a history of diabetes and hypertension came for evaluation of melena in June 2014.On workup, he was found to have HCV related CLD with grade-III esophageal varices for which he underwent band ligation.He  follow-up.

Discussion
Eradication of HCV plays a key role in the prevention of HCC.A pooled analysis of 25,497 patients from 12 studies confirms that achievement of SVR reduces the risk of HCC (hazard ratio, 0.24 [95% CI, 0.18 -0.31]; p = 0.001), with absolute risk reduction of 4.6% in patients achieving SVR (95% CI, 4.2% -5.0%) [6].Nonetheless, the risk of HCC persists many years after SVR especially in high-risk patient i.e. those with established cirrhosis, old age, and diabetes.Consequently, they require surveillance for HCC despite SVR [7].
A few years back, DAAs were introduced in conjunction with interferon and ribavirin to promote their antiviral potential [8] [9].Later they completely replaced interferon and ribavirin due to their better tolerance, even in older age group and cirrhotic patients, along with better safety profile, and are now considered the first line agents for HCV treatment [10] [11] [12].However, data on long-term outcomes in cirrhotic patients treated with DAAs is still lacking.
A recent "note of caution" was provided by Reig et al. who interestingly showed an increased incidence of HCC with early recurrence after eradication of HCV with interferon-free therapy after successfully treated liver cancer (16 of 58 patients, 28%) [13].This postulate the idea that HCV elimination using DAAs may induce changes in the inflammatory status and immune response to tumors, leading to early recurrence.It is also hypothesized that DAA may enhance the growth of tiny/invisible HCC due to dysregulation of the immune system.This phenomenon is in contrast to interferon treatment which has its own immune-modulatory and anti-proliferative action [14].
Natural killer (NK) cells are the most prevalent innate immune cells in the liver.Chronic HCV infection is known to cause activation of NK cells along with increased expression of interferon-stimulated genes, hence enhancing the intrahepatic immune response.This intrahepatic immune activation is lost in patients treated with DAAs [15] [16].Changes leading to liver regeneration which is associated with cure of inflammation and change in immunologic status can be responsible for the evolution of precancerous lesions into frank malignancy [17] [18].
Above findings of Reig et al. was later supported by few more researchers who confirmed that DAA-induced HCV eradication not only does not reduce HCC occurrence but have a high recurrence rate (29%) within a short period of time (24 weeks) [18] [19] [20].
However, none of the three cohorts of French prospective multicenter ANRS showed an increase in HCC recurrence after DAA treatment in patients who underwent curative HCC therapies [21].This was supported by English data where the author showed a reduction in HCC rate from 4% in untreated patients to 1.9% in patients with virus eradication, over 6 and 9 months respectively [22].
There is no head to head comparison except a retrospective analysis in patients who achieved SVR after interferon/ribavirin treatment vs DAAs treatment showing similar 3 and 5 year cumulative HCC development rates in both groups (1% and 2.2% in Interferon group, and 1.3% and 3% in DAA, respectively) [23].
An indirect comparison of time to recurrence in patients with successfully treated early HCC and active HCV infection with those of patients with SVR by interferon-based and interferon-free regimens showed significantly lower time to recurrence in patients with active HCV infection compared with those with SVR both by interferon-free and interferon-based treatments.However, time to recurrence was similar in patients with SVR by interferon-free or by interferon-base strategies [24].
Reig et al. also raised concern about the pattern of tumor recurrence in patients treated with DAA [13], supported by another Italian cohort of cirrhotic patients who develop infiltrative patterns of HCC [25].
One of our patients was unique in that he achieved SVR and he appeared non-cirrhotic till he developed HCC a year after successful DAA therapy.In all of our patients, there was a rapid development of HCC, supported by recent negative imaging before the actual diagnosis.At the time of diagnosis, the tumor appeared infiltrative on CT scan with portal vein thrombosis making it advance staged.On follow up scan involvement of whole liver parenchyma within 3 months in case 1 also supports the speediness of tumor growth.This supports the concern raised by Reig and Roman in their group of patients.This also suggests that patients treated for HCV, despite being non-cirrhotic, should be kept in surveillance even after achieving SVR [26].Due to the typical finding of tumor on CT scan, a biopsy was not done in any of the above patients.
In conclusion, there is a debatable increased risk of HCC occurrence/early recurrence in patients treated with DAAs.Our case series supports the existing data about the pattern of HCC occurrence after DAA therapy; however, large prospective studies are needed to solve this mystery.

Financial Disclosure
No funding source was involved.

Informed Consent
An informed written consent was obtained from all subjects.