Graduation Date

Winter 12-14-2018

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Programs

Epidemiology

First Advisor

Shinobu Watanabe-Galloway

Abstract

Liver cancer is the second-leading cause of cancer death, representing roughly 9.1% of all cancer mortality. Of all primary cancers of the liver, hepatocellular carcinoma (HCC) accounts for roughly 85%. HCC has been increasing in the U.S. and other countries. In particular, HCC places a huge burden on the Chinese population, as China alone consists of approximately 50% of the total HCC cases and deaths. In China, chronic hepatitis B virus (HBV) infection is the leading cause for developing HCC. The two challenges in prevention and control of HCC experienced in China are low rates of HCC screening among the high-risk populations and poor adherence to HBV antiviral therapy. As of this date, there is a dearth of research in surveying high-risk populations with chronic viral hepatitis to evaluate the compliance, knowledge level, and self-identified barriers to recommended HCC screening and antiviral medication treatment. In addition to its high incidence and mortality rates in China, HCC is also a major disease burden in the U.S., where HCC is currently the fastest growing cause of cancer-related death. As HCC often leads to poor survival, it is critical to initiate early treatment. Currently, there are no established guidelines to define the optimal time interval from diagnosis to surgery. Knowledge regarding to the impact of HCC treatment delays is solely based on results produced from medical records-based studies conducted in single centers, and findings have been inconsistent. The main objectives of this dissertation are to 1) investigate the practice, knowledge and barriers for HCC screening in high-risk Chinese patients, 2) assess the medication adherence and perceived barriers to oral antiviral therapy for chronic HBV treatment, and 3) utilize the Commission on Cancer’s National Cancer Database to examine the association between surgical treatment delays and long-term survival in HCC patients.

In the results of the first objective, we observed that among 352 high-risk patients for HCC, 50.0% had routine HCC screening, 23.3% had irregular screening and 26.7% had incomplete or no screening. The most frequent barriers reported for not receiving screening were not aware that screening for HCC exists (41.5%), no symptoms or discomfort (38.3%), and lack of recommendation from physicians (31.9%). The results of the second objective showed that among 369 patients with chronic HBV, only 16.5% were measured with high adherence while 51.2% had low adherence utilizing the Morisky Medication Adherence Scale. The most common reasons for skipping HBV antiviral medications were that medication(s) are expensive (48.7%), forgetfulness (45.1%), have experienced or worry about potential side effects (19.8%). The results of the third objective showed that using a wait time cutoff at 60 days from the date of HCC diagnosis to definitive surgery, delayed patients demonstrated significantly better 5-year survival for local tumor destruction (29.1% vs. 27.6%) and hepatic resection (44.1% vs. 41.0%). Risk-adjusted model indicated that delayed patients had a 7% decreased risk of death.

The findings of these studies may assist healthcare providers and researchers to develop more effective educational programs to improve patients’ awareness, knowledge and perceptions about HCC prevention and control, actively identify the high-risk patients for undergoing HCC screening, and provide better disease management and timely treatment for patients with chronic viral hepatitis to decrease the likelihood of developing HCC. For treating HCC patients, using a national hospital-based cancer registry, our study added new evidence that delay in HCC surgery was associated with a decreased risk of mortality. The finding calls for the need to conduct prospective studies to assess the case prioritization approach and its level of impact in HCC surgical care.

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