Study Finds Decline in Gallbladder Cancer Incidence Among Men, Not Women

A study published in Cancer Medicine shows that rates of gallbladder cancer have been declining since the 1970s among men, but not women. It also found that late-stage cases of the cancer have become increasingly common.

Gallbladder cancer is uncommon, as the incidence rate is 1.4 per 100,000 people and the CDC indicates around 3700 new cases are diagnosed in the US every year. Research on the cancer has been sparse, as studies tend to focus more on surgical interventions than on epidemiological trends and survival rates.

The researchers in this study therefore utilized the Surveillance Epidemiology and End Results (SEER) database to gather information on over 18,000 incidences of gallbladder cancer reported between 1973 and 2009. They found that women are significantly likely to experience this type of cancer, as 71% of patients in these records were female.

Looking at trends across decades, the researchers observed a decrease in gallbladder cancer incidence for both males and females since 1973, but around the mid-1990s, the incidence rate in females halted its decline and leveled off. Another concerning trend was spotted in cancer stage at diagnosis, as the proportion of cancers diagnosed at distant stage had decreased from 1973 until around 2000, when it started to climb upwards.

The proportion of gallbladder cancer cases caught earlier in the localized stage had been increasing until around the mid-1990s, which the authors suggested could be attributed to the increased use of laparoscopic cholecystectomies that allowed clinicians to detect cancer sooner. However, the proportion of localized cases remained relatively level from 2000 to 2009.

The study authors then examined SEER survival data and found that patients’ odds of survival had steadily improved throughout the study period. In particular, survival rates were higher for females than for males and Asian/Pacific Islanders had the highest survival odds of any racial/ethnic group. Patients who received both surgery and radiation were less likely to die of gallbladder cancer or any other cause compared with those who had undergone just 1 or none of the treatments.

In a press release from their institution, the University of Missouri, the authors advised caution in applying these findings to the general public, as foreign-born people and urban residents were overrepresented in the SEER data compared with the US population. Still, they explained, their findings could be used to hone the focus of future investigations.

“Definitely more research will be needed to better understand why gallbladder cancer rates are not decreasing for women as they are with men,” said lead author Jamal Ibdah, MD, PhD. “We also need a better understanding of why late-stage diagnosis is on the rise. However, the information in this study will allow us to focus on these areas so that over time and through clinical trials, we may one day develop a cost-effective, evidence-based screening technique to reverse these trends.”