The OBR Blog

May 17, 2017 - 09:05 pm comments0 Comments

It's ASCO time again! As the 2017 Annual Meeting of ASCO rolls around, a pre-meeting presscast was held to highlight 6 abstracts of importance. The topics included the positive impact of lifestyle interventions on survival in colorectal cancer (CRC), delaying recurrence with adjuvant gefitinib in EGFR-positive non-small-cell lung cancer (NSCLC), adjuvant capecitabine as a new standard of care for biliary tract cancers, and two epidemiology studies: one on the positive impact of human papillomavirus (HPV) vaccination on the prevalence of oral HPV infection, and another showing that the Affordable Care Act has led to increased cancer diagnoses at earlier stages of disease when they are treatable.

Lifestyle Changes and CRC

A healthier lifestyle appears to improve survival in CRC, according to two prospective studies. Eating more tree nuts (but not peanuts or peanut butter) was associated with reduced risk of recurrence and death for patients with stage III CRC. This prospective study included 826 patients with stage III CRC who reported on dietary intake with food frequency questionnaires as part of a randomized adjuvant chemotherapy trial. Compared with patients who abstained from nuts, those who ate at least 2 servings of nuts per week were 42% more likely not to recur and 57% more likely not to die. Lead author was Temidayo Fadelu, MD, Dana-Farber Cancer Center, Boston.

A second prospective study of the same cohort of patients enrolled in the randomized adjuvant chemotherapy trial found that CRC patients who followed the 2012 American Cancer Society (ACS) Nutrition and Physical Activity Guidelines (maintaining a healthy weight, being physically active 1 hour a day 5 days a week, eating a healthy diet rich in fruits and vegetables and whole grains) had prolonged disease-free survival (DFS) and overall survival (OS) compared with patients who did not adopt these behaviors.

Over a median follow-up of 7 years, 335 patients recurred and 299 died. Patients completed behavior surveys at baseline and at 6 months. Patients who had a score that showed good adherence to the ACS guidelines had a 42% lower risk of recurrence and death. When moderate intake of alcohol (1 drink per day for women; 2 drinks per day for men) was factored in, patients with good adherence to the ACS guidelines had a 68% reduced risk of recurrence and death. Lead author was Erin Van Blarigan, ScD, UCSF, California.

"Both studies show that we can be optimistic for patients with early stage CRC. Chemotherapy and surgery can improve overall survival and there is a pretty good chance of surviving if patients maintain a healthy lifestyle," said ASCO President Daniel E. Hayes. Dr. Hayes stressed that these findings do not suggest that patients with early stage CRC should forego standard treatment with chemotherapy and surgery.

"The fact that these were prospective observational studies removes the inherent bias of retrospective studies that rely on memory," Dr. Hayes added. "This makes these findings more compelling."

Adjuvant Gefinitib

EGFR-tyrosine kinase inhibitors (TKI) are standard first-line treatment for EGFR-mutated advanced lung cancer. Adjuvant EGFR-TKI targeted therapy with gefinitib (used earlier in the course of disease) delayed recurrence compared with standard cisplatin-containing chemotherapy in a randomized, Phase 3 trial of 220 patients with stage II-IIIA, EGFR-positive, completely resected NSCLC. Patients who received daily gefitinib for 24 months had a significantly longer disease-free survival (DFS) compared with those treated with 4 cycles of standard chemotherapy: 28.7 months vs 18 months, respectively (P=.005). Adverse events, including Grade 3 and 4, were more frequent in the chemotherapy arm.

This is the first randomized trial to compare these two therapies in patients with EGFR mutations. Results suggest that gefitinib should be considered as an important option for this group of patients, and that routine EGFR testing should be considered in these earlier stage lung cancers, according to lead author Yi-Long Wu, MD, Guangdoong Lung Cancer Institute, Guangdong General Hospital, Guangzhou, China.

ASCO President-Elect Bruce Johnson, MD, said, "The disease-free survival was superior for gefitinib in this trial, but ultimately we are interested in the survival results [before we change practice]. Dr. Wu is planning a survival analysis and I will follow that closely."

Richard Schilsky, MD, ASCO spokesperson, said that EGFR testing is typically done at later stages of NSCLC. "If this turns out to be a treatment option, we will begin testing for EGFR earlier in the course of disease."

Adjuvant Capecitabine

Adjuvant capecitabine extended OS by a median of 17 months compared with surgery alone in patients with biliary tract cancers (occurring in bile ducts inside and outside of the liver and gallbladder). From March 2006 to December 2014, the study randomized 447 patients to capecitabine for 6 months or observation. More than 80% of patients were monitored and followed for 3 years after surgery. Median survival was 51 months in the capecitabine group vs 36 months in the observation group, reflecting a 20% lower likelihood of death, which was not significant in an intent-to-treat analysis (P=.097). However, a per protocol analysis found a statistically significant 25% reduction in death for capecitabine vs observation (53 months vs 36 months; P=.028).

Toxicity was relatively modest with little difference in quality of life between the two arms.

"This is the first trial to enroll a sufficient number of patients to show that chemotherapy after surgery can have a significant improvement in survival with modest side effects, and should be a new standard of care," said John N. Primrose, MD, Professor of Surgery at the University of Southampton, U.K.

"This is an impressive study that represents an enormous amount of work. Biliary tract cancer is more common in Asia than in the Western world and we don't know if these results are generalizable to Asia," said Dr. Hayes .

HPV Vaccination

Although it is well known that the HPV vaccine can prevent the development of HPV-positive cancer, vaccine uptake in the U.S. is suboptimal. One of the first large studies to evaluate the impact of HPV vaccine on oral HPV infection (a risk factor for oropharyngeal cancer) showed that the prevalence of high-risk HPV infection was 88% lower among young adults in the U.S. who reported getting at least 1 vaccine dose than among those who were not vaccinated.

"Rates of HPV-caused oral cancers continue to rise every year in the U.S., particularly among men. And yet, no clinical trial has evaluated the potential use of the HPV vaccine for the prevention of oral HPV infections that could lead to cancer," said senior study author Maura L. Gillison, MD, PhD, now professor at the University of Texas MD Anderson Cancer Center in Houston. Dr. Gillison led this research when she was at Ohio State University.

The study was based on 2627 young adults ages 18-33 during the period 2011-2014 who were part of the National Health and Nutrition Examination Survey (NHANES) from 2009 through 2016. An important finding was that fewer than 1 in 5 young adults (18.3%) received at least 1 dose of the vaccine before age 26. The vaccine rate was only 6.9% among males vs 29.2% among females.

Prevalence of oral HPV infection was lower among vaccinated people vs unvaccinated people: 0.11% vs 1.61%, respectively (P=.008), for an 88% reduction in prevalence. Among men, the prevalence of oral HPV infection was zero in those vaccinated vs 2.1% in the non-vaccinated group (P=.007).

Because of the low uptake of the vaccine in at-risk youth, only a modest effect of the vaccine could be shown on the prevalence of the types of oral HPV infections covered by the vaccine. With current uptake rates, the vaccine reduced the prevalence of vaccine-covered, oral HPV infections by 17% in the overall general population.

"This vaccine has tremendous potential to prevent oral HPV infection associated with cancer. It is estimated that if 1 million people had this vaccine, it could prevent more than 900,000 from having oral HPV infection," stated Dr. Gillison .

ASCO President-Elect Bruce E. Johnson, MD, FASCO stated: "The HPV vaccine has the potential to be one of the most significant cancer prevention tools ever developed, and it's already reducing the world's burden of cervical cancers. The hope is that vaccination will also curb rising rates of HPV-related oral and genital cancers, which are hard to treat. This study confirms that the HPV vaccine can prevent oral HPV infections, but we know it only works if it's used."

Cancers Diagnosed Earlier

More cancers were diagnosed earlier at a more treatable stage after full implementation of the Affordable Care Act (ACA) in 2014. An analysis of about 273,000 patients showed a 1% increase in the percentage of breast, lung, and colorectal cancers diagnosed at the earliest, most treatable stage between 2013 and 2014. This small percentage represents a significant number of new cases and could potentially lead to improved outcomes.

Lead author Huesong Han, PhD, Strategic Director of Health Policy and Healthcare Delivery Research at the American Cancer Society, said: "Although we only analyzed data from a limited timeframe, the fact that there appears to be a positive trend in diagnosis at an earlier stage in these common cancers is encouraging."

The percentage of patients diagnosed with prostate cancer at earlier stages did not increase, and the authors attributed this to the USPSTF recommendation against routine PSA screening in the general population.

by Adrian Barfield

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