The detective: Q&A with Peter Gibbs

How did you become interested in medical research?
I’ve always had an interest in science and, particularly, medicine. Growing up on a farm, I was able to observe the entire circle of life. My mother was a nurse, and through conversations with her as a youngster I had exposure to hospitals and what happens in them. One of the things that always impressed me was the way my mother spoke about doctors and the respect she had for them. But the most important reason was and continues to be my passion to help people and prevent needless suffering.

How important were the places you trained as a young scientist?
It’s not the places but the people you train with that are most important. The people I worked with not only inspired me and showed me how to do the research basics, including planning projects and writing grants and papers, but also encouraged me along my scientific journey. They gave me invaluable guidance when times were difficult and helped me work out where I wanted to go and to identify what I wanted to do in the future.

Can you give an example?
Bill Robinson was a visiting professor from Denver whose interest in melanoma sparked my initial interest in that disease. He was an inspirational person and had a passion for research that I carry with me to this day. Bill was also a true mentor and a wise counselor. I learned a lot just by observing him and how he interacted with people.

You pioneered a cancer treatment called SIRT, which was hailed a global lifesaver. Can you explain what it is and why it was so effective?
SIRT is an interesting therapy. It was originally developed in Melbourne, Australia, and I got involved with it early on. It’s a one-off treatment where tiny radioactive beads, about one-third the width of a human hair, are injected directly into the liver via a catheter inserted into an artery near the groin. The beads lodge in the liver and release a radiation dose over a number of days to shrink the tumors. The effect is confined to the liver so adjoining tissues are not damaged. It’s a local form of radiation treatment that can be safely combined with chemotherapy, and the two together are potentially quite a powerful combination. We’re finishing up an international phase 3 clinical trial and the results will be reported mid next year. This study is particularly relevant to the hundreds of thousands of people worldwide who develop liver metastases each year, who need treatments that more effectively target these liver tumors.

Can you tell us a little bit about your collaboration with Ludwig Johns Hopkins and the impact your joint efforts have had on cancer detection and prevention?
It’s a terrific collaboration and the most exciting thing I’m doing at the moment. The development of noninvasive methods to detect and monitor tumors continues to be a major challenge in oncology, and together we’re exploring the utility of circulating tumor DNA as noninvasive cancer biomarkers for colorectal cancer screening and treatment. This has great potential as a more effective and patient-friendly method for the detection, monitoring and treatment of colorectal cancer, and indeed most types of cancer. Together it’s a great partnership, which I believe is going to start having a big impact on patients in the near future.

This all began when I was visiting Baltimore in 2010, when Bert presented his initial data around circulating DNA in patients undergoing liver resection. I felt it showed enormous promise for helping people with colorectal cancer from early-stage right through to end-stage disease. That stimulated the initial conversation, and collaboration was a natural next step.
We started with one protocol, generously supported by Ludwig, and have been able to leverage that initial investment with funding from a wide range of sources, such that we now have seven colorectal studies up and running, covering the spectrum from screening right through to optimizing care of people with advanced cancer. We’ve also begun work in pancreatic cancer. For each of the studies in Melbourne, we’re collecting the data and the samples and sending them over to Bert’s lab for analysis; then we work together to understand the results. They have been fantastic collaborators.

Besides the time difference, what are the challenges in collaborating with other Ludwig researchers?
The biggest challenge is the distance. Teleconferencing and videoconferencing are viable options, but it would be great to be able to meet more frequently, particularly face-to-face, and spend more time together looking at the data. But our trips to the US are frequent enough and the work continues to move forward, with lots of e-mails back and forth.

How soon before blood tests become routine and we are able to detect early signs cancer?
That’s a very difficult question to answer. The initial data we have are very promising and I would expect in the next five years that measuring circulating DNA will become a standard part of managing patients with early-stage through late-stage colorectal cancer. Most exciting for me is the possibility, within the next ten years, that patients will be given a routine blood test to screen for cancer as part of their annual physical. It would be a real breakthrough because the data so far indicate that if a doctor can detect an abnormality in the bloodstream it means there’s a very high chance of that person having an early cancer hiding somewhere. It’s a safe, noninvasive and very promising initial screen to detect cancer in someone who wouldn’t otherwise have any symptoms. A blood-based test could be transformative in how we screen patients for colorectal cancer and potentially many other cancer types where early diagnosis is critical; it would save lives and result in major savings of health care dollars.

How effective is screening for colorectal cancer?
Very, with recent data indicating that the rate of colorectal cancer in the US has declined 30% on the basis of screening. Colonoscopies are the ‘gold standard’ for colorectal cancer screening. They can detect the disease at an early stage when it’s most curable—and even prevent it by finding polyps before they become cancerous. In the US, uptake of screening is pretty good: Roughly more than half of all Americans older than 50 are getting screened. In Australia it’s terrible, with only 5% or 10% of the eligible population being screened. There are lots of factors at play, but I think patients often resist or delay having colonoscopies because of the preparation, discomfort or fear of pain. Or maybe it’s just the yuck factor.

How important is the ‘celebrity factor’ in increasing awareness of screening?
In the US, screening jumped dramatically when Katie Couric had a colonoscopy on air on the “Today” show in 2002. So the celebrity factor is definitely a big driver in promoting awareness of a disease. In Australia there aren’t any celebrities who’ve come out and said they’ve had colorectal cancer. Entertainers like Olivia Newton-John and Kylie Minogue had breast cancer and were very open about coming forward and promoting mammograms and screenings, which stimulated interest in these preventive measures. But the few celebrities I’ve come across with colorectal cancer are very reluctant to mention it in public, and the media report it as abdominal or stomach cancer—never bowel cancer.

Colorectal cancer incidence rates have declined, but why haven’t survival rates?
In the US the number of colorectal cancer deaths is declining, which is great news, but elsewhere in the world it’s actually increasing. And in parts of Asia it’s increasing dramatically. In places where it used to be number five or six in terms of cancer incidence, it’s now number one. These countries have adopted some of the bad bits of the West—sedentary lifestyle, poor food choices, smoking—and it’s showing up as a spike for colorectal cancer more than any other tumor type. To make matters worse, many of these countries don’t have any screening programs, so many patients are being diagnosed very late.

In difficult times, what motivated you to continue with your research?
The number one driver is the potential impact on patients. That’s something I’ve always been very focused on. Through the work we’re doing with circulating tumor DNA and screening, we can make a huge difference by diagnosing cancers earlier and stopping people from dying of cancer rather than focusing on keeping someone with advanced cancer alive a little bit longer. Some of the work we’re doing is getting to the point of presentation and publication, and I think it was quite exciting at the American Society of Clinical Oncology meeting this year when the stage 2 circulating tumor DNA data was presented for the first time.

How do you balance your commitments to work and family?
Conflicts are ongoing because the work you’re doing is never finished. There’re always things that need to get done. Deadlines never disappear. You get past one and then another one comes up. You always have this false sense that maybe you’ll get past this crisis or this hurdle and free time will open up, but inevitably it doesn’t. You have to plan and make time for the things that are important—especially family—as you go along and not just wait for opportunities to come up.

What would you like to accomplish in the future?
Early diagnosis and treatment are crucial in fighting cancer. Once cancers show clinical symptoms, it’s often too late. The earlier we get them, the better the chances of recovery. Current screening methods can detect cancers at a very early stage and save thousands of lives each year. They can be the difference between life and death, particularly with bowel cancer. I’d like to develop a new screening test to detect cancer with a far greater impact. That really would be a major breakthrough in cancer diagnostics.

You’re the lead investigator on the ASPREE study. Can you explain what this is and what you expect it to accomplish?
Aspirin in Reducing Events in the Elderly (ASPREE) is a five-year international randomized clinical trial designed to determine whether the benefits of aspirin outweigh the risks in healthy people aged 70 and older. Early data suggest that aspirin can markedly reduce the risk of many cancers, including colorectal cancer, by 30 to 40%. There are lots of other reasons to take aspirin: it can reduce the risk of heart attack, stroke, dementia and other diseases of aging. But the big question has always been what’s the risk-benefit ratio, as aspirin can cause bleeding in the stomach as well as bleeding in the brain, which can cause a stroke. Initial results of the study will be available in 2018, and I’m hoping we can definitively see a reduction in the risk of colorectal cancer and multiple cancers as well, potentially opening up aspirin as a routine preventive medication.

If aspirin is really a wonder drug, shouldn’t we all be taking it every day to ward off potential illnesses?
You have to remember that aspirin is a drug and with any drug there are side effects. In recent years, there’ve been a number of studies showing that over the long term it can reduce the risk of cancer, but the mechanisms by which it does this are still unclear. We know inflammation plays an underlying role in cancer development and aspirin helps reduce inflammation. Other research has shown that aspirin’s ability to reduce blood clotting could play a role in its cancer-fighting abilities. I think many of these questions will be answered in the next decade or so as the results of multiple ongoing clinical trials become available.

Who or what would inspire you if you were 21 again?
People. People who’ve achieved great things. People who’ve done it in a way that I admire. People who’ve been collaborative. People who’ve shared and worked as a team. They’re the ones who inspire me much more than individuals who’ve done it by themselves. People who work in areas that many others think don’t show much promise for success, but with persistence and ongoing self-belief, over time they achieve great things and have a fantastic story to share. That’s inspirational. It’s those stories of success and the impact of those research stories that motivate and inspire the younger generation to take a bold path and start something new and potentially turn it into something that makes a difference.

As you get older, one of the sadder things is that there aren’t as many people above you to inspire and guide you, to offer you help and advice. You’re increasingly on your own. Tony Burgess, someone I greatly respect and admire, is still a source of wise counsel, and it’s very helpful to have people like him around to act as a sounding board to bounce ideas off. It’s essential to have those types of people around you to mentor you, even if they don’t have an in-depth understanding of the issues. Being able to seek their advice and help at times when you’re not quite sure what to do is invaluable.

Is there anything else that you’d like to share?
Ludwig’s support and connections have given me the freedom to pursue unique opportunities and conduct my research without deadlines or the need for immediate results. Many of my colleagues don’t have this luxury. Unlike industry and other organizations, Ludwig isn’t looking for short-term gains: they encourage all of their researchers to step back and ask how they can make the biggest impact.