Cancer prevention: are drugs the key?
Saturday morning kicked off with a session on breast cancer chemoprevention – the prophylactic use of antiestrogen therapies in women at high risk of breast cancer – where Katherine Crew outlined the risks and benefits. Crew described the results of the IBIS 1 study, showing that taking tamoxifen is associated with reduced breast cancer incidence over a median 16-year follow-up.
You can read more about the IBIS 1 study in a commentary published in BMC Medicine as part of our Spotlight on breast cancer collection, where Victor Vogel recommends that breast cancer chemoprevention agents should be used more in clinical practice.
At ASCO, Crew described a new decision aid designed to increase uptake of breast cancer chemoprevention, which aims to help physicians and patients weigh up the risks and benefits. A clinical trial is currently underway to test whether this tool is effective in increasing chemoprevention, and we look forward to seeing the results in the next couple of years!
Emerging data suggest that the prophylactic use of drugs could also play a role in the prevention of colorectal cancer (CRC). Simer Bains presented the results of a study analyzing data from 25,000 patients in the Norwegian Cancer Registry, showing that aspirin is associated with improved survival in CRC patients. Kimmie Ng outlined data suggesting that vitamin D is associated with improved survival in CRC, and described ongoing randomized controlled trials assessing whether vitamin D supplementation can improve outcome.
Focusing on prostate cancer, Noel Clarke discussed results presented in a poster by Grace L. Lu-Yao and colleagues, showing that statin and metformin use is associated with reduced disease-specific mortality. Clarke explained that prospective studies are underway to further entangle these associations, and ascertain whether these drugs have a true effect on prostate cancer outcome.
The promise of immunotherapy
Sunday’s plenary session saw the presentation of some intriguing new findings on the use of immunotherapy to treat melanoma. Jim Allison highlighted the immense potential of immune checkpoint blockade against cancer, explaining that:
“the promise of immunotherapy is not an improvement in survival by a few months, but by a few decades”
the promise of immunotherapy is not an improvement in survival by a few months, but by a few decades
Jim Allison, ASCO 2015
Jedd Wolchok presented results from the CheckMate 067 study showing that nivolumab alone or combined with ipilimumab is associated with longer progression-free survival than ipilimumab alone in patients with advanced melanoma. The combination of both drugs led to a reduction in tumor size in 58% of patients. Discussing these findings, Michael Atkins emphasized that:
“Ipilimumab alone can no longer be considered first line immunotherapy for patients with advanced melanoma”
Looking to the future, Atkins explained that better biomarkers to predict those likely to respond to combination immunotherapy are needed.
In addition to its beneficial effects in melanoma, new clinical trial data presented at ASCO highlight the potential of nivolumab for treating lung cancer. A landmark phase 3 study presented by Luis Paz-Ares showed that the drug more than doubles overall survival in patients with non-small cell lung cancer. Paz-Ares stated that:
“nivolumab could potentially become a new standard therapy for patients with previously treated NSCLC”
Molecular profiling and precision medicine: are we there yet?
As our knowledge of the molecular alterations underlying cancer development increases, clinical trials of agents targeting these changes are beginning to be developed. Martine Piccart-Gebhart described a number of such trials that are currently underway, advising that molecular-guided trials must be flexible in design, and should be conducted across a number of centers to ensure large patient numbers and multiple target biomarkers.
poor interpretation of genomic data can be deleterious to patient care
Fabrice André, ASCO 2015
Fabrice André explained that testing for markers including AKT1, ERBB2 and PIK3CA can be useful in the context of clinical trials, but cautioned that poor interpretation of genomic data can be deleterious to patient care.
The utility of next-generation sequencing (NGS) and tumor molecular profiling in the oncology clinic is debated in a forum article published in BMC Medicine, where Kimberly Blackwell highlights the clinical potential of NGS, whereas Mark Robson cautions that it is not yet ready for routine clinical use.
New clinical trials in breast cancer
The eagerly-awaited results of a number of clinical trials in breast cancer were presented on Monday morning at ASCO. Nicholas Turner shared findings from the PALOMA-3 trial, showing that palbociclib more than doubles progression-free survival in patients with hormone receptor positive, HER2-negative breast cancer.
Nadia Harbeck described interim analyses demonstrating improved pathologic complete response with the antibody-drug conjugate T-DM1. However, in the MARIANNE study presented by Paul Ellis, T-DM1 was not associated with improved survival when compared with trastuzumab plus taxane treatment for HER2-positive metastatic disease. Discussing these results, Shanu Modi concluded that T-DM1 is unlikely to show a survival benefit in future clinical trials, but has a favorable toxicity profile compared with other regimens.
These are just some of the exciting new findings presented at ASCO. We look forward to seeing how the results of the clinical trials presented over the last few days are incorporated into clinical decision making in the coming months.
As well as publishing articles across all fields of cancer research, BMC Medicine currently has two special article collections accepting submissions in clinical oncology. Our breast cancer series, guest edited by Debu Tripathy, contains review and comment on new and controversial topics, and is now open for research submissions. Spotlight on prostate cancer, guest edited by Sigrid Carlsson and Andrew Vickers, is a new article collection open for research submissions in all areas of prostate cancer research and treatment. If you have any research you would like us to consider for inclusion in either collection, please email email@example.com.
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