Current or Prior Cancers Affect PCI Outcomes Differently, Large Analysis Shows

Cancer’s influence on PCI outcomes hinges on the type and stage of the malignancy, new data suggest. Clinicians considering revascularization in patients with a current or prior diagnosis of cancer should therefore tailor care to account for these differences, researchers say.

“For example, colon cancer is associated with the greatest risk of bleeding complications, whereas patients with lung cancer are at the greatest risk of mortality, whilst patents with a current breast cancer do not appear to have an increased mortality risk,” senior author Mamas A. Mamas, BMBCh, DPhil (Keele University, Stoke-on-Trent, England), told TCTMD via email. “Previous to this work, we used to treat patients with a one-size-fits-all approach, whereas now we can understand that the type of complications and outcomes associated with different cancers are very different.”

Mamas added that interventional cardiologists are increasingly encountering patients with either current or historical cancer, fueling the need for this type of data.

“From the interventional cardiological space, patients with active cancer are at increased risk of bleeding complications and whilst elective procedures can be deferred, those patients admitted with ACS cannot,” he said. “This often leads to challenges to the treating physicians as [dual antiplatelet therapy (DAPT)] may delay cancer surgery or place these patients at increased risk of bleeding events.” Cancer-specific registries are needed to better understand longer-term outcomes in patients with both cancer and cardiovascular disease, Mamas stressed.

[W]e used to treat patients with a one-size-fits-all approach, whereas now we can understand that the type of complications and outcomes associated with different cancers are very different. Mamas A. Mamas

In an interview with TCTMD, Daniel Lenihan, MD (Washington University School of Medicine in St. Louis, MO), who was not involved in the study, said data on patients with both cancer and cardiovascular disease are greatly needed because such patients are almost always excluded from clinical trials and registries by researchers seeking to make their study populations as "clean" as possible.

"If we could identify a subset of patients that benefited from an invasive evaluation and ultimate treatment, and who did particularly well, that would give you important practice suggestions," Lenihan noted.

Lung Cancer More Than Doubles Post-PCI Mortality

Published online November 30, 2018, ahead of print in the European Heart Journal, the study used data from the Nationwide Inpatient Sample to shed light on the association between cancer diagnosis and in-hospital mortality and complications in more than 6.5 million PCI procedures performed in the United States from 2004 to 2014.

Among the 6,571,034 PCI procedures included in the study, rates of current and previous cancer were 1.8% and 5.8%, respectively. Mamas and colleagues, led by Jessica E. Potts, MSc (Keele University, Stoke-on-Trent), focused on prostate, breast, colon, and lung cancer.

Overall, patients with a current cancer diagnosis had higher in-hospital mortality and worse outcomes after their procedures than those with a historical cancer. The group with current lung cancer had the poorest outcomes of all cancer types, with greater risks of in-hospital mortality (OR 2.81; 95% CI 2.37-3.34) and any in-hospital complication (OR 1.21; 95% CI 1.10-1.36) than patients with no prior history of cancer. Having a current diagnosis of colon cancer was independently associated with greater risks of any complication (OR 2.17; 95% CI 1.90-2.48) and bleeding (OR 3.65; 95% CI 3.07-4.35), but not with mortality (OR 1.39; 95% CI 0.99-1.95). Current prostate cancer was associated with increased bleeding risk (OR 1.41; 95% CI 1.20-1.65), while current breast cancer was not linked to worse outcomes compared with not having cancer.

The study also found that patients with a metastatic cancer of any kind had the poorest prognosis of any cancer group, with a higher risk of mortality and complications, including major bleeding events. Patients with metastatic colon cancer had the highest rate of major bleeding among this subgroup, with nearly a fivefold increase, while metastatic lung cancer was associated with a nearly fourfold increase in the risk of in-hospital death.

‘Longtime Smokers’ Especially at Risk

Among patients with an earlier diagnosis of cancer, though, only lung cancer was linked to increased death and complications after taking into account baseline differences.

While not surprising, that finding is an important one to document in PCI patients, Lenihan emphasized to TCTMD.

“The overwhelming majority of those patients are going to be longtime smokers. They’re going to have preexisting lung disease and preexisting coronary disease,” he commented. “They may not have known about it [but] they've already got significant vascular disease, for the most part, and a diagnosis of lung cancer, so they're going to be particularly high-risk patients.” Awareness of this, he added, should spur very careful evaluation of these patients and consideration of medical therapy over PCI as needed.

Conversely, the relatively good outcomes of the breast cancer patients, Lenihan said, are likely related to the fact that women with past or current breast cancer tend to be in better overall health, younger, and less likely to have serious comorbid conditions that complicate decisions about PCI compared with other cancer groups.

As to how the data might help influence operator decisions in cancer patients, Mamas said it could spur the use of stent platforms such as BioFreedom (Biosensors) that only require abbreviated DAPT in cancer subtypes with high bleeding risk, or inspire shortened DAPT duration. Importantly, he said the results can also help “identify those patients where radial access particularly should be adopted.”

Working alongside oncologists to improve care for these patients is another message he said he hopes interventional cardiologists will take away from the paper.

“Many patients do not have PCI because of the belief that they are much higher risk than they actually are, or [they] have procedures without thought of potential sequelae or without steps taken to avoid these,” Mamas explained. “Early discussions with oncology teams will very much help individualize the care of such patients and ensure that patients are not declined PCI inappropriately because of perceived risks and when PCI procedures are undertaken, that they are undertaken in a manner that takes into account potential complications with the necessary precautions [in place].”