No Shortage of Important Results

Here are two from the past week – a risk prediction model presented at the 2024 ASCO Quality Care Symposium that may help us improve the care we can provide for patients with advanced cancer, and results of the S1011 surgical trial in bladder cancer just published in the New England Journal of Medicine.

Which patients are at higher risk of acute care use?
Development of the risk prediction model was driven by the fact that patients with advanced cancer enrolled to our clinical trials are at high risk for needing acute care. In the data analyzed for this model, slightly more than two-thirds (67.5 percent) of patients had experienced at least one emergency room (ER) visit or unplanned hospital stay in their first year after trial enrollment. 

Identifying which of these patients are at greatest risk could let us better target early interventions that might reduce their need for acute care, improving care quality while reducing costs. Reducing unplanned hospitalizations and ER visits for these patients can also reduce interruptions in their cancer treatment.

A SWOG team led by Drs. Dawn Hershman and Joseph Unger, working from SWOG trial data and Medicare claims data, formulated and validated a risk model that can help us predict which patients are at highest risk.

The team started with data from six SWOG trials (two in prostate cancer, three in lung cancer, and one in pancreatic cancer). To determine which participants on these trials required acute care, they linked patient data to Medicare claims data to identify emergency room visits and hospital stays.

This gave them linked information on 1,397 trial participants, and they split their overall sample 60/40 into a training data set and a test data set that they could use to validate the model they would develop.

In building that model, they initially assessed 23 baseline factors, including certain patient comorbidities, information generally not tracked in the trial data but available through the linked Medicare records. 

The risk model they ultimately derived from the training data incorporates four risk factors – performance status score (0 vs 1+), and the presence or absence of coronary artery disease, hypertension, or liver disease. 

For patients in the training data set, having two or more of these risk factors more than tripled their risk of using acute care as compared to patients who had one or zero risk factors.

The team found that applying their risk prediction model to the test data set generated consistent results, confirming the model’s validity.

It’s important to note that three of the four risk factors identified in the model are comorbid conditions. Given this, the research team rightly points out that, as we broaden trial eligibility criteria to include more patients with comorbidities, we may also need to anticipate a higher risk of acute care use among enrolled patients and may need to target interventions accordingly.

S1011: Standard lymphadenectomy, standard practice
The second set of findings I’ll discuss with you are the primary results for SWOG study S1011 (just out in NEJM), which answer a key surgical question related to the treatment of patients with localized muscle-invasive bladder cancer. 

When these patients undergo surgery to have their cancerous bladder removed, the surgeon will also remove a number of lymph nodes, as a bilateral pelvic lymphadenectomy is associated with improved outcomes for these patients.

Based on some evidence that removing more nodes might be even more effective, an extended lymphadenectomy, with nodes also removed above the pelvic cavity, has become standard procedure at many institutions, though whether there is a clear oncologic benefit to this compared to the standard lymphadenectomy has been an open surgical question.

The SWOG S1011 study, led by Dr. Seth Lerner, chair of our genitourinary committee, set out to provide a definitive answer. Surgeons participating in the study randomized 592 eligible patients to either standard or extended lymphadenectomy. 

With a median follow-up of more than six years, the data show no significant difference in disease-free or overall survival between the two arms. But they do reveal a higher rate of grade 3-4 adverse events among patients on the extended lymphadenectomy arm, and an increased risk of death in the 90 days following surgery.

So, the answer to the surgical question of standard versus extended seems to be that bilateral standard lymphadenectomy should be standard practice.

I’ve said it before but it bears repeating: S1011 is the type of trial that could only have been carried out in the NCI National Clinical Trials Network (NCTN). The necessity for public funding, the sheer scale required (36 surgeons contributing at 27 institutions), the need for rigorous credentialing of participating surgeons, and the Is less more? nature of the trial question – all pure NCTN. 

An answer to a key question that will improve surgical care for patients with bladder cancer. A risk model that could help us keep patients with advanced cancer out of the ER.

The important SWOG research results keep coming in. As long as they do, I’ll keep sharing them with you!