Web App May Help Estimate Survival Impact of Delayed Cancer Treatment

By Marilynn Larkin

November 05, 2020

NEW YORK (Reuters Health) - An online decision-making app could help clinicians estimate the impact of pandemic-induced delayed cancer treatment on individual patients, helping to prioritize those most at risk of death, a modeling study suggests.

The app "provides real time and individualized quantification of the risks associated with delaying cancer treatment during the COVID pandemic," Dr. Matthew Schipper of the University of Michigan, Ann Arbor, told Reuters Health by email. "It is ready to be used by clinicians and others involved in these decisions."

The app, OncCOVID, is available at http://onccovid.med.umich.edu/.

As reported in JAMA Oncology, age-specific and cancer stage-specific estimates of overall survival pre-COVID-19 were extracted from the SEER database for close to seven million individuals with 25 cancer types who received cancer diagnoses in 2005 to 2006.

Data from more than five million individuals in the National Cancer Database were used to estimate the independent impact of treatment delay by cancer type and stage. In addition, data from 275 patients, collected from mid-March to mid-May, were used in a nested case-control study to estimate the COVID-19 mortality rate by age and number of comorbidities.

Substantial heterogeneity was seen with respect to the association between delayed cancer treatment and net survival among patients with a given cancer type and stage; these two variables were not sufficient to discriminate the net impact of immediate versus delayed treatment.

By contrast, at the time of the study, the OncCOVID web application allowed for the selection of up to 47 inputs, 18 covariates (e.g., age and comorbidities), and 29 parameter estimates to characterize individual risk estimates for those receiving immediate versus delayed cancer treatment.

Overall, individualized survival estimates were associated with patient age, number of comorbidities, treatment received, and specific local community estimates of COVID-19 risk.

For example, a 70-year-old woman from New York City (during the peak of the first wave of the pandemic) had a diagnosis of stage II triple-negative breast cancer - for which a standard of care option is breast conservation surgery, chemotherapy, and adjuvant radiotherapy - as well as hypertension and diabetes. Given the consequences to her of acquiring COVID-19 while seeking treatment, OncCOVID estimated that compared with a three-month delay, immediate treatment was associated with an 8% worse five-year overall survival or a five-year restricted mean survival time decrease of 165 days.

By contrast, a 40-year-old patient with no comorbidities and the same stage II breast cancer diagnosis living in Washtenaw County, Michigan, would have a less than 0.1% estimated difference in five-year overall survival between immediate and delayed treatment.

Dr. Schipper said, "We are working on updating the models used by the app including, for example, incorporating more recent data on COVID mortality risk in cancer patients. We are also working on methods to provide uncertainty estimates for the predictions, as the uncertainty can be large, particularly when looking several months in the future."

Dr. Brian Rini of the Vanderbilt-Ingram Cancer Center in Nashville, coauthor of a related editorial, commented in an email to Reuters Health, "Developing tools to help clinicians and patients estimate the benefit/risk of cancer therapy versus COVID risks is critical at present. This is a rapidly-changing environment that will require updated data to make the most informed decision."

On a population level, however, the authors of a systematic review and meta-analysis in The BMJ found that a four-week delay in treatment is associated with an increase in mortality across all common forms of cancer treatment, and that longer delays are increasingly detrimental.

The literature search by Dr. Timothy Hanna of Queen's University in Kingston, Ontario and colleagues yielded 34 eligible studies for 17 indications in seven major cancer types (bladder, breast, colon, rectum, lung, cervix, and head and neck) involving more than 1.2 million patients undergoing surgery, systemic treatment, and/or radiotherapy.

The association between treatment delay and increased mortality was significant for 13 of the indications. However, the authors note, their results "reflect the impact of delay on large and expectedly heterogeneous populations with varying risks of recurrence."

"Therefore," they suggest, "these estimates are best used at a policy and planning level for modeling, rather than for individual risk prediction."

SOURCES:

https://bit.ly/3eCLKJH and https://bit.ly/3oUHZnn JAMA Oncology, online October 29, 2020.

https://bit.ly/38jsPlE BMJ, online November 4, 2020

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