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J Thorac Oncol. 2008 Apr;3(4):422-6. doi: 10.1097/JTO.0b013e318167146b.

Variation in experts' beliefs about lung cancer growth, progression, and prognosis.

Author information

1
Center for Primary Care and Outcomes Research (PCOR), 117 Encina Commons, Stanford, CA 94305, USA. emschultz@stanford.edu

Abstract

INTRODUCTION:

Little is known about the natural history of malignant solitary pulmonary nodules (SPN). Experts' beliefs may help fill these knowledge gaps and explain variation in clinical practices.

METHODS:

Using a modified Delphi process, we surveyed a group of lung cancer experts about tumor growth, disease progression, and prognosis in patients with malignant SPN. After completing the first survey, experts were given the opportunity during a second survey to revise their responses in light of their peers' beliefs.

RESULTS:

The response rate was 100% (14 of 14) for both surveys. There was consensus that disease progression depends on the tumor growth rate, that survival for patients with untreated lung cancer is approximated by a declining exponential function, and that treatment is delayed by approximately 1 tumor volume doubling time (TVDT) in patients who undergo a period of "watchful waiting." Just over half of experts (8 of 14) agreed that lung cancer progresses in three steps (from local to regional to distant disease), whereas 43% (6 of 14) preferred a 2-step model (from local to systemic disease). Likewise, 64% of experts (9 of 14) believed that malignant nodules grow exponentially, whereas 36% (5 of 14) believed that growth is slower than exponential. Experts' estimates of the risk of disease progression during a period of observation lasting 1 TVDT varied from 1 to 50%. Estimates of 5-year survival for patients in whom diagnosis and treatment were delayed by 1 TVDT varied between 40% and 80%.

CONCLUSIONS:

There is substantial variability in experts' beliefs about the natural history of untreated, malignant SPN. Different beliefs may be partly responsible for variation in management practices.

PMID:
18379363
PMCID:
PMC2903546
DOI:
10.1097/JTO.0b013e318167146b
[Indexed for MEDLINE]
Free PMC Article

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