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Wang X, Gu L, Zhang Y, Sargent DJ, Richards W, Ganti AK, Crawford J, Cohen HJ, Stinchcombe T, Vokes E, Pang H. Validation of survival prognostic models for non-small-cell lung cancer in stage- and age-specific groups. Lung Cancer 2015; 90:281-7. [PMID: 26319317 DOI: 10.1016/j.lungcan.2015.08.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 07/03/2015] [Accepted: 08/13/2015] [Indexed: 01/16/2023]
Abstract
PURPOSE Prognostic models have been proposed to predict survival for non-small-cell lung cancer (NSCLC). It is important to evaluate whether these models perform better than performance status (PS) alone in stage- and age-specific subgroups. PATIENTS AND METHODS The validation cohort included 2060 stage I and 1611 stage IV NSCLC patients from 23CALGB studies. For stage I, Blanchon (B), Chansky (C) and Gail (G) models were evaluated along with the PS only model. For stage IV, Blanchon (B) and Mandrekar (M) models were compared with the PS only model. The c-index was used to assess the concordance between survival and risk scores. The c-index difference (c-difference) and the integrated discrimination improvement (IDI) were used to determine the improvement of these models over the PS only model. RESULTS For stage I, B and PS have better survival separation. The c-index for B, PS, C and G are 0.61, 0.58, 0.57 and 0.52, respectively, and B performs significantly better than PS with c-difference=0.034. For stage IV, B, M and PS have c-index 0.61, 0.64 and 0.60, respectively; B and M perform significantly better than PS with c-difference=0.015 and 0.033, respectively. CONCLUSION Although some prognostic models have better concordance with survival than the PS only model, the absolute improvement is small. More accurate prognostic models should be developed; the inclusion of tumor genetic variants may improve prognostic models.
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Affiliation(s)
- Xiaofei Wang
- Department of Biostatistics & Bioinformatics and Alliance Statistics and Data Center, Duke University, Durham, NC, United States.
| | - Lin Gu
- Department of Biostatistics & Bioinformatics and Alliance Statistics and Data Center, Duke University, Durham, NC, United States
| | - Ying Zhang
- Department of Biostatistics & Bioinformatics and Alliance Statistics and Data Center, Duke University, Durham, NC, United States
| | - Daniel J Sargent
- Alliance Statistics and Data Center, Mayo Clinic, Rochester, MN, United States
| | | | - Apar Kishor Ganti
- Department of Internal Medicine, VA Nebraska Western Iowa Health Care System and University of Nebraska Medical Center, Lincoln, NE, United States
| | - Jeffery Crawford
- Department of Medicine, Duke University Medical Center, Durham, NC, United States
| | - Harvey Jay Cohen
- Department of Medicine, Duke University Medical Center, Durham, NC, United States
| | - Thomas Stinchcombe
- Department of Medicine, University of North Carolina, Chapel Hill, NC, United States
| | - Everett Vokes
- Department of Medicine, University of Chicago, Chicago, IL, United States
| | - Herbert Pang
- Department of Biostatistics & Bioinformatics and Alliance Statistics and Data Center, Duke University, Durham, NC, United States; School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
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Abstract
In cancer research, it is important to evaluate the performance of a biomarker (e.g., molecular, genetic, or imaging) that correlates patients' prognosis or predicts patients' response to treatment in a large prospective study. Due to overall budget constraint and high cost associated with bioassays, investigators often have to select a subset from all registered patients for biomarker assessment. To detect a potentially moderate association between the biomarker and the outcome, investigators need to decide how to select the subset of a fixed size such that the study efficiency can be enhanced. We show that, instead of drawing a simple random sample from the study cohort, greater efficiency can be achieved by allowing the selection probability to depend on the outcome and an auxiliary variable; we refer to such a sampling scheme as outcome and auxiliary-dependent subsampling (OADS). This article is motivated by the need to analyze data from a lung cancer biomarker study that adopts the OADS design to assess epidermal growth factor receptor (EGFR) mutations as a predictive biomarker for whether a subject responds to a greater extent to EGFR inhibitor drugs. We propose an estimated maximum-likelihood method that accommodates the OADS design and utilizes all observed information, especially those contained in the likelihood score of EGFR mutations (an auxiliary variable of EGFR mutations) that is available to all patients. We derive the asymptotic properties of the proposed estimator and evaluate its finite sample properties via simulation. We illustrate the proposed method with a data example.
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Affiliation(s)
- Xiaofei Wang
- Department of Biostatistics and Bioinformatics, Duke University Medical Center, DUMC 2721, Durham, North Carolina 27710, USA.
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Le Péchoux C, Ferreira I, Bruna A, Roberti E, Besse B, Bretel JJ. Cancers bronchiques : la radiothérapie prophylactique des aires ganglionnaires a-t-elle encore une place ? Cancer Radiother 2006; 10:354-60. [PMID: 17035060 DOI: 10.1016/j.canrad.2006.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The use of conformal radiotherapy in lung cancer has considerably evolved with the advent of improved staging technologies and methods of radiation delivery. Patients with limited disease, inoperable for medical reasons, may be treated with conformal radiotherapy alone; patients with more advanced disease are treated with combined chemo-radiotherapy. If local control may be improved by radiotherapy dose escalation according to several studies, toxicity and more particularly pulmonary toxicity seems to be related to radiation volume. Thus the use of elective nodal irradiation is being questioned. Data for early stage (stage I) non-small-cell lung cancer treated with conformal radiotherapy or stereotactic hypofractionated radiotherapy strongly supports the use of smaller fields that do not incorporate elective nodal regions; local control and survival rates approach those of surgical series. In locally advanced non-small cell lung cancer, eliminating elective nodal irradiation allows to maximize tumor dose and minimize normal tissue toxicity in combined modality treatments; results are encouraging. The use of staging modalities such as positron emission tomography and eventually oesophageal ultrasonography is increasing, allowing to encompass the tumor volume with more accuracy. Several studies have confirmed that involved-field irradiation results into a regional nodal rate of less than 10%. Further larger-scale studies would be needed to definitely establish "no elective nodal irradiation" as a standard in non-small cell lung cancer. There are very few data concerning small cell lung cancer.
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Affiliation(s)
- C Le Péchoux
- Département de Radiothérapie, Institut Gustave-Roussy, 39, Rue Camille-Desmoulins, Villejuif, France.
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