Metastasis dynamics for non-small-cell lung cancer: effect of patient and tumor-related factors.

BACKGROUND: We studied event dynamics (probability of an event occurring over a specific time interval) in patients undergoing surgery for early-stage non-small-cell lung cancer (NSCLC) according to patient and tumor characteristics. METHODS: By using a database of 1506 patients who underwent initial surgery for NSCLC, event dynamics, based on a time-specific hazard rate, were evaluated. The event of interest was the development of distant metastases, with or without a local recurrence. The effect of sex, tumor size, nodal involvement, histology, lymphovascular space invasion, pleural invasion, age, and race were studied. RESULTS: The hazard rate for developing distant metastases was not constant over time but was characterized by specific peaks, the first being approximately 9 months after surgery and the second at 18 to 20 months for men and 24 to 26 months for women. For women, the hazard rate peaked considerably in the first year. For men, the hazard rate peaks were smaller but lasted for a longer duration. Pathologic factors associated with a higher risk of recurrence (eg, size, lymph node involvement, pleural invasion) all increased the sex-specific hazard rates. CONCLUSIONS: The probability of developing distant metastases after surgery for NSCLC peaks at specific and consistent time intervals after surgery, with specific differences between men and women. A factor-specific modulation of peak heights that ranged from no impact (eg, race) to relevant effects for primary tumor size, nodal involvement, and pleural invasion, possibly related to sex, was also observed. The bimodal distant metastases dynamics may be an intrinsic feature of metastatic progression in NSCLC.

Lymphovascular invasion in non-small-cell lung cancer: implications for staging and adjuvant therapy.

BACKGROUND: Lymphovascular space invasion (LVI) is an established negative prognostic factor and an indication for postoperative radiation therapy in many malignancies. The purpose of this study was to evaluate LVI in patients with early-stage non-small-cell lung cancer, undergoing surgical resection. METHODS: All patients who underwent initial surgery for pT1-3N0-2 non-small-cell lung cancer at Duke University Medical Center from 1995 to 2008 were identified. A multivariate ordinal regression was used to assess the relationship between LVI and pathologic hilar and/or mediastinal lymph node (LN) involvement. A multivariate Cox regression analysis was used to evaluate the relationship of LVI and other clinical and pathologic factors on local failure (LF), freedom from distant metastasis (FFDM), and overall survival (OS). Kaplan-Meier methods were used to generate estimates of LF, FFDM, and OS in patients with and without LVI. RESULTS: One thousand five hundred and fifty-nine patients were identified. LVI was independently associated with the presence of regional LN involvement (p < 0.001) along with lobar (versus sublobar) resections (p < 0.001), and an open thoracotomy (versus video-assisted thoracoscopic surgery). LVI was not independently associated with LF on multivariate analysis (hazard ratio [HR] = 1.23, p = 0.25), but was associated with a lower FFDM (HR 1.52, p = 0.005) and OS (HR 1.26, p = 0.015). In addition, multivariate analysis showed that LVI was strongly associated with increased risk of developing distant metastases (HR = 1.75, p = 0.006) and death (HR = 1.53, p = 0.003) in adenocarcinomas but not in squamous carcinomas. CONCLUSIONS: LVI is associated with an increased risk of harboring regional LN involvement. LVI is also an adverse prognostic factor for the development of distant metastases and long-term survival.

Recurrence dynamics for non-small-cell lung cancer: effect of surgery on the development of metastases.

INTRODUCTION: We study event rates over time (event dynamics) in patients undergoing surgery for early-stage non-small-cell lung cancer (NSCLC). METHODS: Using a database of patients undergoing initial surgery for NSCLC, the event dynamics, based on the hazard rate, were evaluated. Events evaluated included time to any treatment failure, local recurrence, distant metastasis (DM), and development of a second primary lung cancer. RESULTS: Among 1506 patients, time to any treatment failure dynamics demonstrated an initial surge in the hazard rate 9 months after surgery, followed by two smaller peaks at the end of the second and fourth years, respectively. This pattern was dominated by DM events. Two distinguishable peaks were noted for local recurrence in the first and second years. In contrast, the hazard rate for second primary lung cancer exhibited a more uniform pattern over time. The DM dynamics was analyzed by sex and three peaks emerged for both sexes. The timing of the first peak was similar for both sexes, at 7 to 9 months after surgery. The second peak occurred earlier in men (18-20 months) than women (24-26 months). For both sexes the third peak appeared during the fourth year. CONCLUSIONS: Recurrence dynamics of resected early-stage NSCLC displays a multipeak pattern, which supports the hypothesis of a metastasis growth model previously described for early-stage breast cancer. The model assumes both cellular and micrometastatic tumor dormancy and a transient phase of acceleration of metastatic growth following surgical excision of the primary tumor.

Local failure in resected N1 lung cancer: implications for adjuvant therapy.

PURPOSE: To evaluate actuarial rates of local failure in patients with pathologic N1 non-small-cell lung cancer and to identify clinical and pathologic factors associated with an increased risk of local failure after resection. METHODS AND MATERIALS: All patients who underwent surgery for non-small-cell lung cancer with pathologically confirmed N1 disease at Duke University Medical Center from 1995-2008 were identified. Patients receiving any preoperative therapy or postoperative radiotherapy or with positive surgical margins were excluded. Local failure was defined as disease recurrence within the ipsilateral hilum, mediastinum, or bronchial stump/staple line. Actuarial rates of local failure were calculated with the Kaplan-Meier method. A Cox multivariate analysis was used to identify factors independently associated with a higher risk of local recurrence. RESULTS: Among 1,559 patients who underwent surgery during the time interval, 198 met the inclusion criteria. Of these patients, 50 (25%) received adjuvant chemotherapy. Actuarial (5-year) rates of local failure, distant failure, and overall survival were 40%, 55%, and 33%, respectively. On multivariate analysis, factors associated with an increased risk of local failure included a video-assisted thoracoscopic surgery approach (hazard ratio [HR], 2.5; p = 0.01), visceral pleural invasion (HR, 2.1; p = 0.04), and increasing number of positive N1 lymph nodes (HR, 1.3 per involved lymph node; p = 0.02). Chemotherapy was associated with a trend toward decreased risk of local failure that was not statistically significant (HR, 0.61; p = 0.2). CONCLUSIONS: Actuarial rates of local failure in pN1 disease are high. Further investigation of conformal postoperative radiotherapy may be warranted.

How well does the new lung cancer staging system predict for local/regional recurrence after surgery?: A comparison of the TNM 6 and 7 systems.

INTRODUCTION: To evaluate how well the tumor, node, metastasis (TNM) 6 and TNM 7 staging systems predict rates of local/regional recurrence (LRR) after surgery alone for non-small cell lung cancer. METHODS: All patients who underwent surgery for non-small cell lung cancer at Duke between 1995 and 2005 were reviewed. Those undergoing sublobar resections, with positive margins or involvement of the chest wall, or those who received any chemotherapy or radiation therapy (RT) were excluded. Disease recurrence at the surgical margin, or within ipsilateral hilar and/or mediastinal lymph nodes, was considered as a LRR. Stage was assigned based on both TNM 6 and TNM 7. Rates of LRR were estimated using the Kaplan-Meier method. A Cox regression analysis evaluated the hazard ratio of LRR by stage within TNM 6 and TNM 7. RESULTS: A total of 709 patients were eligible for the analysis. Median follow-up was 32 months. For all patients, the 5-year actuarial risk of LRR was 23%. Conversion from TNM 6 to TNM 7 resulted in 21% stage migration (upstaging in 13%; downstaging in 8%). Five-year rates of LRR for stages IA, IB, IIA, IIB, and IIIA disease using TNM 6 were 16%, 26%, 43%, 35%, and 40%, respectively. Using TNM 7, corresponding rates were 16%, 23%, 37%, 39%, and 30%, respectively. The hazard ratios for LRR were statistically different for IA and IB in both TNM 6 and 7 but were also different for IB and IIA in TNM 7. CONCLUSIONS: LRR risk increases monotonically for stages IA to IIB in the new TNM 7 system. This information might be valuable when designing future studies of postoperative RT.

Factors associated with the development of brain metastases: analysis of 975 patients with early stage nonsmall cell lung cancer.

BACKGROUND: The risk of developing brain metastases after definitive treatment of locally advanced nonsmall cell lung cancer (NSCLC) is approximately 30%-50%. The risk for patients with early stage disease is less defined. The authors sought to investigate this further and to study potential risk factors. METHODS: The records of all patients who underwent surgery for T1-T2 N0-N1 NSCLC at Duke University between the years 1995 and 2005 were reviewed. The cumulative incidence of brain metastases and distant metastases was estimated by using the Kaplan-Meier method. A multivariate analysis assessed factors associated with the development of brain metastases. RESULTS: Of 975 consecutive patients, 85% were stage I, and 15% were stage II. Adjuvant chemotherapy was given to 7%. The 5-year actuarial risk of developing brain metastases and distant metastases was 10%(95% confidence interval [CI], 8-13) and 34%(95% CI, 30-39), respectively. Of patients developing brain metastases, the brain was the sole site of failure in 43%. On multivariate analysis, younger age (hazard ratio [HR], 1.03 per year), larger tumor size (HR, 1.26 per cm), lymphovascular space invasion (HR, 1.87), and hilar lymph node involvement (HR, 1.18) were associated with an increased risk of developing brain metastases. CONCLUSIONS: In this large series of patients treated surgically for early stage NSCLC, the 5-year actuarial risk of developing brain metastases was 10%. A better understanding of predictive factors and biological susceptibility is needed to identify the subset of patients with early stage NSCLC who are at particularly high risk.

Timing of local and distant failure in resected lung cancer: implications for reported rates of local failure.

INTRODUCTION: Most adjuvant lung cancer trials only report first sites of failure. The relative timing of local (i.e., local/regional) versus distant recurrence after surgery could potentially affect reported rates of local failure. We assessed this phenomenon in a large group of patients undergoing surgery for early-stage lung cancer. METHODS: This institutional review board-approved retrospective study identified all patients who underwent surgery at Duke University Medical Center for pathologic stages I to II non-small cell lung cancer between 1995 and 2005. Medical records and pertinent radiographs were reviewed to assess for local and distant sites of recurrence. Both first and subsequent failures were examined. The time interval between surgery and date of local and/or distant failure was compared using the Mann-Whitney U test. RESULTS: Of 975 patients undergoing surgery, 250 patients developed recurrent disease (43 local only, 110 distant only, and 97 both). The median time from surgery to local failure was 13.9 months (range, 1-79). The median time to distant failure was 12.5 months (range, 1-79 months). These were not significantly different (p = 0.34). Among 97 patients who experienced both local and distant failure, 72 (74%) failed at both sites simultaneously, 19 (20%) failed at local sites first, and 6 (6%) failed at distant sites first. CONCLUSIONS: The time interval from surgery to either local or distant failure is not significantly different. Patterns of failure analyses in which only first sites of failure are scored will underestimate the frequency of local recurrence. Nevertheless, the magnitude of this error is expected to be small.

Local recurrence after surgery for early stage lung cancer: an 11-year experience with 975 patients.

BACKGROUND: The objective of the current study was to evaluate the actuarial risk of local failure (LF) after surgery for stage I to II nonsmall cell lung cancer (NSCLC) and assess surgical and pathologic factors affecting this risk. METHODS: The records, including pertinent radiologic studies, of all patients who underwent surgery for T1 to T2, N0 to N1 NSCLC at Duke University between 1995 and 2005 were reviewed. Risks of disease recurrence were estimated using the Kaplan-Meier method. A multivariate Cox regression analysis assessed factors associated with LF in the entire cohort and a subgroup undergoing optimal surgery for stage IB to II disease. RESULTS: For all 975 consecutive patients, the 5-year actuarial risk of local and/or distant disease recurrence was 36%. First sites of failure were local only (25%), local and distant (29%), and distant only (46%). The 5-year actuarial risk of LF was 23%. On multivariate analysis, squamous/large cell histology (hazards ratio [HR], 1.98), stage > IA (HR, 2.02), and sublobar resections (HR, 1.99) were found to be independently associated with a higher risk of LF. For the subset of patients (n = 445) undergoing at least a lobectomy with negative surgical margins and currently considered for adjuvant chemotherapy (stage IB-II disease), the 5-year actuarial risk of LF was 27%. Within this subgroup, squamous/large cell histology (HR, 2.5) and lymphovascular space invasion (HR, 1.74) were associated with a higher risk of LF. The 5-year rate of LF was 13%, 32%, and 47%, respectively, with 0, 1, or 2 risk factors. CONCLUSIONS: Greater than half of disease recurrences after surgery for early stage NSCLC involved local sites. Pathologic factors may help to distinguish those patients at highest risk.