[The Will-Rogers phenomenon. Stage migration in bronchogenic carcinoma after applying certainty criteria]

Radicality of lymphadenectomy in lung cancer resections by thoracotomy and video-assisted thoracoscopic approach: A prospective, multicentre and propensity-score adjusted study

OBJECTIVE

To analyse differences in intraoperative nodal assessment in patients undergoing lung cancer resection by thoracotomy and video-assisted thoracoscopy (VATS) in the Spanish Video-Assisted Thoracic Surgery Group (GEVATS).

METHODS

Prospective multicentre cohort study of anatomic pulmonary resections (n = 3533) performed from December 2016 to March 2018. Main surgical, clinical and oncological variables related with lymphadenectomy were compared according to surgical approach. Corresponding tests for homogeneity were performed. Multiple logistic regression analyses were used to determine the odds ratio (OR) and 95% confidence interval (95%CI). Covariate adjustment using the propensity score (PS) was performed to reduce confounding effects.

RESULTS

After exclusions, 2532 patients were analysed. Systematic nodal dissection (SND) was performed in 65%, with a median of resected/sampled lymph nodes (LN) of 7 (IQR 4-12) and pathologic (p) N2 and uncertain (u) pNu rates of 9.4% and 28.9%, respectively. At multivariate analysis, the following were associated with thoracotomy (OR; 95%CI): SND (1.4; 1.08-1.96; p = 0.014), staging mediastinoscopy (2.6; 1.59-4.25; p < 0.001), tumor > 3 cm (2.1; 1.66-2.78; p < 0.001), central tumor (2.5; 1.90-3.24; p < 0.001); pN1 (1.8; 1.25-2.67; p < 0.002), pN2 (1.8; 1.18-2.76; p = 0.006), lower FEV1 (0.9; 0.98-0.99; p < 0.001), squamous cell carcinoma (1.5; 1.16-1.98; p = 0.002) and inexperienced surgeons in VATS (compared with > 100 VATS experience) (37.6; 13.55-104.6; p < 0.001). After PS adjustment, SND maintained the OR, but in the limit of signification (1.4; 1-1.98; p = 0.05). Nodal upstaging was significantly higher in the thoracotomy group. Complication rates of SND and no SND were similar.

CONCLUSIONS

Thoracotomy was associated with a more thorough lymphadenectomy in GEVATS. Therefore, intraoperative lymph node evaluation performed at VATS should be improved to have better prognostic information and more solid grounds to indicate adjuvant therapy.

[The Will Rogers phenomenon and its impact on imaging diagnostics]

The Will Rogers phenomenon is a possible cause of systematic distortions in the results of clinical studies, which can be produced if stage migration occurs during a disease. The term refers to the apparent paradox which is observed when an element is changed from one set to another and the average values of both sets are altered in the same way. The effect is due to the prerequisite that the numerical value of the element being moved is placed between the mean values of both groups. In medicine, this phenomenon is a consequence of the evolution of staging procedures and may be source of misleading statistics for survival in cancer. Both advanced pathological assessment and modern imaging techniques may be involved. The wrong conclusions are induced by comparing the effects of treatment in contemporary patient groups, which profit from extensive diagnostic procedures, to those of historical controls. Treatise informs about the history of the term and illustrates its effects by numerical examples and clinical data. Finally, a model computation based on current PET/CT figures is offered.

[Bronchioloalveolar carcinoma in Spain: a rare and different form of lung cancer]

OBJECTIVE

To describe a series of cases of bronchioloalveolar carcinoma (BAC) treated surgically between 1993 and 1997 in the 19 hospitals that make up the Bronchogenic Carcinoma Cooperative Group of the Spanish Society of Pulmonology and Thoracic Surgery (GCCB-S).

PATIENTS AND METHODS

From a total of 2,944 cases of non-small cell lung cancer (NSCLC), 82 (3%) were BAC. The clinical characteristics and prognosis of patients with BAC were compared with those of the remaining 2,862 patients with NSCLC.

RESULTS

The percentage of men was lower for BAC than for other types of NSCLC (64.6% compared with 93.5%; P< .001) and BAC was associated with less comorbidity (50% vs 62%; P< .05), particularly in terms of chronic obstructive pulmonary disease (33% vs 47.2%; P< .05). Other characteristics showing significant differences were the higher frequency of BAC as a chance finding and the lower likelihood of weight loss or reduced performance status at the time of diagnosis. Classification as stage cI was significantly more common in patients with BAC (87% vs 75%; P.001), and this difference between groups was more pronounced for stage pI (68.5% vs 47%; P< .01). Only taking into account patients classified as stage pI with complete resection of NSCLC and following exclusion of operative mortality, patients with BAC presented an overall 5-year survival of 65% (95% confidence interval [CI], 51%-79%), compared with a significantly lower survival of 53% (95% CI, 50%-56%; P< .05) in patients with other forms of NSCLC.

CONCLUSIONS

In Spain, among cases of lung cancer treated by surgery, BAC is very rare (3%) and displays clinical characteristics that are different from other forms of NSCLC. Controlling for the most basic prognostic factors (stage pI and complete resection), survival is significantly higher for BAC.

Results of surgery in small cell carcinoma of the lung

OBJECTIVE

The experiences published by various groups have re-opened the debate on the role of surgery in the management of patients with small cell lung cancer, especially in those with early stage disease (T1-T2 N0). Our study reports the survival rate of 47 patients with small cell lung cancer treated surgically.

PATIENTS AND METHODS

Ours is a prospective study that selected patients with lung cancer recommended for surgery (n=2994) between 1993 and 1997 based on operability criteria accepted by the Bronchogenic Carcinoma Cooperative Group of the Spanish Society of Pneumology and Thoracic Surgery. We report the clinical as well as pathological stages of the patients with small cell lung cancer (n=47), later analysing the 5-year survival rate after surgery using the Kaplan-Meier method.

RESULTS

In 31 patients (66%), resection was complete; 3 patients (6%) received induction treatment and 30 (64%) adjuvant treatment. Five years later, 26% (95% CI 12-40%) of the patients that received surgical treatment were still alive. When we analysed the patients that underwent complete resection, 31% (95% CI 13-49%) survived 5 years or more. In patients at stage Ip (n=15), 36% (95% CI 11-61%) were still living after 5 years.

CONCLUSION

Until future studies compare surgery plus chemotherapy versus chemotherapy and radiotherapy, it seems reasonable to offer surgical treatment to those patients with early stage small cell lung cancer (T1-T2-N0).

Heterogeneity of prognostic profiles in non-small cell lung cancer: too many variables but a few relevant

OBJECTIVE

Many prognostic factors, exceeding 150, for non-small cell lung cancer (NSCLC) are mentioned in the literature. The different statistical weight of the some variables at issue, their heterogeneity and their clinical uselessness is reviewed.

STUDY DESIGN AND SETTING

Survival analysis of a cohort of NSCLC operated (n = 1730, 1993-1997) was carried out utilizing different statistical approaches: Cox proportional hazard analysis (CPHA), logistic regression (LRA), and recursive partitioning (CART).

RESULTS

CPHA identified 13 prognostic variables and 11 LRA. Of the 17 possible variables, 10 are coincident. CART provided five different diagnostic groups but only three differentiated survival levels. Parsimonious models were constructed including only T and N cancer staging variables. Areas under the ROC curve of 0.68 and 0.68 were found for CPHA and LGA parsimonious models respectively, and 0.72 and 0.71 for complete models.

CONCLUSION

Variables with a minimal impact on the respective models and thus with little or scarce predictive clinical repercussion were identified. Differences in the prognostic profile of survival can be caused by the different methodological approaches used. No relevant differences were found between the parsimonious and complete models. Although the amount of information managed is considerable, there continues to be a large predictive gap yet to be explained.

Previous tumour as a prognostic factor in stage I non-small cell lung cancer

OBJECTIVE

To evaluate the effect of comorbidity as an independent prognostic factor in lung cancer.

METHOD

Data on 2991 consecutive cases of lung cancer were collected prospectively from 19 Spanish hospitals between 1993 and 1997 by the Bronchogenic Carcinoma Cooperative Group of the Spanish Society of Pneumology and Thoracic Surgery (GCCB-S). To evaluate the effect of comorbidity on survival, 1121 patients with non-small cell lung cancer (NSCLC) in pathological stage I who underwent complete resection were selected, excluding operative mortality. The presence of specific comorbidities at the time of thoracotomy was registered prospectively.

RESULTS

Cox regression analysis showed that tumour size (0-2, 2-4, 4-7, >7 cm) (HR 1.45 95% CI 1.08 to 1.95), 1.86 (95% CI 1.38 to 2.51), 2.84 (95% CI 1.98 to 4.08)), the presence of a previous tumour (HR 1.45 (95% CI 1.17 to 1.79)) and age (HR 1.02 (95% CI 1.01 to 1.03)) had a significant prognostic association with survival. This study excluded the presence of visceral pleural involvement or other comorbidities as independent variables.

CONCLUSION

The presence of a previous tumour is an independent prognostic factor in pathological stage I NSCLC with complete resection, increasing the probability of death by 1.5 times at 5 years. It is independent of other comorbidities, TNM classification and age.

Survival of 2,991 Patients With Surgical Lung Cancer

OBJECTIVE

To evaluate the current staging system of lung cancer, taking into account different selection criteria for the studied population.

POPULATION

A total of 2,991 consecutive patients with surgical lung cancer were prospectively compiled from 19 Spanish hospitals (Bronchogenic Carcinoma Cooperative Group of the Spanish Society of Pneumology and Thoracic Surgery) between 1993 and 1997.

METHODS

The Kaplan-Meier method was used to calculate survival at 5 years (S5) for each pathologic stage, and the log-rank test was used for comparison purposes. These studies were performed in the total group (population 1, n = 2,972); excluding operative mortality and small cell lung cancer cases (population 2, n = 2,697); excluding cases with induction therapy (population 3, n = 2,542); excluding cases with exploratory thoracotomy (population 4, n = 2,304); and, lastly, excluding cases with incomplete resection (population 5, n = 2082) [70% of the initial population].

RESULTS

The global S5 was similar in populations 1, 2, and 3: 34% (95% confidence interval [CI] 32 to 36%), 37% (95% CI, 35 to 39%), and 38% (95% CI, 35 to 39%), but different from that of populations 4 and 5: 40% (95% CI, 39 to 43%) and 43% (41 to 45%), respectively. For pathologic stage I, pathologic stage II, and pathologic state IIIA (pIIIA), S5 was similar in the five reported populations. In pathologic stage IIIB (pIIIB), there were differences in S5 between populations 1, 2, and 3 (13 to 15%; 95% CI, 10 to 19%) and populations 4 and 5 (26 to 29%; 95% CI, 19 to 38%). In population 4, there was no significant prognostic difference between two specific stage groups, that is between pathologic stage IB (pIB) and pathologic state IIA (pIIA) [p = 0.70] and between pIIIA and pIIIB (p = 0.79); the pathologic T3N2M0 combination has a S5 (13%) lower than that for pIIIB (26%).

CONCLUSION

The definition of the population that constitutes the denominator for the analysis of survival in surgical lung cancer is important in pIIIB. The inclusion or exclusion of cases without resection is the most important factor for the selection of such population. This study detected that there are no prognostic differences between pIB and pIIA, and between pIIIA and pIIIB.

Importance of Routine Mediastinal Staging in Women With Nonsmall Cell Lung Cancer

OBJECTIVE

To study the specific importance of mediastinal staging in women with nonsmall cell lung cancer.

PATIENTS AND METHODS

Between July 1981 and September 2003 we surgically staged 2172 patients with nonsmall cell lung cancer who met the inclusion criteria for resectability and operability. A subgroup of 108 women was studied. Cervical mediastinoscopy was performed in all cases, with the addition of anterior mediastinotomy in cases with left upper lobe involvement. All patients underwent a preoperative computed tomography chest scan.

RESULTS

Cervical mediastinoscopy was performed on all 108 patients, 26 of whom also underwent anterior mediastinotomy. Positive findings were recorded in 44 (40.7%) of the 108 cases: 39 of the 108 mediastinoscopies (36.1%), 9 of the 26 mediastinotomies (34.6%), and in 5 cases (19.2%) both mediastinoscopy and mediastinotomy. Nodal involvement was found in 13% of cases in clinical stage IA and 30.8% of cases in clinical stage IB. The percentage of positive findings was significantly higher for cases with adenocarcinoma or large cell carcinoma (P<.05). We performed 67 thoracotomies: 46 patients underwent lobectomy (42.6% of the 108), 7 bilobectomy (6.5%), 9 pneumonectomy (8.3%), and 5 exploratory thoracotomy (4.6%). The agreement between clinical staging after mediastinoscopy and pathological staging after thoracotomy was 47% (stage IA) and 57% (stage IB).

CONCLUSIONS

Routine mediastinoscopy is indicated for all women with nonsmall cell lung cancer, regardless of clinical stage.