The Reality of Lung Cancer Paradox: The Impact of Body Mass Index on Long-Term Survival of Resected Lung Cancer. A French Nationwide Analysis from the Epithor Database

Abstract

Obesity could have a protective effect in patients with lung cancer. We assessed the prognostic role of preoperative BMI on survival in patients who underwent lung resection for NSCLC. A total of 54,631 consecutive patients with resectable lung cancer within a 15-year period were extracted from Epithor (the French Society of Thoracic and Cardiovascular Surgery database). Patient subgroups were defined according to body mass index (BMI): underweight (BMI < 18.5 kg/m2), normal weight (18.5 ≤ BMI < 25 kg/m2), overweight (25 ≤ BMI < 30 kg/m2), and obese (BMI ≥ 30 kg/m2). Underweight was associated with lower survival (unadjusted HRs 1.24 (1.16–1.33)) compared to normal weight, whereas overweight and obesity were associated with improved survival (0.95 (0.92–0.98) and 0.88 (0.84–0.92), respectively). The impact of BMI was confirmed when stratifying for sex or Charlson comorbidities index (CCI). Among patients with obesity, a higher BMI was associated with improved survival. After adjusting for period of study, age, sex, WHO performance status, CCI, side of tumor, extent of resection, histologic type, and stage of disease, the HRs for underweight, overweight, and obesity were 1.51 (1.41–1.63), 0.84 (0.81–0.87), and 0.80 (0.76–0.84), respectively. BMI is a strong and independent predictor of survival in patients undergoing surgery for NSCLC.

Twenty-Year Survival of Patients Operated on for Non-Small-Cell Lung Cancer: The Impact of Tumor Stage and Patient-Related Parameters

“…Like our findings for the stage of disease, most risk factors identified in our study as predictors of late survival have also been identified as affecting shorter term (5 or 10-year) survival rates, in particular: age [ 22 , 31 ], chronic bronchitis [ 35 ], COPD [ 6 , 17 ] FEV1% [ 10 , 17 , 22 ], smoking history [ 22 ] or cumulative smoking [ 9 , 10 , 17 , 22 , 31 ], nutritional status [ 22 ], BMI [ 12 ], weight loss [ 14 ], and systemic inflammation.…”

“…With respect to very long-term survival, the same cohort was used as in previous studies with a 5- to 7-year follow-up assessment [ 14 , 32 , 35 ]. We updated data on later vital status by direct interrogation (in April 2021) of the French INSEE (Institut National de la Statistique et des Etudes Economiques) open-source national database (i.e., open-link Internet), which is already used for the assessment of lung cancer survival after surgical treatment by the French Epithor team [ 12 ]. The INSEE database is not exhaustive for foreign patients (even those having spent a long period in France), so among those patients born outside France, we considered as dead those stated as dead in the INSEE database, but we excluded the remaining cases from the study ( n = 25).…”

“…The impact of other patient-related factors is currently gaining interest: thinner corpulence [ 11 , 12 ] or sarcopenia [ 11 , 13 ] have been shown to negatively affect 11-year survival after lobectomy [ 7 ]. On the other hand, body overweight (BMI ≥ 25 Kg/m 2 ) and obesity (BMI ≥ 30 Kg/m 2 ) may play a protective role at 5 and 7 years [ 12 , 14 , 15 , 16 ].…”

“…The impact of other patient-related factors is currently gaining interest: thinner corpulence [ 11 , 12 ] or sarcopenia [ 11 , 13 ] have been shown to negatively affect 11-year survival after lobectomy [ 7 ]. On the other hand, body overweight (BMI ≥ 25 Kg/m 2 ) and obesity (BMI ≥ 30 Kg/m 2 ) may play a protective role at 5 and 7 years [ 12 , 14 , 15 , 16 ]. Although obesity is a risk factor for carcinogenesis in at least 20 cancer types, epidemiological studies have consistently demonstrated a lower risk of developing lung cancer and of dying after treatment in overweight/obese patients, referred to as the “lung cancer obesity paradox” [ 17 , 18 ].…”

“…Apart from institutional studies, some registries have also reported on the long-term survival rates of resected lung cancer patients: two European registries, namely the Norway and the French Epithor databases, reported on 5-year and 11-year survivals, respectively [ 12 , 25 ], while North American registries assessed figures at 10 years [ 26 ] and, for patients older than 65 years, at 14 years [ 25 , 27 , 28 ]. An analysis based on the database of the Society of Thoracic Surgeons (STS) revealed the following factors to be associated with 7-year survival: increased age, male sex, smoking history, BMI (BMI < 18.5, 18.5 ≤ BMI < 25, 25 ≤ BMI < 30, 30 ≤ BMI < 35, BMI ≤ 35), and decreased preoperative forced expiratory volume in 1 s. (percentage of normal value FEV1% (FEV1% < 40%, 40% ≤ FEV1% < 60%, 60% ≤ FEV1% < 80, 80% ≤ FEV1%) [ 20 ].…”