C8-03: Gender-associated differences in clinico-pathologic characteristics and survival from non-small cell lung cancer in the new era

Abstract

Since 1997, lung cancer has become the leading cause of cancer deaths for both men and women in Taiwan. Gender-related differences in terms of histologic subtypes, stage at presentation, and survival rates have been reported but with conflicting findings. There is a growing global concern regarding cancer in women. With the introduction of new diagnostic and therapeutic modalities, this study was conducted to evaluate the trends of non-small cell lung cancer (NSCLC) between genders in recent years. A cohort of consecutive patients diagnosed with NSCLC at a 180-bed referral cancer center in Taipei, who were clinically (including integrated positron emission tomography and computed tomography [PET/CT]) and pathologically staged by a surgeon and a pulmonologist experienced in video-assisted thoracoscopic surgery and trans-bronchial needle aspiration (TBNA) respectively, underwent homogenous treatment algorithms (i.e. new chemotherapeutic agents, target therapy, and 3D conformal radiotherapy) from January 2002 and followed-up until the end of 2006. Primary outcomes were the survival estimates derived by Kaplan-Meier analysis. There were 738 patients (329 women and 409 men), who presented at a similar stage (p=0.95). The women were younger (mean age: 58.4 vs. 62.2 year; p≤0.001) and better overall age-adjusted and stage-adjusted survival (p≤0.001). Stage-specific survival favored women, with the differences becoming more significant towards advanced stages (stage I disease, p=0.35; stage II, p=0.97; stage III, p=0.04; and stage IV, p≤0.001). Among the 602 patients with unequivocal pathologic diagnosis, women were more likely to have adenocarcinoma (93.95%, p≤0.001), which also comprised the majority (75.08%) in men. Patients with adenocarcinoma had better survival than those with squamous cell carcinoma (p=0.008). Pure bronchio-alveolar carcinoma (BAC) accounted for 4.95% of adenocarcinoma and disproportionately occurred in women (72%). Survival was significantly higher in patients with pure BAC histology than in those with adenocarcinoma other than BAC (p=0.02). In contrast with previous reports on recurrence patterns of BAC, an early and distinctly BAC hilar-mediastinal recurrence exclusively in female patients was diagnosed by sequential serum carcino-embryonic antigen follow-up and PET/CT-guided TBNA. There are gender-associated differences in the clinico-pathologic characteristics and survival of NSCLC patients in the new era. The results can help guide pro-active government policies regarding cancer and have the clinical importance for practicing clinician and/or researchers. Aggressive approaches to identify epidemiologic and biologic trends of lung cancer are needed at both the national and individual institution level to improve prevention, screening, and treatment efforts.