Singapore is seeing a shift in the incidence of lung cancer, with rising cases among women, including those who are younger and nonsmokers, according to local research.
From 1968 to 2021, lung cancer incidence rose among women (annual average percent change [AAPC], 0.21 percent, 95 percent confidence interval [CI], 0.02–0.42) but declined among men (AAPC, −0.80 percent, 95 percent CI, −0.91 to −0.69). [Lancet Reg Health West Pac 2026;66:101779 ]
“Although rates remained consistently higher in men, the gap between men and women narrowed significantly over time (p<0.001 for interaction), driven by a steeper decline in male incidence rates,” the investigators pointed out.
Looking at age groups, the incidence rates in women increased significantly only in the 30–49-year age group (AAPC, 0.79 percent, 95 percent CI, 0.41–1.18). In men, the rates dropped across all age groups, especially in the 50–64-year group (AAPC, –1.34 percent, 95 percent CI, –1.53 to –1.12).
In terms of smoking status, the number of incident cases rose sharply among female never-smokers (AAPC, 4.06 percent, 95 percent CI, 2.99–5.11), male ever-smokers (AAPC, 3.74 percent, 95 percent CI, 2.76–4.10), and male never-smokers (AAPC, 3.33 percent, 95 percent CI, 1.62–5.12).
Lung cancer stage at diagnosis was similar between sexes, with a sharp increase in stage I diagnoses (women: AAPC, 7.19 percent, 95 percent CI, 5.24–9.22; men: AAPC, 3.79 percent, 95 percent CI, 1.94–5.46). Stage III and IV diagnoses declined substantially in the last 5 years in both women (AAPC, −5.79 percent and −2.87 percent, respectively) and men (AAPC, −3.76 percent and −2.23 percent, respectively).
The investigators noted that despite increased early-stage detection, stage IV lung cancer diagnoses remained the most common in both women and men.
Taken together, “these findings challenge the traditional perception of lung cancer as predominantly affecting men and older age groups, highlighting a shifting disease burden toward younger women. While this trend may partly reflect improved detection, late-stage diagnoses still predominate,” they said.
Explaining the shift
The observed trends in lung cancer incidence are in line with those seen across Asia, wherein rising lung cancer cases, along with thyroid and breast cancers, were reported among women and younger adults over the past decade. [Cancer Control 2022;29:10732748221095955]
“This pattern may reflect sex-based susceptibility combined with converging smoking prevalence and subtype-specific risks,” according to the investigators.
In Singapore, smoking prevalence among younger women (aged 30–49 years) increased from 1.8 percent in 1998 to 5.2 percent in 2021. Meanwhile, public health efforts raising the legal smoking age and expanding smoke-free zones have helped reduce smoking prevalence among men, from 23.1 percent in 2007 to 15.7 percent in 2023. [Diabetes Care 1999;22:241-247; https://hpb.gov.sg/community/national-population-health-survey; Asia Pac Policy Stud 2018;5:102-121]
“[Other than smoking], potential factors contributing to the rise in early-onset lung cancer among women remain unclear… Emerging evidence from other Asian populations suggests that genetic predisposition, including family history of lung cancer and distinct genomic alterations such as ERBB2 mutations and ALK rearrangements, may influence early-onset disease,” the investigators said.
Reproductive and hormonal factors (eg, early childbirth and hormone replacement therapy use) and early-life environmental exposures (eg, secondhand smoke and cooking fumes) have also been implicated, they added.
Additionally, the rising lung cancer incidence among female never-smokers “suggests a distinct disease profile in women … and is likely largely driven by adenocarcinoma,” they said.
Healthcare, policy planning
The investigators highlighted an urgent need to reassess current lung cancer management and screening strategies in Singapore, given that as many cases now occur in traditionally low-risk individuals, particularly never-smoking Asian women.
“Low-dose CT, proven to reduce mortality in high-risk smoking individuals, has seen limited local uptake due to low public awareness, lack of reimbursement, and insufficient health technology assessments,” the investigators said.
“Implementing targeted screening programs could potentially improve early detection and management, while the rising number of early-onset cases among females warrants further investigation into underlying risk factors,” they added.
TRUST platform
For the study, the investigators collected lung cancer data from government administrative and health records through the Trusted Research and Real-World Data Utilisation and Sharing Tech (TRUST) platform.
The analysis included 53,308 lung cancer cases, including 36,104 in men and 17,204 in women, documented between 1968 and 2021. Most cases occurred among the Chinese (n=46,804), followed by Malays (n=4,369) and Indians (n=1,513). Median age at diagnosis was 68.6 years. Majority of cases were diagnosed at advanced stages (3 and 4), representing 83.3 percent of males, 78.2 percent of females, 83.7 percent of ever-smokers, and 76 percent of never-smokers.