Risk of second primary smoking-related cancers following lung cancer diagnosis


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Matthew Barclay1,Georgios Lyratzopoulos2,Fiona Walter1,Robert Rintoul3
1University of Cambridge,2University College London,3Papworth Hospital NHS Foundation Trust

Abstract

Background

Improvements in management of patients with lung cancer are leading to an increasing number of long-term survivors. Detailed information about risk of smoking-related second and higher order primary cancers (SPCs) is needed to inform patients and to help optimise follow-up and surveillance regimens. We describe the risk of smoking-related SPCs (lung, bladder, laryngeal and head and neck cancers, and oesophageal squamous carcinoma) in lung cancer survivors up to ten years from first diagnosis.

Method

We examined the survival and subsequent smoking-related primary cancers of all English residents diagnosed with lung cancer between 2000-2014, followed-up until 31st December 2014 after excluding the first six months of follow-up. Stratifying by age and sex, we modelled incidence rates and standardised incidence rate ratios (SIRs, relative to incidence in the age-sex-year-matched general population), using Poisson regression models.

Results

Overall, the risk of smoking-related SPC was higher in lung cancer survivors than in the general population. For men and women aged 50-79 at diagnosis, risk of SPC was around or above 1% per patient-year from 3 years to at least 9 years following first diagnosis - significantly higher than in the age-sex-year-matched individuals in the general population (SIRs ranging from 1.4 to 3.8). Most SPCs were lung cancers (1417 of 2202), but the highest SIRs were for oesophageal squamous (SIR 2.4) and laryngeal cancers (SIR 2.8). Men and women had similar absolute risk of SPC, despite lower incidence of smoking-related cancers in women in the general population. More deprived patients were at higher risk of SPC.

Conclusion

We highlight the appreciable burden of cancer risk among lung cancer survivors. This may have implications for follow-up regimens and provide useful information to patients and their treating clinicians about surveillance and earlier detection.