Differences in cancer survival by sex: a population-based study using cancer registry data

Our plain-English summary of Differences in cancer survival by sex: a population-based study using cancer registry data, by N. Afshar, D.R. English, V. Thursfield, et al (Cancer Causes & Control, 2018).

The study

• Authors: N. Afshar, D.R. English, V. Thursfield, P.L. Mitchell, L. Te Marvelde, H. Farrugia, G.G. Giles, R.L. Milne
• Journal: Cancer Causes & Control
• Published: 2018;29(11):1059-1069
• Cited by: 44 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Purpose: Few large-scale studies have investigated sex differences in cancer survival and little is known about their temporal and age-related patterns.

Methods: We used cancer registry data for first primary cancers diagnosed between 1982 and 2015 in Victoria, Australia. Cases were followed until the end of 2015 through linkage to death registries. Differences in survival were assessed for 25 cancers using the Pohar-Perme estimator of net survival and the excess mortality rate ratio (EMRR) adjusting for age and year of diagnosis.

Results: Five-year net survival for all cancers combined was lower for men (47.1%; 95% CI 46.9-47.4) than women (52.0%; 95% CI 51.7-52.3); EMRR 1.13 (95% CI 1.12-1.14; p < 0.001). A survival disadvantage for men was observed for 11 cancers: head and neck, esophagus, colorectum, pancreas, lung, bone, melanoma, mesothelioma, kidney, thyroid, and non-Hodgkin lymphoma. In contrast, women had lower survival from cancers of the bladder, renal pelvis, and ureter. For the majority of cancers with survival differences, the EMRR decreased with increasing age at diagnosis; for colorectal, esophageal, and kidney cancer, the EMRR increased with time since diagnosis.

Conclusion: Identifying the underlying reasons behind sex differences in cancer survival is necessary to address inequalities, which may improve outcomes for men and women.

In plain English

This population-based study used Victorian Cancer Registry data on 412,471 people (239,517 men and 172,954 women) aged 15 to 99 with a first primary cancer diagnosed in Victoria, Australia, from 1982 to 2015 and followed to the end of 2015. Survival was compared between men and women for 25 cancer types, adjusting for age and year of diagnosis. It did not study asbestos or any other exposure. Five-year net survival for the 25 cancers combined was 47.1% (95% CI 46.9 to 47.4) for men and 52.0% (95% CI 51.7 to 52.3) for women. Men had lower survival for 11 cancers, one of which was mesothelioma. Women had lower survival for cancers of the bladder, renal pelvis and ureter. For mesothelioma (2,413 men, 534 women), five-year age-standardized net survival was 5.1% (95% CI 4.2 to 6.3) for men and 8.4% (95% CI 6.0 to 11.3) for women (p value 0.03). The authors concluded that identifying the reasons for sex differences in survival is necessary to address inequalities. They noted they lacked data on cancer stage, treatment, co-morbidities and lifestyle behaviors.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Population-based retrospective cohort study using cancer registry data linked to death registries
• Who was studied: 412,471 people (239,517 men and 172,954 women) aged 15 to 99 years with a first primary cancer of one of 25 types, diagnosed in Victoria, Australia, between 1982 and 2015. Sex-specific cancers and breast cancer were excluded.
• Exposure: Sex (men compared with women). The study did not examine asbestos, fiber types, occupations, or any other exposure.
• Main results:
  • For the 25 cancers combined, five-year net survival was 47.1% (95% CI 46.9 to 47.4) for men and 52.0% for women
  • For the 25 cancers combined, women's five-year net survival had a 95% CI of 51.7 to 52.3. The excess mortality rate ratio for men relative to women was 1.13 (95% CI 1.12 to 1.14; p less than 0.001).
  • Men had a survival disadvantage for 11 cancers: head and neck, esophagus, colorectum, pancreas, lung, bone, melanoma, mesothelioma, kidney, thyroid, and non-Hodgkin lymphoma
  • Mesothelioma: 2,413 men (2,275 deaths) and 534 women (476 deaths). Five-year age-standardized net survival was 5.1% (95% CI 4.2 to 6.3) for men and 8.4% (95% CI 6.0 to 11.3) for women; likelihood ratio test p value 0.03.
  • Women had lower survival than men from cancers of the bladder, renal pelvis, and ureter
  • The largest difference was for melanoma, where men had about twofold higher excess mortality than women (EMRR 2.02; 95% CI 1.86 to 2.19)
• The authors' conclusion: The authors concluded that identifying the underlying reasons behind sex differences in cancer survival is necessary to address inequalities, which may improve outcomes for men and women.
• Limitations the authors state:
  • No data were available on cancer stage at diagnosis, treatment, co-morbidities, or health-related lifestyle behaviors, so their role in the sex differences could not be explored
  • No information was available on smoking status, which the authors note is strongly associated with lung cancer histological type and expected survival

Topics

Medical terms in this study, explained in our Lexicon: Cancer Registry, rate ratio, Mesothelioma.

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• Cancer survival and prevalence in Australia: period estimates from 1982 to 2010 — Australian Institute of Health and Welfare (2013)
• Impact of malignant mesothelioma in Taiwan: a 27-year review of population-based cancer registry data — L.J. Lee, Y.Y. Chang, et al. (2010)
• Malignant Peritoneal Mesothelioma: Patterns of Care and Survival in the Netherlands: A Population-Based Study — N.L. de Boer, J.P. van Kooten, et al. (2019)
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