PHILADELPHIA – Between 2015 and 2022, men were more likely than women to be diagnosed with regional and/or distant stages of 20 nonreproductive solid cancer types in the United States, according to a study published in Cancer Epidemiology, Biomarkers & Prevention , a journal of the American Association for Cancer Research (AACR).
The study's findings may provide insight into the discrepancies between men and women for cancer outcomes, the researchers noted.
"We know that, overall, males are more likely than females to die from many types of cancer. We also know that cancer stage at diagnosis is a key predictor of cancer survival," said the study's lead author, Beth Maclin, PhD, MPH , a postdoctoral fellow in the Division of Cancer Epidemiology and Genetics at the National Cancer Institute (NCI). Maclin explained that cancer stage at diagnosis is an important prognostic factor; in general, the more advanced a cancer's stage at diagnosis, the worse the patient's prognosis tends to be.
"It is important to better understand how stage may differ between sexes as a way to explain sex differences in cancer mortality and to identify potential intervention points to improve cancer survival for everyone," Maclin said.
Maclin and colleagues analyzed the stage at diagnosis of 2,401,772 cases of cancer in the United States from the NCI's Surveillance, Epidemiology, and End Results (SEER) 21 database from 2015 to 2022. The research team sought to identify the association between sex and stage of disease at diagnosis for 30 different nonreproductive solid organ tumors. Cancer stages were defined as localized (cancer that has not spread beyond its site of origin); regional (cancer that has spread to nearby lymph nodes); or distant (metastatic cancer that has spread to other organs and/or distant lymph nodes). Regional and distant cancers were considered later-stage. The analysis was adjusted for differences in age and year of diagnosis, and the study did not analyze sex-specific cancers.
For 16 cancer sites, men were significantly more likely than women to be diagnosed at a regional stage than at a localized stage. The largest differences were observed for salivary gland cancer , oropharyngeal cancer , thyroid cancer , and stomach cancer . Compared with women, men were more likely to be diagnosed with regional tongue cancer (151%), regional salivary gland cancer (93%), regional oropharyngeal cancer (80%), regional thyroid cancer (74%), and regional stomach cancer (67%).
Men were also significantly more likely than women to be diagnosed at a distant stage than a localized stage for 17 cancer sites. Of these, melanoma and cancers of the tongue, thyroid, salivary gland, and stomach had the largest differences. Men had 134% greater odds of distant tongue cancer, 128% greater odds of distant thyroid cancer, 97% greater odds of distant salivary gland cancer, 56% greater odds of distant stomach cancer, and 50% greater odds of distant melanoma.
For a small number of cancer sites, men were less likely than women to be diagnosed at later stages. Men with laryngeal or bladder cancer were less likely than women to be diagnosed with a regional case than a localized case (40% less likely and 20% less likely, respectively). Additionally, men diagnosed with bladder, anal, or liver cancer were less likely to be diagnosed with a distant case than women (31%, 16%, and 13% less likely, respectively).
Similar patterns were observed across different races/ethnicities and county-level median household income levels.
The factors that could account for the observed sex-specific differences, Maclin said, are myriad.
"There are a variety of possible explanations for why we found sex differences among most cancer sites we studied. One explanation could be differences in cancer screening uptake for sites that can be detected through screening. It is also possible that there are differences in health care-seeking behaviors; existing research shows that women go to the doctor more than men, which could mean more opportunities for clinicians to catch cancer symptoms earlier, thus leading more women to get diagnosed at the localized stage instead of regional or distant stages," Maclin said. "There is also the possibility that the way clinicians perceive cancer symptoms in males and females differ, leading to different types of diagnostic tests or treatment plans, which can either hasten or delay cancer diagnosis."
Regardless of why men were more likely to be diagnosed at later stages for these cancer types, Maclin noted, early detection and habitual engagement with health care providers remains critical to preventing metastatic cancer: "My overall message is that everyone should go to the doctor regularly. Don't delay seeing a doctor if you notice something has changed in your body."
The study's limitations include the lack of certain variables in the dataset that could have explained some of the trends, such as insurance coverage; use of SEER staging data, which allowed for many years of analysis but which is less specific than the tumor-node-metastasis (TNM) staging system typically used in the clinic; and missing staging data in more than 10% of lip, esophagus, stomach, liver, pleura, bone and joint, and eye and orbit cancer cases.
The study was funded by the Intramural Research Program of the National Institutes of Health. Maclin declares no conflicts of interest.
