medwireNews: Pregnancy-associated cancers may be linked to an elevated 5-year mortality risk, but the risk varies by tumor site and time of diagnosis, suggests a population-based cohort study.
Outlining the rationale for the study, the investigators explain that “[t]here is inconsistent evidence about survival and cancer recurrence for those diagnosed with non–breast cancer malignant abnormalities during pregnancy or postpartum period.”
They therefore collated administrative data from three Canadian provinces on 24,257 premenopausal women diagnosed with cancer between January 2003 and December 2016. Of these, 1014 were diagnosed during pregnancy and 3074 during the postpartum period (defined as the 365 days after delivery), while the remaining 20,219 were diagnosed during periods remote from pregnancy.
Participants were aged an average of 31.9, 32.6, and 36.5 years in each of the three groups, respectively. Breast cancer was the most common tumor type among women diagnosed during pregnancy and remote from pregnancy, at 26% and 30%, respectively, while thyroid tumors were most common among those diagnosed postpartum, at 24%.
Amy Metcalfe (University of Calgary, Alberta, Canada) and co-researchers found no significant difference between groups with respect to 1-year survival rates, but the 5-year rates were lower among those diagnosed during pregnancy and postpartum than during periods remote from pregnancy, at 87% and 89% versus 93%, respectively.
After accounting for age and stage at diagnosis, cancer site, and days to first treatment, the mortality risk was significantly higher for pregnancy and postpartum cancers than non-pregnancy cancers, with respective adjusted hazard ratios (HRs) of 1.79 and 1.49.
“These associations persisted over some, but not all, types of cancer,” note the researchers in JAMA Oncology.
Specifically, the risk for mortality was increased for breast, ovarian, and stomach cancers diagnosed during pregnancy, at HRs of 2.01, 2.60, and 10.37, respectively, and this was also the case for breast cancers, melanomas, and brain cancers diagnosed in the postpartum period, at corresponding HRs of 1.61, 1.84, and 2.75.
“Results from our sensitivity analysis restricted to cancers where stage information was available were generally similar to the overall results that adjusted for stage,” report the study authors.
Discussing the findings, they say that “[t]here are several potential risk factors for increased mortality of patients with pregnancy-associated cancer,” such as delays in time to diagnosis and cancer treatment initiation.
And the team concludes: “More research on each cancer site is required to provide robust evidence to guide counselling and clinical care of affected patients.”
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JAMA Oncol 2023; doi:10.1001/jamaoncol.2023.0339https://oncology.medicinematters.com/prostate-cancer/genitourinary-cancers/pca-in-transgender-women-not-so-rare/25322212