Multiple primaries now account for 16% of the newly diagnosed malignancies reported in the US National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program.
The primaries accounted for the difference.
To account for differences in the registration of multiple primaries, for incidence estimation of invasive and in situ BRC, only the first cancer of the respective tumour type was considered.
In addition, heterogeneity has been detected not only between primary tumour and metastases, which could be explained by multiple primaries or occult primaries, but also between metastases, and this explanation certainly could not account for the rates of discordance seen.
Those candidacies withered once they headed south for the multiple primaries in larger states.
Women whose first primary is the breast account for 25% of survivors with multiple cancers, followed by colorectal cancer (15%) as the first primary in both men and women, according to SEER data. 2 In the present study, the most common initial primary among cancer survivors with multiple primaries for both men and women was breast, prostate, and colorectal.
Unlike other studies which focused on specific cancers, our comparison of reporting characteristics was done overall and by cancer type, and accounted for women with multiple primary cancers in a pregnancy.
Poisson regression taking account of the multiple primary events gave an incidence rate ratio (IRR) of 0.56 (95% CI 0.32 to 0.99, p=0.05).
The SEER definition takes into account, when determining multiple primary tumours, the site of the tumour, behaviour of the second tumour, histology, date of diagnosis, and the laterality if it is a paired organ (Fritz and Ries, 1998).
These findings also contradict the hypothesis that an epigenetic field defect may predispose to MSS synchronous neoplasia, which account for the vast majority of multiple primary colorectal malignancies (Leggett and Worthley, 2009).
