Association between invasive squamous cell carcinoma of the vulva and ABO blood group

To determine whether the distribution of ABO blood group among women with invasive squamous cell carcinoma (SCC) of the vulva is different from that among a population of women treated for nonneoplastic gynecologic disease.

A retrospective analysis of pathology reports and blood bank records from January 1996 through September 2003 was performed. The distribution of ABO blood group for 33 women diagnosed with invasive SCC of the vulva was determined. ABO blood group was also recorded for 100 female patients (controls) who underwent a gynecologic procedure for a nonneoplastic process during the period January 2003 through November 2003. The blood group phenotype distribution for the study groups and the controls was compared by an incidence ratio.

Statistical analysis gave an incidence ratio for blood group types A and O of 1.55 (p < .20) when the patients with invasive SCC of the vulva were compared with the controls. The p value was not significant. Similarly, the incidence ratio for blood group types B and O equaled 0.386 (p = 1). Again the p value was not significant. In fact, none of the incidence ratios calculated were statistically significant. Although not statistically significant, the incidence ratio for the invasive vulvar SCC group was >1. This may indicate that there is a trend for women with invasive SCC of the vulva to have blood group type A.

Results of this study do not suggest an association between blood group type A, or any other blood group, and vulvar SCC. This study was similar in patient size to another study (33 patients with vulvar SCC vs. 39 patients with vulvar SCC, respectively). The disparity of the results in determining the significance of blood group type A as an associated factor for vulvar SCC in this and the other study may be due to the limited size of the study populations. Additional investigation is needed to further evaluate this issue.