HPV prevalence in penile carcinoma
Tuesday, 27 April 2010- A group of researchers in Sweden examined human papillomavirus (HPV) prevalence and its links to histopathological status in penile carcinoma. They presented their findings during the abstract session at the recently concluded 25th Anniversary EAU Congress held in Barcelona, Spain.
“Penile carcinoma is a rare malignancy in the western world. In Sweden, the annual incidence is 2.2 per 100,000 men. Penile carcinoma has many similarities with cervical carcinoma where nearly all tumours are human papillomavirus (HPV) positive,” said P. Kirrander and colleagues.
The researchers said the predominant HPV types in cervical carcinoma (around 70 %) are HPV 16 and 18, and prophylactic vaccines have recently been introduced. In reported patient materials, the prevalence of HPV in penile carcinoma varies between 42 % and 82 %.
“The large variation in positive findings might depend on methodological differences, differences among the investigated populations and small study groups. In the present study, the aim was to investigate the prevalence of HPV in a large Swedish cohort and correlate the data to histopathological parameters in order to determine the prognostic value of HPV status,” the researchers wrote.
A total of 241 patients with penile squamous cell carcinoma treated at the University Hospital in Örebro, Sweden, between 1986 and 2008 were included. The mean age at diagnosis was 65. All tumours were classified according to the current TNM classification. 100 patients were operatively staged with regard to lymph node metastasis. All tissue samples were formalin fixed and paraffin embedded.
Three 0.6 mm cores of tumour tissue where punched out of the paraffin block. DNA was extracted, subsequently quality and quantity of DNA was determined. Real Time PCR was used to detect 13 different types of HPV (6,11,16,18,31,33,35,45,51,52,56,58 and 59). All samples were analyzed in duplicate and positive controls were used.
The results showed that 26 out of 241 patients were excluded due to low quality of the extracted DNA. HPV was detected in 178 of the remaining 215 (82.9 %) tumour samples. A single HPV infection was seen in 71 %, a double in 25 % and multiple HPV infections (>2 types) in 4 % of the HPV positive tumour samples.
The most common HPV type was HPV 16, present in 42 % of all tumour samples, followed by simultaneous HPV 16 and 18 (12 %) and HPV 18 alone ( 10%). In total 76 % of the patients were infected by either or both HPV 16 and HPV 18. No correlation between HPV status (neg vs pos; HPV 16/18+ vs non 16/18) to tumour extent (pTis-pT3), grade (G1-G3) nor nodal status (pN0 or pN+) was observed.
"The present study of HPV prevalence in penile carcinoma is one of the largest. The prevalence found (82.8 %) is higher than reported in most other studies. According to our data HPV 16 and/or 18 prevalence in penile carcinoma is comparable to what is seen in cervical carcinoma, raising the question of what effect HPV vaccine could have on penile carcinoma incidence," the researchers said.
"There was no significant correlation between HPV status and histopathological parameters, subsequently HPV has no prognostic value according to our data," they added.
Source: P. Kirrander, et al., "Human papillomavirus prevalence and correlation to histopathological status in penile carcinoma," Abstract 551, 25th Anniversary EAU Congress, Barcelona, Spain.
