Survival by sex and HIV status in patients with anal cancer in the USA between 2001 and 2019: a retrospective cohort study

Identifying risk factors for anal cancer in people with HIV in Spain: a multicentre retrospective cohort study nested in the PISCIS cohort

BACKGROUND

People with HIV have a substantially higher risk of anal cancer than the general population. We aimed to identify risk factors associated with the development of anal cancer among people with HIV to implement more effective and targeted screening strategies.

METHODS

We conducted a multicentre retrospective cohort study in 16 hospitals across Catalonia and the Balearic Islands, Spain, between Jan 1, 1998, and Dec 31, 2022. Treatment-naive people with HIV nested in the PISCIS cohort aged 16 years and older with biopsy-proven squamous cell carcinoma of the anus or anal canal were eligible for inclusion. Data were retrieved from every hospital registry and were centrally validated in the PISCIS cohort and the Public Data Analysis for Health Research and Innovation Program. The primary outcome was the incidence rate (IR) of histologically confirmed anal cancer. We used Poisson regression to examine the association between the following risk factors and incidence of anal cancer: age, mode of HIV transmission, nadir CD4 cell count, and time period of HIV diagnosis.

FINDINGS

Among 14 238 people with HIV, 107 (0·8%) developed anal cancer, with an overall IR of 72·5 cases per 100 000 person-years (95% CI 59·4-87·6) and median follow-up of 9·5 years (IQR 4·4-15·7). Of these patients with anal cancer, 37 (34·6%) died, of which 24 (64·9%) deaths were related to anal cancer. Incidence was highest among people with HIV with historical nadir CD4 counts of less than 200 cells per μL (IR 105·0 person-years, 95% CI 82·0-132·5) and lowest among those with counts of more than 350 cells per μL (2·9 person-years, 0·1-16·0). Among men who have sex with men (MSM), the IR was 211·5 person-years (95% CI 151·1-211·7) among those with a CD4 count of less than 200 cells per μL, 37·6 person-years (16·2-74·1) among those with a count of 200-350 cells per μL, and 4·8 person-years (0·1-26·9) among those with a count of more than 350 cells per μL. Among people with HIV younger than 30 years, there were no cases of anal cancer among women or men who do not have sex with men, and one case among MSM with a nadir CD4 count of more than 350 cells per μL (IR 4·8 person-years, 95% CI 0·1-26·9). In the multivariable analysis, people with HIV with nadir CD4 counts of more than 350 cells per μL had the lowest risk of developing anal cancer, compared with people with HIV with counts of less than 200 cells per μL (adjusted IR ratio 0·03, 95% CI 0·00-0·25; p=0·0010) or 200-350 cells per μL (0·30, 0·17-0·55; p<0·0001). Compared with people with HIV younger than 30 years, people with HIV aged 60 years and older had an adjusted IR ratio of 27·6 (3·7-206·9; p=0·0010) and people with HIV aged 45-59 years of 21·6 (3·0-156·4; p=0·0020). Compared with individuals diagnosed after 2015, a diagnosis of HIV before 1998 had an adjusted IR ratio of 33·0 (7·9-137·5; p<0·0001).

INTERPRETATION

A nadir CD4 count threshold below 350 cells per μL, particularly less than 200 cells per μL, has the potential to identify people with HIV at heightened risk of developing anal cancer. Customised screening strategies that prioritise screening for individuals at high risk with this surrogate marker could maximise available resources. External validation of these data with other cohorts is required before screening recommendations can be updated.

FUNDING

Catalan Health Department, Generalitat de Catalunya.

Biomarkers of pembrolizumab efficacy in advanced anal squamous cell carcinoma: analysis of a phase II clinical trial and a cohort of long-term responders

BACKGROUND

Recent trials suggest that programmed cell death 1 (PD-1)-directed immunotherapy may be beneficial for some patients with anal squamous cell carcinoma and biomarkers predictive of response are greatly needed.

METHODS

This multicenter phase II clinical trial (NCT02919969) enrolled patients with metastatic or locally advanced incurable anal squamous cell carcinoma (n=32). Patients received pembrolizumab 200 mg every 3 weeks. The primary endpoint of the trial was objective response rate (ORR). Exploratory objectives included analysis of potential predictive biomarkers including assessment of tumor-associated immune cell populations with multichannel immunofluorescence and analysis of circulating tumor tissue modified viral-human papillomavirus DNA (TTMV-HPV DNA) using serially collected blood samples. To characterize the clinical features of long-term responders, we combined data from our prospective trial with a retrospective cohort of patients with anal cancer treated with anti-PD-1 immunotherapy (n=18).

RESULTS

In the phase II study, the ORR to pembrolizumab monotherapy was 9.4% and the median progression-free survival was 2.2 months. Despite the high level of HPV positivity observed with circulating TTMV-HPV DNA testing, the majority of patients had low levels of tumor-associated CD8+PD-1+ T cells on pretreatment biopsy. Patients who benefited from pembrolizumab had decreasing TTMV-HPV DNA scores and a complete responder's TTMV-HPV DNA became undetectable. Long-term pembrolizumab responses were observed in one patient from the trial (5.3 years) and three patients (2.5, 6, and 8 years) from the retrospective cohort. Long-term responders had HPV-positive tumors, lacked liver metastases, and achieved a radiological complete response.

CONCLUSIONS

Pembrolizumab has durable efficacy in a rare subset of anal cancers. However, despite persistence of HPV infection, indicated by circulating HPV DNA, most advanced anal cancers have low numbers of tumor-associated CD8+PD-1+ T cells and are resistant to pembrolizumab.