VIROLOGICAL RESPONSE AND EFFECTIVENESS OF CHEMORADIATION THERAPY FOR ANAL CANCER: RELATIONSHIP AND PREDICTIVE CAPABILITIES

• Published in: Cardiometry no. 29; pp. 38 - 39
• Main Authors: Zykova, T A, Gusareva, M A, Shevyakova, E A, Frantsiyants, E M, Tolmacheva, E A, Zinkovich, M S, Kosheleva, N G, Solntseva, A A
• Format: Journal Article
• Language: English
• Published: Moscow Russian New University 01.11.2023
• Subjects: Anal cancer; Cancer therapies; Human papillomavirus; Medical prognosis
• ISSN: 2304-7232
• DOI: 10.18137/cardiometry.2023.29.conf.30

Introduction: The effectiveness of chemoradiation therapy (CRT) is conventionally assessed in terms of achieving clinical complete response (CCR), overall and event-free survival. Anal cancer (AR) is considered as one of the cancer diseases with a proven etiological agent: the human papillomavirus (HPV). The search for biomarkers to predict the effectiveness of CRT is always relevant, and an assessment of virological response (VR) maybe useful for this purpose. Aim: To compare rates of clinical complete response (CCR) and virological response (VR) to CRT for anal cancer. Material and methods: 35 patients with squamous cell AR were examined, inel. 31 females (57.1±8.8 years) and 4 males (55±9.5 years). There were HPV+ detected in 28 (80%) and HPV in 7 (20%) patients. All patients received radical CRT and underwent treatment without interruption with moderate radiation reactions. Antiviral therapy was not administered. Smears from the surface of the tumor were taken before CRT, on the day of its completion, and 3, 6, 9 and 12 months after CRT. To determine HPV DNA, the AmpliSens® HPV HCR genotype-titer-FL kit was used. The presence of CCR at 6 months and 3-year overall and event-free survival rates were compared. We assessed rapid virological response (RVR - sustained disappearance or reduction of HPV DNA by more than 2 1g at the end of CRT course), slow virological response (SVR - sustained disappearance of HPV DNA at 6 months after CRT), virological load fluctuation or reappearance (VRA - reappearance of HPV DNA) and lack of virological response (LVR). All patients were divided into two groups: those with the presence of stable VR (group 1 - with RVR and SVR) and the patients without sustainable VR (group 2 - with LVR and VRA). Statistical data processing was carried out using Microsoft Office Excel and Statistica 10.0. To compare the qualitative characteristics of the samples, Fisher's exact test was used. Differences were considered statistically significant at p <0.05. Results: CCR was achieved in 6 HPV patients (85.7%) and in 20 HPV+ patients (71.4%) (p>0.05). The 3-year overall and event-free survival rates did not depend on the HPV status. RVR developed in 13 HPV+ patients (46.4%), SVR was detected in 4 patients (14.3%), VRA was revealed in 5 patients (17.9%), and LVR was recorded in 6 patients (21.4%). When assessing CCR, a significant difference was obtained between RVR and LVR (84.6% vs 33.3%, p=0.046). The difference in the incidence rate of CCR when comparing SVR and LVR tended to be significant (100% vs 33.3%, p = 0.071). In the patients with RVR, a 3-year event-free survival was higher than in all others (91.7% vs 53.8%, p = 0.035) as against the patients with VRA (91.7% vs 25%, p = 0.027) and the patients with LVR (91.7% vs 40.0%, p=0.053). Among the HPV+ patients, CCR was achieved in 15 individuals (88.2%) of group 1 and in 5 individuals (45.5%) of group 2 (p=0.022); a 3-year overall survival was recorded to be 16 (94.1%) in group 1 and 9 (81.8%) in group 2 (p>0.05), and an event-free survival was reported to be 15 (88.3%) and 3 (27 .3%, p=0.0018), respectively. That is, the best rates of CCR and the event-free survival were achieved in the patients with stable VR. With VRA, the rates both of the overall and the event-free 3-year survival were however not statistically significant, but lower than in case of the complete absence of VR. VRA was reported before the recurrence. In two of the five patients, VRA occurred 3 months after CRT, and 6 months later they underwent surgery. In three patients, VRA occurred 6 months after CRT; in one of them, a relapse was detected 9 months after CRT; in another one it was revealed 18 months after CRT. Apparently, VRA occurs earlier than the recurrence develops, and, therefore, its detection may allow identifying earlier a negative response to CRT and adjusting the treatment. Conclusions: Patients with VR more often achieve CCR and have a higher 3-year event-free survival. When assessing the prognosis of the effectiveness of CRT, it is advisable to take into account the stable VR and evaluate it simultaneously with the assessment of the CCR.