With a high detectability rate and a low technical failure rate, measuring circulating tumour (ct)DNA was a useful response assessment in patients with anal cancer who were treated with chemoradiation (CRT). Further studies need to clarify whether patients can be stratified according to risk, and whether treatment de-escalation can be aligned with ctDNA measurements.
“The response evaluation in patients with anal cancer who underwent CRT is often delayed by 3–6 months,“ stated Dr Janet Alvarez (Memorial Sloan Kettering Cancer Center, NY, USA) . “Therefore, there is a strong need for an early response biomarker and ctDNA has demonstrated to be a promising candidate for this matter.” The retrospective study that was performed by Dr Alvarez and colleagues included 31 patients with non-metastatic anal squamous cell carcinoma who were treated with definitive-intent CRT.
In 23 of the 27 assessable patients, ctDNA was detected at baseline, corresponding to a detectability rate of 85%. In addition, 2 out of 4 patients in whom ctDNA was not detectable at baseline had excisional biopsies prior to baseline ctDNA measurement. According to Dr Alvarez, the technical failure rate was 3%. Furthermore, ctDNA was cleared within 21 days of treatment in 57% of the patients. In further detail, 73% of the patients with stage I or II disease cleared mid-treatment in a median of 30 days and 50% of the patients with stage III disease cleared mid-treatment in a median of 31 days. Next, in 96% of the patients, ctDNA was cleared by the end of treatment. Finally, ctDNA clearance appeared to precede a clinical complete response, which was observed in this group of patients in a median of 136 days.
In summary, ctDNA showed to be a useful biomarker to track responses in patients with anal cancer undergoing CRT, with ctDNA clearance preceding clinical complete response by approximately 100 days. Longer follow-up data and larger trials are needed to assess the clinical utility.
- Alvarez J, et al. Circulating tumor DNA (ctDNA) for response assessment in patients with anal cancer treated with definitive chemoradiation. Abstract 1, ASCO GI 2023, 19–21 January, San Francisco, CA, USA.
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Table of Contents: ASCO GI 2023
Letter from the Editor
ASCO GI 2023 Highlights Podcast
Oesophageal and Gastric Cancer
Zolbetuximab plus mFOLFOX6 successful in CLDN18.2-positive subgroup of gastric cancer
Regorafenib offers survival benefit for patients with pre-treated gastric cancer
Radiotherapy or not in locally advanced oesophageal or junctional cancer?
Neoadjuvant immunotherapy is safe and efficacious in a phase 2 gastric cancer trial
S-1 adjuvant chemotherapy: 4 or 8 courses in stage 2 gastric cancer?
LATG/LAPG demonstrates excellent long-term efficacy in stage 1 gastric cancer
3-year follow-up data confirms benefits of nivolumab plus chemotherapy
Long-term results for nivolumab plus chemotherapy and nivolumab plus ipilimumab in oesophageal cancer
Promising phase 2 results for HER-Vaxx in gastric cancer
Anal and Colorectal Cancer
IMbrave 151 missed primary endpoint in advanced BTC
Combination botensilimab plus balstilimab demonstrates promising activity in heavily pre-treated MSS CRC
Mutation-based selection to identify patients suitable for panitumumab treatment
Fucoidan associated with quality-of-life benefits in patients with rectal cancer receiving CCRT
ctDNA appears useful in monitoring patients with anal cancer undergoing CRT
SUNLIGHT trial meets primary endpoint in refractory metastatic CRC
Does cell-free DNA influence MRD testing in post-operative colon cancer?
OPERA: surgery may be avoided with adequate therapy in rectal cancer
Can we improve total neoadjuvant therapy for rectal cancer?
Palliative radiation therapy improves hepatic pain in HCC and liver metastasis
Improved survival following postoperative sorafenib plus TACE in HCC
Quality-of-life benefits for tislelizumab in uHCC
Stereotactic body radiation therapy beneficial for patients with locally advanced HCC
SWOG 1815, first-ever phase 3 trial in BTC, fails
Acceptable safety profile and encouraging efficacy of nanvuranlat in BTC
First-line NALIRIFOX superior to standard treatment in mPDAC
Novel approach delivers quality-of-life benefits for patients with pancreatic cancer