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• Chemoradiation suppression of active bone marrow shown in on-treatment FDG-PET. • No suppression shown in un-irradiation bone marrow. • Volumes of active bone marrow receiving 20 Gy are associated with blood count nadirs. To determine if suppression of active bone marrow, as defined on FDG PETCT, is seen in on-treatment imaging of anal cancer patients receiving concurrent chemoradiation. Scans from 26 patients participating in the ART trial (full title: Anal squamous cell carcinoma: Investigation of functional imaging during chemoRadioTherapy), a single center observational study with FDG PETCT prior to radiotherapy and at fraction 8–10 of concurrent chemoradiation were analysed. Active bone marrow was contoured in both the pelvis and un-irradiated thoracic spine. SUV and volume of active bone marrow after 8–10 fractions of treatment were compared to baseline. Dose metrics to pelvic active bone marrow were extracted and compared to reduction in SUV/active bone marrow volume and to blood count nadir using linear regression. Suppression of active bone marrow is seen in the pelvis by a reduction in mean SUV and volume of active bone marrow after 8–10 fractions of treatment. Suppression is not seen in un-irradiated thoracic spine. Dose metrics were associated with reduced SUV and reduced volume of active bone marrow. Volume of active bone marrow receiving <20 Gy was associated with WCC/ANC nadir. 20 Gy was identified as the most likely clinically meaningful dose threshold for toxicity. Volume of active bone marrow receiving <20 Gy correlated to WCC and ANC with an increase of 100 cc being associated with an increase of 0.4 and 0.3 respectively. The effect of concurrent chemoradiation in suppression of active bone marrow is seen in on-treatment FDG PETCT scans. Chemotherapy appears well tolerated after 2 weeks of treatment. [ABSTRACT FROM AUTHOR]

The article presents the study that investigates the vital role of early diagnosis in the management of early stage anal cancer. The topics discussed include the rising incidence of anal squamous cell carcinoma and the efficacy of radiotherapy and 5-fluorouracil and mitomycin chemotherapy as primary treatment.

Background and purpose A recent update of the RTOG 9811, reported differing relapse rates for early and late anal squamous cell carcinoma following chemoradiotherapy (CRT). There may be a role for dose-individualization, however the dose–response relationship for anal cancer is not currently known. Intensity-modulated radiotherapy (IMRT) has been widely adopted with multiple series published. The aim is to fit a tumor control probability (TCP) model to the published IMRT data. Materials and methods We performed a systematic review of PubMed and Embase databases to identify thirteen appropriate papers, including 625 patients. Predefined data fields were collected. A standard linear quadratic TCP model, which included repopulation, was fit by least squares minimization. Results The fitted TCP curve demonstrated a dose–response relationship with α = 0.196 Gy –1 . The curve suggests: in early stage tumours, a dose reduction from 50 Gy to 45 Gy reduces 2 year local control from 98% to 95%; in late stage tumours, a dose escalation from 50 Gy to 55 Gy improves the 2 year local control rate from approximately 50% to 80%. Conclusions The published data are broadly consistent with a linear quadratic dose–response model. Dose-individualization in anal cancer should be further investigated in the context of clinical trials. [ABSTRACT FROM AUTHOR]