The Role of Multiparametric Magnetic Resonance in Volumetric Modulated Arc Radiation Therapy Planning for Prostate Cancer Recurrence After Radical Prostatectomy: A Pilot Study

Quantitative ADC: An Additional Tool in the Evaluation of Prostate Cancer?

Prostate cancer is one of the most common tumors among the male population. Magnetic resonance imaging (MRI), standardized by the PI-RADS version 2.1 scoring system, has a fundamental role in detecting prostate cancer and evaluating its aggressiveness. Diffusion-weighted imaging sequences and apparent diffusion coefficient values, in particular, are considered fundamental for the detection and characterization of lesions. In 2016 the International Society of Urological Pathology introduced a new anatomopathological 5-grade scoring system for prostate cancer. The aim of this study is to evaluate the correlation between quantitative apparent diffusion coefficient values (ADC) derived from diffusion-weighted imaging (DWI) sequences and the International Society of Urological Pathology (ISUP) and PI-RADS groups. Our retrospective study included 143 patients with 154 suspicious lesions, observed on prostate magnetic resonance imaging and compared with the histological results of the biopsy. We observed that ADC values can aid in discriminating between not clinically significant (ISUP 1) and clinically significant (ISUP 2-5) prostate cancers. In fact, ADC values were lower in ISUP 5 lesions than in negative lesions. We also found a correlation between ADC values and PI-RADS groups; we noted lower ADC values in the PI-RADS 5 and PI-RADS 4 groups than in the PI-RADS 3 group. In conclusion, quantitative apparent diffusion coefficient values can be useful to assess the aggressiveness of prostate cancer.

Linac-based stereotactic salvage reirradiation for intraprostatic prostate cancer recurrence: toxicity and outcomes

BACKGROUND

The rates of local failure after curative radiotherapy for prostate cancer (PC) remain high despite more accurate locoregional treatments available, with one third of patients experiencing biochemical failure and clinical relapse occurring in 30-47% of cases. Today, androgen deprivation therapy (ADT) is the treatment of choice in this setting, but with not negligible toxicity and low effects on local disease. Therefore, the treatment of intraprostatic PC recurrence represents a challenge for radiation oncologists. Prostate reirradiation (Re-I) might be a therapeutic possibility. We present our series of patients treated with salvage stereotactic Re‑I for intraprostatic recurrence of PC after radical radiotherapy, with the aim of evaluating feasibility and safety of linac-based prostate Re‑I.

MATERIALS AND METHODS

We retrospectively evaluated toxicities and outcomes of patients who underwent salvage reirradiation using volumetric modulated arc therapy (VMAT) for intraprostatic PC recurrence. Inclusion criteria were age ≥ 18 years, histologically proven diagnosis of PC, salvage Re‑I for intraprostatic recurrence after primary radiotherapy for PC with curative intent, concurrent/adjuvant ADT with stereotactic body radiation therapy (SBRT) allowed, performance status ECOG 0-2, restaging choline/PSMA-PET/TC and prostate MRI after biochemical recurrence, and signed informed consent.

RESULTS

From January 2019 to April 2022, 20 patients were recruited. Median follow-up was 26.7 months (range 7-50). After SBRT, no patients were lost at follow-up and all are still alive. One- and 2‑year progression free survival (PFS) was 100% and 81.5%, respectively, while 2‑year biochemical progression-free survival (bFFS) was 88.9%. Four patients (20%) experienced locoregional lymph node progression and were treated with a further course of SBRT. Prostate reirradiation allowed the ADT start to be postponed for 12-39 months. Re‑I was well tolerated by all patients and none discontinued the treatment. No cases of ≥ G3 genitourinary (GU) or gastrointestinal (GI) toxicity were reported. Seven (35%) and 2 (10%) patients experienced acute G1 and G2 GU toxicity, respectively. Late GU toxicity was recorded in 10 (50%) patients, including 8 (40%) G1 and 2 (10%) G2. ADT-related side effects were found in 7 patients (hot flashes and asthenia).

CONCLUSION

Linac-based SBRT is a safe technique for performing Re‑I for intraprostatic recurrence after primary curative radiotherapy for PC. Future prospective, randomized studies are desirable to better understand the effectiveness of reirradiation and the still open questions in this field.

Diagnosis of SARS-CoV-2 during the Pandemic by Multiplex RT-rPCR hCoV Test: Future Perspectives

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has rapidly become a significant threat to public health. However, among the Coronaviridae family members, there are other viruses that can also cause infections in humans. Among these, severe acute respiratory syndrome (SARS-CoV) and Middle East respiratory syndrome (MERS-CoV) have posed significant threats to human health in the past. Other human pathogenic coronaviruses have been identified, and they are known to cause respiratory diseases with manifestations ranging from mild to severe. In this study, we evaluated the performance of a multiplex RT-rPCR specific to seven human pathogenic coronaviruses in mainly detecting SARS-CoV-2 directly from nasopharyngeal swabs obtained from suspected COVID-19 infected patients, while simultaneously detecting different human pathogenic coronaviruses in case these were also present. We tested 1195 clinical samples suspected of COVID-19 infection. The assay identified that 69% of the samples tested positive for SARS-CoV-2 (1195), which was confirmed using another SARS-CoV-2 RT-PCR kit available in our laboratory. None of these clinical samples were positive for SARS-CoV, MERS-CoV or HCoV. This means that during the endemic phase of COVID-19, infection with other human pathogenic coronaviruses, even the common cold coronavirus (HCoV), is very uncommon. Our study also confirmed that the multiplex RT-rPCR is a sensitive assay for detecting SARS-CoV-2 regardless of differences among the variants. This multiplex RT-rPCR is also time- and cost-saving and very easy to apply in the diagnostic laboratory due to its simple procedure and its stability in storage after preparation. These features make the assay a valuable approach in screening procedures for the rapid detection of SARS-CoV-2 and other human pathogenic coronaviruses that could affect public health.

First Experience and Prospective Evaluation on Feasibility and Acute Toxicity of Online Adaptive Radiotherapy of the Prostate Bed as Salvage Treatment in Patients with Biochemically Recurrent Prostate Cancer on a 1.5T MR-Linac

Introduction: Novel MRI-linear accelerator hybrids (MR-Linacs, MRL) promise an optimization of radiotherapy (RT) through daily MRI imaging with enhanced soft tissue contrast and plan adaptation on the anatomy of the day. These features might potentially improve salvage RT of prostate cancer (SRT), where the clinical target volume is confined by the mobile organs at risk (OAR) rectum and bladder. So far, no data exist about the feasibility of the MRL technology for SRT. In this study, we prospectively examined patients treated with SRT on a 1.5 T MRL and report on workflow, feasibility and acute toxicity. Patients and Methods: Sixteen patients were prospectively enrolled within the MRL-01 study (NCT: NCT04172753). All patients were staged and had an indication for SRT after radical prostatectomy according to national guidelines. RT consisted of 66 Gy in 33 fractions or 66.5/70 Gy in 35 fractions in case of a defined high-risk region. On the 1.5 T MRL, daily plan adaption was performed using one of two workflows: adapt to shape (ATS, using contour adaptation and replanning) or adapt to position (ATP, rigid replanning onto the online anatomy with virtual couch shift). Duration of treatment steps, choice of workflow and treatment failure were recorded for each fraction of each patient. Patient-reported questionnaires about patient comfort were evaluated as well as extensive reporting of acute toxicity (patient reported and clinician scored). Results: A total of 524/554 (94.6%) of fractions were successfully treated on the MRL. No patient-sided treatment failures occurred. In total, ATP was chosen in 45.7% and ATS in 54.3% of fractions. In eight cases, ATP was performed on top of the initial ATS workflow. Mean (range) duration of all fractions (on-table time until end of treatment) was 25.1 (17.6–44.8) minutes. Mean duration of the ATP workflow was 20.60 (17.6–25.2) minutes and of the ATS workflow 31.3 (28.2–34.1) minutes. Patient-reported treatment experience questionnaires revealed high rates of tolerability of the treatment procedure. Acute toxicity (RTOG, CTC as well as patient-reported CTC, IPSS and ICIQ) during RT and 3 months after was mild to moderate with a tendency of recovery to baseline levels at 3 months post RT. No G3+ toxicity was scored for any item. Conclusions: In this first report on SRT of prostate cancer patients on a 1.5 T MRL, we could demonstrate the feasibility of both available workflows. Daily MR-guided adaptive SRT of mean 25.1 min per fraction was well tolerated in this pretreated collective, and we report low rates of acute toxicity for this treatment. This study suggests that SRT on a 1.5 T MRL can be performed in clinical routine and it serves as a benchmark for future analyses.

Targeting Local Recurrence After Surgery With MRI Imaging for Prostate Cancer in the Setting of Salvage Radiation Therapy

Magnetic resonance imaging (MRI) is being increasingly used for imaging suspected recurrence in prostate cancer therapy. Functional MRI with diffusion and perfusion imaging has the potential to demonstrate local recurrence even at low PSA value. Detection of recurrence can modify the management of postprostatectomy biochemical recurrence. MRI scan acquired before salvage radiotherapy is useful for the localization of recurrent tumors and also in the delineation of the target volume. The objective of this review is to assess the role and potential impact of MRI in targeting local recurrence after surgery for prostate cancer in the setting of salvage radiation therapy.