Ozan Cem Guler

The feasibility of prostate-specific membrane antigen positron emission tomography(PSMA PET/CT)-guided radiotherapy in oligometastatic prostate cancer patients

AbstractBackgroundTo investigate the efficacy and toxicity of 68Ga-PSMA-HBED-CC (68Ga-PSMA) PET-CT-guided RT in the treatment ofn oligometastatic prostate cancer retrospectively.MethodsA total of 23 prostate cancer patients with biochemical relapse, of which 13 were castration sensitive (CS) and 10 castration resistant (CR), were treated with intensity-modulated and image-guided RT (IMRT-IGRT) on ≤3 metastases detected by 68Ga PSMA PET-CT. Androgen deprivation therapy was continued in CR patients.ResultsA total of 38 metastases were treated. The involved sites were pelvic bone (nxa0=xa016), pelvic lymph nodes (nxa0=xa011), paraaortic lymph nodes (nxa0=xa06), ribs (nxa0=xa03) and vertebral body (nxa0=xa02). The median PSA prior to RT was 1.1xa0ng/mL (range 0.1–29.0xa0ng/mL). A median dose of 43.5xa0Gy (range 30–64xa0Gy) was delivered by IMRT-IGRT in 12–27 fractions. At a median follow-up of 7xa0months (range 2–17xa0months), 19 patients (83%) were in remission. Four patients (17%) developed distant recurrences. The actuarial 1-year LC, PFS and OS rates were 100, 51 (95% CI 8–83%) and 100%. Univariate analysis demonstrated a statistically significantly better PFS in CS patients as compared to CR patients (1-year PFS 67 vs. 0%, pxa0<xa00.01). One patient experienced grade 2 acute gastrointestinal toxicity. Grade 3 or more toxicity events were not observed.ConclusionsBy providing optimal LC, low toxicity and a promising PFS in CS patients, the current retrospective study illustrated that 68Ga PSMA PET-CT-guided RT may be an attractive treatment strategy in patients with oligometastatic prostate cancer. Validation by randomized trials is eagerly awaited.

Prognostic values of ADCmean and SUVmax of the primary tumour in cervical cancer patients treated with definitive chemoradiotherapy

Abstract We analysed the correlation of 18F-fluorodeoxyglucose uptake into primary tumours using the maximum standardised uptake value (SUVmax) and the mean apparent diffusion coefficient (ADCmean) values in magnetic resonance imaging (MRI) with the clinical and pathological factors in patients with cervical cancer who were treated with concurrent chemoradiotherapy. The patients were stratified according to the primary tumour pre-treatment ADCmean and SUVmax cut-off values. There were significant correlations between the SUVmax of the primary tumour and tumour size, and the treatment response. The correlation between the ADCmean and FIGO stage, tumour size, and the lymph node metastasis was significant. The SUVmax was significantly and inversely correlated with the ADCmean for cervical cancer (ru2009=u2009−0.44, pu2009<.001). In the multivariate analysis, the primary tumour ADCmean, treatment response and the lymph node metastasis emerged as significant independent predictors of both OS and DFS, and of the primary tumour SUVmax for DFS. Tumour size has a borderline significance for OS. High SUVmax and low ADCmean of the primary tumour are important predictive factors for identifying high-risk patients with cervical cancer who are treated with definitive chemoradiotherapy. These results point to a future role for the diffusion-weighted MRI and for 18F-fluorodeoxyglucose positron emission tomography, not only in the staging of cervical cancer but as an aid in the selection of an adjuvant treatment regimen after chemoradiotherapy for individual patients. Impact statement What is already known on this subject? A negative correlation between primary tumour SUVmax derived from positron emission tomography (PET/CT) and ADCmin derived from diffusion weighted magnetic resonance imaging (DW-MRI) in various cancer types and cervical cancer has been demonstrated. However, the prognostic value of primary tumour SUVmax and ADCmean in cervical cancer patients treated with definitive chemoradiotherapy is not well studied yet. What the results of this study add? The patients with high-risk features (larger tumours, extensive stage, lymph node metastasis) had higher primary tumour SUVmax and lower ADCmean values. Primary tumour ADCmean and lymph node metastasis emerged as significant independent predictors of both overall and disease-free survival. This study demonstrated that the functional biomarkers delivered from PET-CT and DW-MRI are important in predicting the treatment outcomes in the squamous cell carcinoma of cervix treated with definitive chemoradiotherapy, where clinical and radiological findings are very important, since these patients are not staged surgically. What are the implications of these findings for clinical practice and/or further research? Based on these findings, there may be a future role of DW-MRI and FDG/PET-CT not only in the staging of cervical cancer but as an aid in the selection of an adjuvant treatment regimen after chemoradiotherapy (ChRT) for individual patients.

Radiotherapy in the management of classic Kaposi's sarcoma: A single institution experience from Northeast Turkey

Kaposi sarcoma is a rare adult neoplasm and there has been no certain consensus on standard treatment, either local or systemic. Radiotherapy is an effective, suitable treatment modality. Between 1996 and 2016, patients who were diagnosed with Kaposi sarcoma and referred to our clinic for radiotherapy were included in this retrospective study. Ninety‐two patients were examined in total and it was diagnosed that all the patients had non‐HIV associated Kaposis sarcoma. There were 36 (39%) females and 56 (61%) males and female to male ratio was 2/3. Median age at presentation was 72 (30–93) years. Sixty‐eight patients (77%) were treated with 8 Gy (1 fraction), 15 patients (16%) were treated with 20 Gy (2 Gy/fraction), four patients (4%) were treated 25 Gy (2.5 Gy/fraction), and five patients (6%) were treated 30 Gy (3 Gy/fraction). The median follow‐up time was 72 (5–192) months. The complete response at 5 years was 91.6% with >20 Gy and 89.6% with 8 Gy. Radiotherapy is an effective, suitable treatment modality of Classic Kaposi sarcoma and usually, radiotherapy is well tolerated with minimal side effects.

Advanced Radiotherapy Techniques in Prostate Cancer

Prostate cancer (PC) is the most common tumor in males. Treatment options for localized prostate cancer include radical prostatectomy and radiation therapy (RT), which is delivered either as external beam radiation therapy (EBRT) or brachytherapy (BRT). According to “European Association of Urology” guidelines, although radical prostatectomy is the gold standard treatment option in localized PC, definitive RT could be an alternative treatment option in medically inoperable patients or who refused surgery. Treatment of PC has been evolving since the last decades with the innovation in technology. More precise radiotherapy (RT) techniques provides sharper isodoses while sparing organs at risk (OAR). It is also important that setup margins could be reduced with image guidance. Hence, precisely defining targets and considering organ movement are gaining much more importance. As a consequence of sharper isodoses and image guidance, dose escalation comes into question. It is well known that there is a positive correlation between RT dose and biochemical progression-free survival (BPFS) but not overall survival (OS) rates, with dose escalated conventionally fractionated up to 76–80 Gy in 2 Gy fractions, which is a biologically equivalent dose (BED1.5) of 180–200 Gy, assuming an α/β of 1.5. A recent meta-analysis clearly demonstrated an increased disease control with a BED1.5 to 200 Gy, with no additional clinical benefit with doses above 200 Gy. In order to deliver higher doses to the prostate without increasing surrounding organs at risk, it is essential to delineate target volumes properly, deliver RT with high-technology devices, immobilize patient, and track prostate during RT. The aim of this chapter is to review recent advances in prostate RT.

Bladder Preservation Therapies in Bladder Cancer

Intravesical therapies with close monitoring are adequate for superficial disease, and chemotherapy and palliative radiotherapy are the main treatment options in metastatic stages. For muscle-invasive disease, treatment strategies are basically divided into two groups: surgery vs. trimodality treatment (TMT) that involves transurethral resection (TUR) of tumor tissues and concurrent radiochemotherapy (RCT); radiotherapy (RT) monotherapy is not recommended as primary curative option, and multimodality treatment is currently regarded only as an alternative in selected, well-informed, and compliant patients in whom cystectomy is not considered for clinical or personal reasons.