On the probability of lymph node negativity in pN0-staged prostate cancer-a theoretically derived rule of thumb for adjuvant needs.

PURPOSE: The extent of lymphadenectomy and clinical features influence the risk of occult nodes in node-negative prostate cancer. We derived a simple estimation model for the negative predictive value (npv) of histopathologically node-negative prostate cancer patients (pN0) to guide adjuvant treatment. METHODS: Approximations of sensitivities in detecting lymph node metastasis from current publications depending on the number of removed lymph nodes were used for a theoretical deduction of a simplified formulation of npv assuming a false node positivity of 0. RESULTS: A theoretical formula of npv = p(N0IpN0) = (100 - prevalence) / (100 - sensitivityâ€¯× prevalence) was calculated (sensitivity and preoperative prevalence in %). Depending on the number of removed lymph nodes (nLN), the sensitivity of pN0-staged prostate cancer was derived for three sensitivity levels accordingly: sensitivity = f(nLN) = 9â€¯× nLN /100 for 0 ≤ nLN ≤ 8 and f(nLN) = (nLN + 70) /100 for 9 ≤ nLN ≤ 29 and f(nLN) = 1 for nLN ≥ 30. CONCLUSION: We developed a theoretical formula for estimation of the npv in pN0-staged prostate cancer patients. It is a sine qua non to use the formula in a clinically experienced context before deciding to electively irradiate pelvic lymph nodes or to intensify adjuvant systemic treatment.

MHC gene copy number variation in Tasmanian devils: implications for the spread of a contagious cancer.

Tasmanian devils face extinction owing to the emergence of a contagious cancer. Devil facial tumour disease (DFTD) is a clonal cancer spread owing to a lack of major histocompatibility complex (MHC) barriers in Tasmanian devil populations. We present a comprehensive screen of MHC diversity in devils and identify 25 MHC types and 53 novel sequences, but conclude that overall levels of MHC diversity at the sequence level are low. The majority of MHC Class I variation can be explained by allelic copy number variation with two to seven sequence variants identified per individual. MHC sequences are divided into two distinct groups based on sequence similarity. DFTD cells and most devils have sequences from both groups. Twenty per cent of individuals have a restricted MHC repertoire and contain only group I or only group II sequences. Counterintuitively, we postulate that the immune system of individuals with a restricted MHC repertoire may recognize foreign MHC antigens on the surface of the DFTD cell. The implication of these results for management of DFTD and this endangered species are discussed.

Intention-to-Treat Analysis of 68Ga-PSMA and 11C-Choline PET/CT Versus CT for Prostate Cancer Recurrence After Surgery.

Biochemical recurrence (BCR) after prostate cancer surgery is common, even after additional salvage radiotherapy. BCR might be explained by target miss. Improved diagnostic accuracy provided by PET could potentially circumvent this therapeutic gap. Therefore, we evaluated consecutive 68Ga-prostate-specific membrane antigen (PSMA) PET/CT, 11C-choline PET/CT, and standard CT imaging in the same patient with regard to TNM-stage migration and accordingly adapted curative radiotherapy options including ablative treatment of oligometastases (n ≤ 5). The cost efficacy of PET- versus CT-based treatment was also calculated. Methods: The prospective register database (064/2013BO1) was retrospectively searched for patients fulfilling the following 3 inclusion criteria: BCR after radical prostatectomy (pT2-pT4 pN0-pN1 cM0, postoperative radiotherapy allowed); 11C-choline PET/CT, 68Ga-PSMA PET/CT, and diagnostic CT performed within 24 h; and available clinical data. Ten treatment routines were defined according to current practice. Furthermore, intention-to-treat and treatment-related costs depending on the shift of TNM stage after imaging were analyzed. Eighty-three patients were eligible (median prostate-specific antigen level, 1.9 ng/mL). Results: Both PET examinations led to concordant results in 72% of patients, whereas the concordance of TNM staging between 68Ga-PSMA PET and diagnostic CT was only 36%. Incorrect staging would lead to "wrong" treatment and therefore to additional costs. A 68Ga-PSMA PET study would be cost-effective if additional costs do not exceed €3,844 ($4,312) (vs. CT). The number needed to image was 2 (for CT) and 4 (for 11C-choline PET) to avoid 1 incorrect treatment. In addition, 68Ga-PSMA PET staging enabled new curative options in half the patients with previous radiotherapy who otherwise receive palliative androgen deprivation therapy. Conclusion:68Ga-PSMA PET/CT is cost-effective in all patients with regard to avoidance of incorrect treatment. It enabled new curative options for patients with previous radiotherapy who are usually treated palliatively. Therefore, 68Ga-PSMA PET/CT staging should become standard for BCR after surgery with or without radiotherapy.

MATLAB®-based fitting method to evaluate survival fractions after multimodal treatment.

To easily analyse and visualize cell kill dynamics measured by survival fraction after single or combined treatments a MATLAB®-based application was developed. A statistical analysis with different options of visualisation of single and combined treatment effects can be performed in a few steps not requiring advanced knowledge of statistical programs.