Retrospective Analysis of Clinical Outcomes of Stereotactic Body Radiation Therapy for Localized Prostate Cancer at an Asian Cancer Specialist Centre.

INTRODUCTION: The current treatment options for localized prostate cancer are radical prostatectomy and external beam radiotherapy (EBRT) with stereotactic body radiation therapy (SBRT) gaining interest as a treatment option compared to standard fractionation radiation therapy. This present study is a retrospective study evaluating the correlations between the biochemical efficacy, and treatment toxicity in SBRT for localized prostate cancer. METHODS: All organ-confined prostate cancer patients treated with SBRT from 2010 to 2018, at Beacon Hospital, Malaysia were included in this study. Patient demographics, dosimetric parameters, and disease information were retrospectively collected. The primary endpoint was biochemical recurrence-free survival assessed using the Phoenix definition (Nadir + 2 ng/mL). Toxicity outcomes were scored using the Radiation Therapy Oncology Group scale. RESULTS: Fourty-nine patients who met the inclusion criteria (5 low-, 13 intermediate- and 31 high-risk according to the D'amico Risk Classification) received SBRT. The most common dose regime was 34-35Gy in 5 fractions (n=18). Other dose regimes were 24Gy in 3 fractions and 25-33Gy in 5 fractions. Median follow-up was 45.4 months. The median pre-treatment prostate-specific antigen (PSA) was 11.22 ng/mL, which decreased to a median PSA of 0.1 ng/mL by 2 years post-treatment. Out of the 49 cases, only 1 case of biochemical recurrence occurred, yielding a 3- and 5-year overall survival of 100%, and a 3- and 5- year biochemical recurrence-free rate of 100% and 95.2%. Acute grade III urinary toxicities occurred in 1 (2%); whereas acute grade I urinary and rectal toxicities were seen in 22 (44.9%) and 7 (14.3%) patients respectively. Grade I and grade III late rectal toxicities occurred in 3 and 1 patients respectively, while 3 and 1 patient reported late grade I and III urethral stricture respectively. CONCLUSION: SBRT for clinically-localized and locally advanced prostate cancer provided promising outcomes with low toxicity and good biochemical control.

The role of heat shock proteins and glucose regulated proteins in cancer

Heat shock proteins (HSPs) are a family of evolutionary conserved proteins that work as molecular chaperones for cellular proteins essential for cell viability and growth as well as having numerous cyto-protective roles. They are sub-categorised based on their molecular weights; amongst which some of the most extensively studied are the HSP90 and HSP70 families. Important members of these two families; Heat shock proteins 70 and heat shock proteins 90 (Hsp70/90), are the glucose regulated proteins (GRP). These stress-inducible chaperones possess distinct roles from that of the other HSPs, residing mostly in the endoplasmic reticulum and mitochondria, but they can also be translocated to other cellular locations. Their ability in adapting to stress conditions in the tumour microenvironment suggests novel functions in cancer. GRPs have been implicated in many crucial steps of carcinogenesis to include stabilization of oncogenic proteins, induction of tumour angiogenesis, inhibition of apoptosis and replicative senescence, and promotion of invasion and metastasis.