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(SBRT) for prostate cancer in men with large prostates, >50 cm3

hopeful and opt...
Posts: 2218
Joined: Apr 2009

Background: Patients with large prostate volumes have been shown to have higher rates of genitourinary and gastrointestinal toxicities after conventional radiation therapy for prostate cancer.

The efficacy and toxicity of stereotactic body radiation therapy (SBRT), which delivers fewer high-dose fractions of radiation treatment, is unknown for large prostate volume prostate cancer patients. We report our early experience using SBRT for localized prostate cancer in patients with large prostate volumes.

Methods: 57 patients with prostate volumes ≥ cm3 prior to treatment with SBRT for localized prostate carcinoma and with a minimum follow up of two years were included in this retrospective review of prospectively collected data. Treatment was delivered using Cyberknife (Accuray) with doses of 35-36.25 Gy in 5 fractions. Biochemical control was assessed using the Phoenix definition. Toxicities were scored using the CTCAE v.4. Quality of life was assessed using the American Urological Association (AUA) Symptom Score and the Expanded Prostate Cancer Index Composite (EPIC)-26.

Results: 57 patients (23 low-, 25 intermediate- and 9 high-risk according to the D¿Amico classification) at a median age of 69 years (range, 54-83 years) received SBRT with a median follow-up of 2.9 years. The median prostate size was 62.9 cm3 (range 50-138.7 cm3). 33.3% of patients received ADT. The median pre-treatment prostate-specific antigen (PSA) was 6.5 ng/ml and decreased to a median PSA of 0.4 ng/ml by 2 years (p < 0.0001). A mean baseline AUA symptom score of 7.5 significantly increased to 13 at 1 month (p =0.001) and returned to baseline by 3 months (p =0.21). 23% of patients experienced a late transient urinary symptom flare in the first two years following treatment. Mean baseline EPIC bowel scores of 95.8 decreased to 78.1 at 1 month (p < 0.0001), but subsequently improved to 93.5 three months (p =0.08). The 2-year actuarial incidence rates of GU and GI toxicity ≥ grade 2 were 49.1% and 1.8%, respectively. Two patients (3.5%) experienced grade 3 urinary toxicity, and no patient experienced grade 3 gastrointestinal toxicity.

Conclusions: SBRT for clinically localized prostate cancer was well tolerated in men with large prostate volumes.

Written by: 
Janowski E, Chen LN, Kim JS, Lei S, Suy S, Collins B, Lynch J, Dritschilo A, Sean C.   Are you the author? 
Department of Radiation Medicine, Georgetown University Hospital, Washington DC 20007, USA.

 

Reference: Radiat Oncol. 2014 Nov 15;9(1):241. 
doi: 10.1186/s13014-014-0241-3

PubMed Abstract
PMID: 25398516

UroToday.com Prostate Cancer Section

choclabs
Posts: 23
Joined: Feb 2016

Integral dose: Comparison between four techniques for prostate radiotherapy - Abstract

AIM: Comparisons of integral dose delivered to the treatment planning volume and to the whole patient body during stereotactic, helical and intensity modulated radiotherapy of prostate.

BACKGROUND: Multifield techniques produce large volumes of low dose inside the patient body. Delivered dose could be the result of the cytotoxic injuries of the cells even away from the treatment field. We calculated the total dose absorbed in the patient body for four radiotherapy techniques to investigate whether some methods have a potential to reduce the exposure to the patient.

MATERIALS AND METHODS: We analyzed CyberKnife plans for 10 patients with localized prostate cancer. Five alternative plans for each patient were calculated with the VMAT, IMRT and TomoTherapy techniques. Alternative dose distributions were calculated to achieve the same coverage for PTV. Integral Dose formula was used to calculate the total dose delivered to the PTV and whole patient body.

RESULTS: Analysis showed that the same amount of dose was deposited to the treated volume despite different methods of treatment delivery. The mean values of total dose delivered to the whole patient body differed significantly for each treatment technique. The highest integral dose in the patient's body was at the TomoTherapy and CyberKnife treatment session. VMAT was characterized by the lowest integral dose deposited in the patient body.

CONCLUSIONS: The highest total dose absorbed in normal tissue was observed with the use of a robotic radiosurgery system and TomoTherapy. These results demonstrate that the exposure of healthy tissue is a dosimetric factor which differentiates the dose delivery methods.

Written by:
Ślosarek K, Osewski W, Grządziel A, Radwan M, Dolla Ł, Szlag M, Stąpór-Fudzińska M.   Are you the author?
MSC Memorial Cancer Center and Institute of Oncology Gliwice Branch, Department of Radiotherapy and Brachytherapy Planning, ul. Wybrzeża Armii Krajowej 15, 44-101 Gliwice, Poland.

Reference: Rep Pract Oncol Radiother. 2014 Nov 18;20(2):99-103.
doi: 10.1016/j.rpor.2014.10.010

Max Former Hodgkins Stage 3's picture
Max Former Hodg...
Posts: 3250
Joined: May 2012

Michael,

What all studies agree on regarding fractionated radiation vs. SBRT is that they have exactly equal curative rates.

SBRT has an advantage of convenience.  While the report you quote makes intuitive sense, this battle will not be resolved for decades. My doctor recommended IGRT over SBRT, but again, this is a Ford-Chevy debate that will persist for many years into the future.

A major study last year, the biggest in history, reviewed ALL of the data regarding saturated fat and heart disease (run by Cambridge University, England).  Its conclusion ?  Saturated fat has NO (zero) effect on coronary heart disease. Not a small amount. NO:  NO EFFECT AT ALL. It was based upon 72 earlier stidies and over 600,000 patients.

It does not address the effects fat may have on cancer or obesity.

Studies come and studies are refuted. One has to use his own judgement, and keep his peace of mind.

http://www.cam.ac.uk/research/news/new-evidence-raises-questions-about-the-link-between-fatty-acids-and-heart-disease

.

choclabs
Posts: 23
Joined: Feb 2016

X-Ray or Gamma radiation is similar in that surrounding tissues gets dosed as well as entry path and exit path tissue. However proton energy is capable of being programmed to be delivered at a calculated speed so as to release the radiation energy at the tumor site and spare entry path and exit path radiation doses.

I do believe that attempting to measure doses of radiation recieved in the entire body minus the actual target tissue, is a worthwhile effort. It gives the patient and doctor data relevant enough for some concern.

I personally have a goal of 20 more years to live and seek to try and have my last 5-10 years in above average quality of life. Difficult to do if secondary cancer as a result of treatment becomes reality.

Thank you for posting your reply.

 

Max Former Hodgkins Stage 3's picture
Max Former Hodg...
Posts: 3250
Joined: May 2012

Michael,

I was trained in radiation health while in the Navy as a submariner.  It was not my primary field, which was weapons systems electronics, which had me working on warheads as well as around the reactor vessel.  I was also the ship's tritium monitoring officer (tritiated water is one of the forms of "heavy water"  [3H]).  It is mostly just a beta emitter, and mostly just an inhalation hazard.

My point is that I too am quite health and radiation conscious, which was a part of why I chose surgery over any form of radiation. This was augmented by my earlier lymphoma.  At 59 now, I hope to have some years remaining, but I have used at least three of those proverbial nine lives: besides lymphoma and PCa, I was run over by a car years ago. Eighteen fractures, two years of rehab.

Lymphoma chemo drugs, when mixed with radiation, are a known risk for developing leukemia, another concern that I had.  Of course this would not be relevant to most PCa patients undergoing RT in most cases. The radiation oncologist I cosidered using, when I ran this past him, said he considered it probably irrelevant, but I reasoned that no radiation had to be better than some.

max

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