Using the Roach Formula to Stratify Patients with Localised Prostate Cancer Treated with Intensity-modulated Radiotherapy

Full Article

MFT Chan, QYN Lam, VHF Lee, PPY Ho, HCK Sze, SWK Siu, PWK Kwong, TW Leung

Hong Kong J Radiol 2017;20:103-9

DOI: 10.12809/hkjr1715378

Objectives: The Roach formula can be used to calculate the risk of pelvic lymph node involvement in patients with prostate cancer. This study aimed to use the Roach formula to further differentiate high-risk patients at risk of treatment failure after intensity-modulated radiotherapy (IMRT), and to identify factors associated with biochemical failure-free survival (bFFS).

Methods: Records of consecutive patients with biopsy-proven localised prostate cancer (T1-4 N0M0) who underwent prostate-only IMRT between February 2006 and August 2011 were retrospectively reviewed. Neoadjuvant and concomitant androgen deprivation therapy (ADT) was given to intermediate- and high-risk patients, whereas adjuvant ADT was given to high-risk patients for 2 to 3 years if they could afford this self-financed item. Patients were divided into three groups of lymph node involvement based on the Roach formula (≤15%, >15-35%, and >35% risk) and their bFFS were compared. Factors associated with bFFS were identified using univariate and multivariate analyses.

Results: The median follow-up duration of 144 patients was 55.8 months. According to the National Institute for Health and Care Excellence classification, 6%, 30%, and 64% of patients were stratified as low, intermediate, and high risk, respectively. According to the Roach formula, 35%, 28%, and 37% of patients were stratified as low, (≤15%), intermediate (>15-35%), and high (>35%) risk of lymph node involvement, respectively. Biochemical failure occurred in 23 patients. The median bFFS was 48.5 months. The 5-year bFFS in the three groups of ≤15%, >15-35%, and >35% risk of lymph node involvement based on the Roach formula were 100%, 87.7%, and 75.4%, respectively (p = 0.003). In multivariate analysis, significant factors associated with better bFFS were patient age of >75 years, pretreatment serum prostate-specific antigen (PSA) of ≤20 ng/ml, undetectable serum PSA after IMRT, and longer duration of adjuvant ADT.

Conclusion: The Roach formula can further differentiate patients at higher risk (>15-35% and >35%) of lymph node involvement to receive more intensified IMRT and closer monitoring to improve their bFFS.


Authors’ affiliations:
MFT Chan, QYN Lam, PPY Ho, SWK Siu, PWK Kwong, TW Leung: Department of Clinical Oncology, Queen Mary Hospital, Pokfulam, Hong Kong
VHF Lee, HCK Sze: Department of Clinical Oncology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong








方法:回顧2006年2月至2011年8月所有接受前列腺IMRT的局部前列腺癌(T1-4 N0M0)患者。中高危患者被給予新輔助治療和抗雄激素治療(ADT),而高危患者(如能負擔)被給予2至3年輔助ADT。根據Roach公式,患者被分為三級淋巴結受累風險(≤15%、>15-35%、>35%),並比較其bFFS。與bFFS的相關因素用單變量和多變量分析來確定。

結果:共144例的中位隨診時間為55.8個月。根據NICE分類,6%、30%、64%的患者被分為低、中、高危。根據Roach公式,35%、28%、37%的患者被分為低(≤15%)、中(>15-35%)、高 (>35%)淋巴結受累風險。23例患者生化失敗。bFFS中位數為48.5個月。基於Roach公式的≤15%、>15-35%、>35%的淋巴結受累風險,其bFFS分別為100%、87.7%、75.4%(p = 0.003)。在多變量分析中,與更佳bFFS的相關因素為患者年齡大於75歲、療前血清前列腺抗原(PSA)≤20 ng/ml、IMRT後血清PSA降低至檢測不到、及接受輔助ADT治療時間較長。