Hypofractionated Versus Conventional Fractionation External Beam Radiotherapy in Intermediate and High Risk Localized Prostate Cancer

Abstract

Abstract Background: The treatment options of intermediate and high risk prostate cancer include radical prostatectomy, radiotherapy, and androgen deprivation therapy. Hypofractionated radiotherapy is becoming more popular lately due to better understanding of the radiobiology of prostate cancer and favorable logistics. We compared the toxicity and efficacy of hypofractionated versus conventional fractionation external beam radiotherapy in patients with intermediate and high risk localized prostate cancer treated at Shaukat Khanum Memorial Cancer Hospital and Research Center, Lahore (SKMCH & RC). Methodology: We retrospectively conducted this study on 114 patients with prostate adenocarcinoma who underwent treatment at SKMCH & RC from 2013-2018. These patients were treated with radical radiotherapy along with hormonal therapy as per indication. Data was collected from electronic hospital system and analyzed by SPSS version 23. Result: Our study showed that out of total 114 patients, 12% (n=14) had an age range of 48-60 years, 56% (n= 64) were between 61-70 years and 32% (n= 36) were older than 71 years. Mean age was 68 years (61-75) and 93.4% had ECOG PS of 0-1. 88% of patients had stage III-IVA disease at the time of diagnosis with only 21% (n=24) with nodal involvement. Mean PSA was 33 ± 39 SD while mean GS was 7 ± 0.9 SD. 21% (n=24) had intermediate risk while 79% (n=89) were of high risk. Moreover, only 7 patients (30%) in intermediate risk group had PSA < 8 ng/mL and only two patients had GS above 7. In contrast, among high risk patients, 15 of them (19%) had PSA <8 ng/mL and 32 patients (41%) had GS above 7. 68% patients received ADT for ≤ 2 years. Furthermore, 89% (n=102) received radiotherapy with 69% of patients receiving dose of 60 Gy in 20 fractions while 31% got 70-76 Gy in 28-38 fractions. The patients who received hypofractionated dose, 14 % (n=10) developed grade 2 proctitis and 8% (n=6) developed grade 2 cystitis. In contrast, those who received conventional dose, only 3 patients developed grade 2 GI toxicity and 2 patients had grade 2 GU toxicity. 10 % patients (n=13) had biochemical failure while 12% (n=14) developed distal metastasis. 5 year overall survival for hypofractionated radiotherapy versus conventional dose was 100 % and 90% respectively with 95% CI and p= 0.3 (clinically insignificant), whereas 5 year disease free survival was 100 % and 75% for hypofractionation versus conventional EBRT respectively with 95% CI and p= 0.04 (clinically significant). Conclusion: Hypofractionated radiotherapy in patients with intermediate and high risk localized prostate cancer has better disease free survival at the expense of higher risk for proctitis and cystitis but no difference in overall survival as compared to conventional dose of radiation.