Authors: Emily Brown, Future Science Group
Below you will find summaries of some of the key data presented this week at the 58th Annual Meeting of the American Society for Radiation Oncology (ASTRO16). What are your thoughts on the findings presented at this meeting? Leave us a comment below and let us know.
Comparable outcomes and QoL with hypofractionated vs conventional radiation therapy in low-risk prostate cancer
A study presented in the plenary session of the ASTRO 16 meeting investigated quality of life (QoL) in low-risk prostate cancer patients up to 1 year after being treated with hypofractionated radiation therapy (RT) compared with tradition RT.
Conventional RT is typically given in 40–45 fractions over the course of approximately 8–9 weeks; in this study, hypofractionated RT was given in larger doses of 28 fractions over 5–6 weeks. Those who received hypofractionated RT reported the same urinary and sexual QoL compared with those who had traditional RT.
“For low-risk prostate cancer patients who do decide they want to be treated, this study demonstrates that hypofractionated (or abbreviated) radiation therapy over 5–6 weeks is a very reasonable and viable option compared to the conventional course of 8–9 weeks,” commented senior author Benjamin Movsas (Henry Ford Hospital; MI, USA).
Stereotactic radiosurgery data indicate improved local control for brain metastases
Stereotactic radiosurgery (SRS) utilized for the treatment of brain metastases was found to decrease the rate of local recurrence of lesions following resection. However, no significant difference was noted in terms of overall survival (OS) or distant brain metastases, when compared with observation alone following surgical resection of brain metastases.
Specifically, 132 patients with 1–3 brain metastases were randomly assigned to one of two arms, either SRS to the surgical cavity (SRS-cav, n = 63) or observation alone (OBS, n = 65).
SRS significantly reduced local recurrence of the resected tumor. At 6 months following treatment, local control (LC) rates were 83% for the SRS-cav group and 57% for the OBS group. At 12 months follow-up, the LC rates were 72% for the SRS-cav group, compared with 45% for the OBS group.
Although these data indicate that LC was improved with SRS, there were no differences between treatment arms for regional recurrence, OS or time to whole-brain radiation therapy.
“Our research shows that radiosurgery in this patient cohort does reduce the incidence of local recurrence, although the findings for overall brain control, OS and time until whole-brain radiation therapy limit our ability to conclude an obvious clinical benefit,” explained lead author Anita Mahajan of MD Anderson.
Improved patient-reported side effects in gynecological malignancies with intensity-modulated radiation therapy
Women with cervical and endometrial cancer reported fewer gastrointestinal (GI) and genitourinary (GU) side effects and experienced better QoL when treated with intensity-modulated radiation therapy (IMRT) compared with conventional RT.
This multicenter, international study included 278 patients who received pelvic RT postoperatively, randomized to receive either standard RT or IMRT. GI and GU side effects along with QoL were measured via multiple patient questionnaires.
Patients in the IMRT arm experienced significantly fewer bowel-related toxicities than patients who received standard RT, and also experienced fewer high-level adverse events following treatment, including less diarrhea and fecal incontinence.
Urinary side effects at 5 weeks from treatment start were also less prevalent among patients who received IMRT. Overall the IMRT regime negatively impacted patients’ QOL less substantially than the conventional RT regime.
“Many radiation oncologists already use IMRT for women undergoing pelvic radiation, but this research provides data that using IMRT, which is a more resource intensive treatment, makes a real difference to patients receiving radiation therapy to the pelvic area,” commented lead author Ann H Klopp (University of Texas MD Anderson Cancer Center, TX, USA). “When performed by an experienced radiation oncology team, IMRT reduces the risk of short-term bowel and bladder side effects for patients with endometrial and cervical cancer.”
Hypofractionated radiation therapy can accelerate treatment in poor performance status lung cancer patients
Hypofractionated RT results in similar OS and progression-free survival (PFS) rates, limited severe side effects and shorter treatment times when compared with conventional RT in individuals with stage II and III non-small-cell lung cancer (NSCLC) unable to receive standard treatments.
The study enrolled patients from 15 centers based in Texas and this interim analysis included 60 patients, with an average age of 68 years. In total, 53 of these individuals presented with stage III NSCLC, and seven patients presented with stage II disease.
Individuals were randomized to receive either conventional RT (n = 28 patients) 60–66 Gy over the course of 30–33 treatment sessions, or hypofractionated RT group (n = 32 patients) 60 Gy over the course of 15 treatment sessions.
While no significant difference in terms of OS or PFS was found between the two groups at 24 months, a difference in side effects was identified between the two treatment arms at interim analysis. Individuals who received the course of hypofractionated RT experienced fewer grade 3 toxicities (10 for conventional RT vs. six for hypofractionated RT) and a lower rate of death from hypoxia (two for conventional RT vs. one for hypofractionated RT).