Treatment Innovations in Rectal, Lung and Brain Cancers

A theme among the science coming out of this year’s American Society of Clinical Oncology Annual Meeting is optimizing therapy to improve care and quality of life for patients. This could mean de-escalating therapy when it is not needed or using different types of therapy to target a specific genetic marker.

Eliminating Radiation for Some Rectal Cancer Patients
To decrease the risk of pelvic recurrence, radiation has been the standard curative treatment for patients with locally advanced rectal cancer prior to surgery for the past 30 years. Patients receive five and a half weeks of radiation in conjunction with radiosensitizing chemotherapy, followed by a recovery period before surgery and adjuvant chemotherapy.

Dr. Sarah Hoffe, Section Head, Gastrointestinal Radiation Oncology

But new data from the PROSPECT phase 3 clinical trial suggests radiation might not be necessary for all patients. The study randomized 1,128 patients into two groups. One received the standard treatment protocol. The second received six cycles of FOLFOX chemotherapy, followed by restaging of the cancer.  If the tumor decreased in size by more than 20%, patients went on to surgery without radiation. Results showed that only 53 of the 585 patients in the FOLFOX arm required radiation before surgery, suggesting that chemotherapy alone could be a possible new treatment regimen for those patients whose disease responds favorably to treatment. 

“The findings from this study could be practice changing. By selecting only those patients for pelvic radiation who don’t respond well to initial chemotherapy, we could significantly decrease the rate of long term toxicities we see from pelvic radiation, such as infertility, impaired bowel/bladder/sexual function, increased risk of pelvic fracture and premature menopause,” said Dr. Sarah Hoffe, section head of Gastrointestinal Radiation Oncology at Moffitt Cancer Center.

Precision Medicine Could Be Game Changer for Non-Small Cell Lung Cancer

Dr. Eric Haura, Associate Center Director, Clinical Science

There are 1.8 million lung cancer deaths each year globally, and 80% of those are diagnosed with non-small cell lung cancer. It is an alarming statistic, but targeted therapy could be an option for this patient population.

Results from the ADAURA international phase 3 trial show adjuvant osimertinib, a targeted cancer drug, has a statistically significant and clinically meaningful overall survival benefit in patients with EGFR-mutated stage 1B–3A non-small cell lung cancer after complete tumor resection. The study randomized 682 patients into an osimertinib arm or placebo arm. The five year overall survival rate for patients receiving osimertinib was 88%, compared to 78% for placebo.

“It is gratifying to see the promise of precision medicine now realized in earlier stages of lung cancer demonstrated with longer survival in this group of patients,” said Dr. Eric Haura, associate center director of Clinical Science at Moffitt.

New Treatment Option for Brain Tumors
Gliomas are slow growing brain tumors that are difficult to treat. Surgery and chemotherapy are not curative and are often associated with short and long term toxicities. But a new more targeted treatment approach is proving beneficial for this patient population.

Dr. Peter Forsyth, Chair, Neuro-Oncology Department

The target is isocitrate dehydrogenase, a metabolic enzyme. Mutations in isocitrate dehydrogenase 1 or 2 occur in roughly 80% and 4% of grade 2 gliomas, respectively. The INDIGO trial evaluated the use of vorasidenib, an oral brain-penetrant, inhibitor of isocitrate dehydrogenase 1/2 in this population. Investigators randomized 331 patients into vorasidenib and placebo. Interim data analysis of the phase 3 trial showed median progression free survival at 27.7 months for the vorasidenib group compared to 11.1 months in the placebo group.

“This is a very important study for several reasons. It builds on the discovery of these neoformic mutations, which was a major discovery in glioma biology. It’s also the first randomized study using a targeted approach to treating low-grade gliomas,” said Dr. Peter Forsyth, chair of Moffitt’s Neuro-Oncology Department. “This offers another treatment option for patients with low-grade gliomas and opens up this new avenue of treatment.”

📰News from #ASCO23: Now that cancer txs have improved, researchers are starting to ask different Qs. Instead of asking how cancer therapy can be intensified, they are asking if there are elements of successful txs that can be eliminated to provide pts w better QOL says @ASCOPres https://t.co/vdMW7lL5R0

— ASCO (@ASCO) June 4, 2023