Sen. John McCain will return to Washington D.C. next week as Congress comes back to work after its August recess.

McCain, who revealed he was diagnosed with glioblastoma, an aggressive form of brain cancer, in July, started undergoing chemotherapy earlier this month, his daughter Meghan McCain said. The 81-year-old Arizona senator had previously said he planned to return to D.C. at the end of August.

“Senator McCain will return to the U.S. Senate next week as Congress begins a new legislative session and looks forward to continuing his work for the people of Arizona and the nation,” read a statement from his office.

Just days following his cancer diagnosis, McCain flew back to D.C. to cast the deciding vote against Republicans’ “skinny repeal” for the Affordable Care Act. McCain joined two Republicans, Maine Sen. Susan Collins and Alaska Sen. Lisa Murkowski, in voting against the bill. The measure failed 51-49 in a massive defeat for Senate Majority Leader Mitch McConnell.

Get our Politics Newsletter. The headlines out of Washington never seem to slow. Subscribe to The D.C. Brief to make sense of what matters most. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Write to Mahita Gajanan at mahita.gajanan@time.com.