Radiologist Questions Radiologist

How long does it take for lung cancer to shrink after radiation?

I will have radiation therapy for lung cancer. How long does it take for lung cancer to shrink after radiation?

3 Answers

You are asking about the ability to predict if lung cancer will shrink in response to radiation. This has been a question that is being asked by patients and physicians for a long time. The answer is that it is usually not possible to predict the response rate of any cancer to radiation or other treatments except by using the treatment and then assessing the growth pattern of the tumor after treatment.

A usual method that is used by oncologists is to treat large numbers of patients for one to two months and then reassess by X-rays and assess the size of the tumor nodules. This is done for both radiation and chemotherapy. In lung cancer the histology of the tumor is important. Small cell lung cancer is often more radiation and chemotherapy sensitive than the more common non-small cell lung cancer.

Depending on the histology surgery is often used as a primary treatment. Sometimes chemotherapy and radiation are used together as combination therapy. In 2021 immunotherapy has become important. The best approach might be to enroll in a clinical trial comparing or using a new treatment approach to improve the long-term control of each type of tumor.

A good review of approaches to treatment of lung cancer was published by Amit Dos, Marcus Bell and John D MInna in Seminars in Radiation Oncology July 2010 pages 149-155. This is a summary of research efforts using molecular biology to predict the response rate of tumors to radiation. Survivals of various patient groups are compared.

Good Luck.
We usually see some improvement in 2-4 weeks.
The typical treatment is 5 weeks of radiation concurrent oral chemotherapy in the neo adjuvant setting. In the adjuvant setting, 6 weeks of radiation concurrent with chemotherapy.
I hope your friend will do well.