New diagnosed with a slow growing lung Cancer in my upper right lobe.

Hi Petsin here I am 68 years  and counting  I had a CT scan done in December 2023 it showed a small nodule 6mm in my upper lobe of my right lung I had another scan done in November 2024 and the nodule had grown to 14mm I was told it was most likely a slow growing cancer . I was referred to a thoracic surgeon who said again that it was slow growing cancer ,they said they could do surgery to remove a part of the lobe .How can they be sure it' is cancer without doing a biopsy or other tests ?  I am a cancer survivor from prostate cancer which I had treatment for just over 3 years ago Radiotherapy and Hormone treatment. I was very lucky they had caught it early A month after getting the all clear I had to have an emergency operation for a Abdominal aortic aneurysm repair. Now I have the worry of possible lung cancer .