This phase III trial studies how well inguinal lymph node dissection (ILND) surgery alone or after chemotherapy with or without intensity-modulated radiation therapy works in treating patients with penile cancer that has spread to other places in the body. Surgery is used to remove the lymph nodes and may be able to cure the cancer. Drugs used in chemotherapy, such as paclitaxel, ifosfamide, and cisplatin, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Intensity-modulated radiation therapy uses high-energy x-rays to kill tumor cells and shrink tumors. It is not known whether having surgery after chemotherapy with or without radiation therapy is better than having surgery alone.

This phase III trial uses the Decipher risk score to guide therapy selection. Decipher score is based on the activity of 22 genes in prostate tumor and may predict how likely it is for recurrent prostate cancer to spread (metastasize) to other parts of the body. Decipher score in this study is used for patient selection and the two variations of treatment to be studied: intensification for higher Decipher score or de-intensification for low Decipher score. Patients with higher Decipher risk score will be assigned to the part of the study that compares the use of 6 months of the usual treatment (hormone therapy and radiation treatment) to the use of darolutamide plus the usual treatment (intensification). The purpose of this section of the study is to determine whether the additional drug can reduce the chance of cancer coming back and spreading in patients with higher Decipher score. The addition of darolutamide to the usual treatment may better control the cancer and prevent it from spreading. Alternatively, patients with low Decipher risk score will be assigned to the part of the study that compares the use of radiation treatment alone (de-intensification) to the usual approach (6 months of hormone therapy plus radiation). The purpose of this part of the study is to determine if radiation treatment alone is as effective compared to the usual treatment without affecting the chance of tumor coming back in patients with low Decipher score prostate cancer. Radiation therapy uses high energy to kill tumor cells and reduce the tumor size. Hormone therapy drugs such as darolutamide suppress or block the production or action of male hormones that play role in prostate cancer development. Effect of radiation treatment alone in patients with low Decipher score prostate cancer could be the same as the usual approach in stabilizing prostate cancer and preventing it from spreading, while avoiding the side effects associated with hormonal therapy.

This phase III trial compares the effect of radiation therapy combined with hormonal therapy versus hormonal therapy alone in treating patients with low risk, early stage breast cancer with Oncotype Dx Recurrence =< 18. Oncotype DX is a laboratory test which results in a score that is used to help predict whether breast cancer will spread to other parts of the body or come back. Radiation therapy uses high doses of radiation to kill cancer cells and shrink tumors but may result in some side effects. Hormones called estrogen and progesterone may contribute to the growth of breast tumor cells. Hormone therapy, also called endocrine therapy, may stop the growth of tumor cells by blocking or removing these hormones. This clinical trial may help researchers understand if patients with low-risk, early stage breast cancer who have Oncotype recurrence score of =< 18 can safely omit radiation therapy and only be treated with hormonal therapy without losing any radiation treatment benefit.

This phase II trial studies how well lower-dose chemotherapy plus radiation (chemoradiation) therapy works in comparison to standard-dose chemoradiation in treating patients with early-stage anal cancer. Drugs used in chemotherapy, such as mitomycin, fluorouracil, and capecitabine, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Radiation therapy uses high-energy x-rays to kill tumor cells and shrink tumors. Giving chemotherapy with radiation therapy may kill more tumor cells. This study may help doctors find out if lower-dose chemoradiation is as effective and has fewer side effects than standard-dose chemoradiation, which is the usual approach for treatment of this cancer type.

This phase II trial studies the effect of pembrolizumab alone compared to the usual approach (chemotherapy [cisplatin and carboplatin] plus radiation therapy) after surgery in treating patients with head and neck squamous cell carcinoma that has come back (recurrent) or patients with a second head and neck cancer that is not from metastasis (primary). Radiation therapy uses high energy radiation or protons to kill tumor cells and shrink tumors. Cisplatin is in a class of medications known as platinum-containing compounds. It works by killing, stopping or slowing the growth of cancer cells. Carboplatin is also in a class of medications known as platinum-containing compounds. It works in a way similar to the anticancer drug cisplatin, but may be better tolerated than cisplatin. Carboplatin works by killing, stopping or slowing the growth of cancer cells. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer and may interfere with the ability of tumor cells to grow and spread. Giving pembrolizumab alone after surgery may work better than the usual approach in shrinking recurrent or primary head and neck squamous cell carcinoma.

This phase I/II trial studies the side effects, safety, and effectiveness of low dose radiation to the entire body (total body irradiation [TBI]) and higher dose radiation to known areas of cancer (hypofractionated radiation therapy [H-RT]) combined with atezolizumab and chemotherapy (carboplatin & etoposide) in treating patients with small cell lung cancer that has spread to disease sites outside of the lung (extensive stage). Extensive stage disease has historically been treated with chemotherapy alone with consideration of chest (thoracic) radiation therapy for those with response to chemotherapy, as well as consideration of preventative radiation therapy to the head (prophylactic cranial irradiation). Emerging evidence supports the synergistic interactions between immunotherapy and radiation therapy. Immunotherapy with monoclonal antibodies, such as atezolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Carboplatin is in a class of medications known as platinum-containing compounds. It works in a way similar to the anticancer drug cisplatin, but may be better tolerated than cisplatin. Carboplatin works by killing, stopping or slowing the growth of tumor cells. Etoposide is in a class of medications known as podophyllotoxin derivatives. It blocks a certain enzyme needed for cell division and DNA repair and may kill tumor cells. Combining TBI and H-RT with atezolizumab and chemotherapy may improve response to treatment.

This trial collects data on response to low-dose skin electron therapy in patients with stage IB-IIIA mycosis fungoides that does not respond to treatment (refractory) or has come back (relapsed). Collecting data on patient's response to therapy, both in terms of changes in the skin and in terms of quality of life following treatment, may help doctors better predict response to therapy.

This phase II trial tests whether reduced dose radiation therapy after transoral robotic surgery works in treating patients with human papillomavirus (HPV)-positive oropharyngeal cancer. HPV positive oropharyngeal cancer has a better prognosis than oropharyngeal cancer not caused by HPV. A standard of care treatment for HPV positive oropharyngeal cancer is transoral robotic surgery followed by radiation therapy. However, this treatment is associated with many long-term side effects including difficulty swallowing. Radiation therapy uses high energy rays to kill tumor cells and shrink tumors. Giving reduced dose radiation therapy after transoral robotic surgery may improve swallowing outcomes and quality of life compared to standard of care dose radiation therapy after transoral robotic surgery.