Many treatment options for cancer exist. The primary ones include surgery, chemotherapy, radiation therapy, hormonal therapy, targeted therapy and palliative care. Which treatments are used depends on the type, location and grade of the cancer as well as the patient's health and preferences. The treatment intent may or may not be curative.

Chemotherapy is the treatment of cancer with one or more cytotoxic anti-neoplastic drugs (chemotherapeutic agents) as part of a standardized regimen. The term encompasses a variety of drugs, which are divided into broad categories such as alkylating agents and antimetabolites. Traditional chemotherapeutic agents act by killing cells that divide rapidly, a critical property of most cancer cells.

Targeted therapy is a form of chemotherapy that targets specific molecular differences between cancer and normal cells. The first targeted therapies blocked the estrogen receptor molecule, inhibiting the growth of breast cancer. Another common example is the class of Bcr-Abl inhibitors, which are used to treat chronic myelogenous leukemia (CML). Currently, targeted therapies exist for breast cancer, multiple myeloma, lymphoma, prostate cancer, melanoma and other cancers.

The efficacy of chemotherapy depends on the type of cancer and the stage. In combination with surgery, chemotherapy has proven useful in cancer types including breast cancer, colorectal cancer, pancreatic cancer, osteogenic sarcoma, testicular cancer, ovarian cancer and certain lung cancers. Chemotherapy is curative for some cancers, such as some leukemias, ineffective in some brain tumors, and needless in others, such as most non-melanoma skin cancers. The effectiveness of chemotherapy is often limited by its toxicity to other tissues in the body. Even when chemotherapy does not provide a permanent cure, it may be useful to reduce symptoms such as pain or to reduce the size of an inoperable tumor in the hope that surgery will become possible in the future.

Treatment of metastatic breast cancer is currently an active area of research. Several medications are in development or in phase I/II trials. Typically new medications and treatments are first tested in metastatic cancer before trials in primary cancer are attempted.

Another area of research is finding combination treatments which provide higher efficacy with reduced toxicity and side effects.

Experimental medications:

- sorafenib a combined Tyrosine protein kinases inhibitor.

Some patients with metastatic breast cancer opt to try alternative therapies such as vitamin therapy, homeopathic treatments, a macrobiotic diet, chiropractic or acupuncture. There is no evidence that any of these therapies are effective; they may be harmful, either because patients pass up effective conventional therapies such as chemotherapy or anti-estrogen therapy in favor of alternative treatments, or because the treatments themselves are harmful (as in the case of apricot-pit therapy—which exposes the patient to cyanide—or in chiropractic, which can be dangerous to patients with cancer metastatic to the spinal bones or spinal cord. A macrobiotic diet is neither effective nor safe as it could hypothetically induce weight loss due to severe dietary restriction. There is limited evidence that acupuncture might relive pain in cancer patients, but data so far is insufficient to recommend its use outside of clinical trials.

There is free peer support and an online platform to interact with others going through various therapies, including Abraxane.

In breast cancer survivors, it is recommended to first consider non-hormonal options for menopausal effects, such as bisphosphonates or selective estrogen receptor modulators (SERMs) for osteoporosis, and vaginal estrogen for local symptoms. Observational studies of systemic hormone replacement therapy after breast cancer are generally reassuring. If hormone replacement is necessary after breast cancer, estrogen-only therapy or estrogen therapy with an intrauterine device with progestogen may be safer options than combined systemic therapy.

Drugs used after and in addition to surgery are called adjuvant therapy. Chemotherapy or other types of therapy prior to surgery are called neoadjuvant therapy. Aspirin may reduce mortality from breast cancer.

There are currently three main groups of medications used for adjuvant breast cancer treatment: hormone-blocking agents, chemotherapy, and monoclonal antibodies.

Hormone blocking therapy

Chemotherapy

Monoclonal antibodies

Several drugs that target molecular pathways in lung cancer are available, especially for the treatment of advanced disease. Erlotinib, gefitinib and afatinib inhibit tyrosine kinase at the epidermal growth factor receptor. Denosumab is a monoclonal antibody directed against receptor activator of nuclear factor kappa-B ligand. It may be useful in the treatment of bone metastases.

Several treatments can be administered via bronchoscopy for the management of airway obstruction or bleeding. If an airway becomes obstructed by cancer growth, options include rigid bronchoscopy, balloon bronchoplasty, stenting, and microdebridement. Laser photosection involves the delivery of laser light inside the airway via a bronchoscope to remove the obstructing tumor.

Palliative care is medical care which focuses on treatment of symptoms from serious illness, like cancer, and improving quality of life. Palliative care is recommended for any person who has advanced colon cancer or has significant symptoms.

Involvement of palliative care may be beneficial to improve the quality of life for both the person and his or her family, by improving symptoms, anxiety and preventing admissions to the hospital.

In people with incurable colorectal cancer, palliative care can consist of procedures that relieve symptoms or complications from the cancer but do not attempt to cure the underlying cancer, thereby improving quality of life. Surgical options may include non-curative surgical removal of some of the cancer tissue, bypassing part of the intestines, or stent placement. These procedures can be considered to improve symptoms and reduce complications such as bleeding from the tumor, abdominal pain and intestinal obstruction. Non-operative methods of symptomatic treatment include radiation therapy to decrease tumor size as well as pain medications.

While a combination of radiation and chemotherapy may be useful for rectal cancer, its use in colon cancer is not routine due to the sensitivity of the bowels to radiation. Just as for chemotherapy, radiotherapy can be used in the neoadjuvant and adjuvant setting for some stages of rectal cancer.

Most hormone dependent cancers become resistant to treatment after one to three years and resume growth despite hormone therapy. Previously considered "hormone-refractory prostate cancer" or "androgen-independent prostate cancer", the term castration-resistant has replaced "hormone refractory" because while they are no longer responsive to castration treatment (reduction of available androgen/testosterone/DHT by chemical or surgical means), these cancers still show reliance upon hormones for androgen receptor activation.

The cancer chemotherapic docetaxel has been used as treatment for CRPC with a median survival benefit of 2 to 3 months. A second-line chemotherapy treatment is cabazitaxel. A combination of bevacizumab, docetaxel, thalidomide and prednisone appears effective in the treatment of CRPC.

The immunotherapy treatment with sipuleucel-T in CRPC increases survival by 4 months. The second line hormonal therapy abiraterone increases survival by 4.6 months when compared to placebo. Enzalutamide is another second line hormonal agent with a 5-month survival advantage over placebo. Both abiraterone and enzalutamide are currently being tested in clinical trials in those with CRPC who have not previously received chemotherapy.

Only a subset of people respond to androgen signaling blocking drugs and certain cells with characteristics resembling stem cells remain unaffected. Therefore, the desire to improve outcome of people with CRPC has resulted in the claims of increasing doses further or combination therapy with synergistic androgen signaling blocking agents. But even these combination will not affect stem-like cells that do not exhibit androgen signaling. It is possible that for further advances, a combination of androgen signaling blocking agent with stem-like cell directed differentiation therapy drug would prove ideal.

Treatment options vary and depend on the type and stage of cancer. Common treatments include surgery, chemotherapy, radiation therapy, amputation, and immunotherapy. A combination of therapies may be used. Knowledge and treatment of cancer have increased significantly in the past three decades. Survival rates have also increased due to the increase prevalence of canine cancer treatment centers and breakthroughs in targeted drug development. Canine cancer treatment has become an accepted clinical practice and access to treatment for owners has widely expanded recently. Cancer-targeting drugs most commonly function to inhibit excessive cell proliferation by attacking the replicating cells. However, there is still a prevalent pharmacy gap in veterinary oncology.

There is one canine tumor vaccine approved by the USDA, for preventing canine melanoma. The Oncept vaccine activates T-cell responses and antibodies against tumor-specific tyrosinase proteins. There is limited information about canine tumor antigens, which is the reason for the lack of tumor-specific vaccines and immunotherapy treatment plans for dogs.

Success of treatment depends on the form and extent of the cancer and the aggressiveness of the therapy. Early detection offers the best chance for successful treatment. The heterogeneity of tumors makes drug development increasingly complex, especially as new causes are discovered. No cure for cancer in canines exist.

Some dog owners opt for no treatment of the cancer at all, in which case palliative care, including pain relief, may be offered. Regardless of how treatment proceeds following a diagnosis, the quality of life of the pet is an important consideration. In cases where the cancer is not curable, there are still many things which can be done to alleviate the dog's pain. Good nutrition and care from the dog's owner can greatly enhance quality of life.

If ovarian cancer recurs, it is considered partially platinum-sensitive or platinum-resistant, based on the time since the last recurrence treated with platins: partially platinum-sensitive cancers recurred 6–12 months after last treatment, and platinum-resistant cancers have an interval of less than 6 months. Second-line chemotherapy can be given after the cancer becomes symptomatic, because no difference in survival is seen between treating asymptomatic (elevated CA-125) and symptomatic recurrences.

For platinum-sensitive tumors, platins are the drugs of choice for second-line chemotherapy, in combination with other cytotoxic agents. Regimens include carboplatin combined with pegylated liposomal doxorubicin, gemcitabine, or paclitaxel. Carboplatin-doublet therapy can be combined with paclitaxel for increased efficacy in some cases. Another potential adjuvant therapy for platinum-sensitive recurrences is olaparib, which may improve progression-free survival but has not been shown to improve overall survival. (Olaparib, a PARP inhibitor, was approved by the US FDA for use in BRCA-associated ovarian cancer that had previously been treated with chemotherapy.) For recurrent germ cell tumors, an additional 4 cycles of BEP chemotherapy is the first-line treatment for those tho have been treated with surgery or platins.

If the tumor is determined to be platinum-resistant, vincristine, dactinomycin, and cyclophosphamide (VAC) or some combination of paclitaxel, gemcitabine, and oxaliplatin may be used as a second-line therapy.

For platinum-resistant tumors, there are no high-efficacy chemotherapy options. Single-drug regimens (doxorubicin or topotecan) do not have high response rates, but single-drug regimens of topotecan, pegylated liposomal doxorubicin, or gemcitabine are used in some cases. Topotecan cannot be used in people with an intestinal blockage. Paclitaxel used alone is another possible regimen, or it may be combined with liposomal doxorubicin, gemcitabine, cisplatin, topotecan, etoposide, or cyclophosphamide. ( See also Palliative care below.)

Adjuvant chemotherapy is a recent innovation, consisting of some combination of paclitaxel (or other taxanes like docetaxel), doxorubicin (and other anthracyclines), and platins (particularly cisplatin and carboplatin). Adjuvant chemotherapy has been found to increase survival in stage III and IV cancer more than added radiotherapy. Mutations in mismatch repair genes, like those found in Lynch syndrome, can lead to resistance against platins, meaning that chemotherapy with platins is ineffective in people with these mutations. Side effects of chemotherapy are common. These include hair loss, low neutrophil levels in the blood, and gastrointestinal problems.

In cases where surgery is not indicated, palliative chemotherapy is an option; higher-dose chemotherapy is associated with longer survival. Palliative chemotherapy, particularly using capecitabine and gemcitabine, is also often used to treat recurrent endometrial cancer.

Palliative care is medical care which focuses on treatment of symptoms of serious illness, like cancer, and improving quality of life. One of the goals of treatment in palliative care is symptom control rather than a cure of the underlying cancer. Pain is common in metastatic prostate cancer, and cancer pain related to bone metastases can be treated with bisphosphonates, medications such as opioids, and palliative radiation therapy to known metastases. Spinal cord compression can occur with metastases to the spine and can be treated with steroids, surgery, or radiation therapy. Other symptoms that can be addressed through palliative care include fatigue, delirium, lymphedema in the scrotum or penis, nausea, vomiting, and weight loss.

Hormone therapies are a topic of current research in ovarian cancer, particularly, the value of certain medications used to treat breast cancer. These include tamoxifen, letrozole, and anastrozole. Preliminary studies have showed a benefit for tamoxifen in a small number of people with advanced ovarian cancer. Letrozole may help to slow or stop growth of estrogen receptor positive ovarian cancer. Anastrozole is being investigated in postmenopausal people with estrogen receptor-positive cancer.

Research into mitigating side effects of ovarian cancer treatment is also ongoing. Radiation fibrosis, the formation of scar tissue in an area treated with radiation, may be relieved with hyperbaric oxygen therapy, but research has not been completed in this area. Treatment of ovarian cancer may also cause people to experience psychiatric difficulties, including depression. Research is ongoing to determine how counseling and psychotherapy can help people who have ovarian cancer during treatment.

There are a number of possible additional therapies. Surgery can be followed by radiation therapy and/or chemotherapy in cases of high-risk or high-grade cancers. This is called adjuvant therapy.

Standard treatment is surgery with adjuvant chemotherapy and radiotherapy. As a variation, neoadjuvant chemotherapy is very frequently used for triple-negative breast cancers. This allows for a higher rate of breast-conserving surgeries and by evaluating the response to the chemotherapy gives important clues about the individual responsiveness of the particular cancer to chemotherapy.

In addition to chemotherapy, an additive called Didox can be added to aid in the reduction of drug resistance and further treatment efforts. Didox is used to inhibit ribonucleotide reductase M2 (RRM2) which contributes to the cells resistance of the chemotherapy treatment resulting in a large number of relapse (Wilson 2016). RRM2 is upregulated within these specific Triple Negative cancer cells leading to a higher rate of drug resistance and inability to slow or stop the tumor progression which leads to more aggressive forms of triple negative breast cancer that are often fatal (Wilson 2016).

TNBCs are generally very susceptible to chemotherapy. In some cases, however, early complete response does not correlate with overall survival. This makes it particularly complicated to find the optimal chemotherapy. Adding a taxane to the chemotherapy appears to improve outcome substantially.

"BRCA1"-related triple-negative breast cancer appear to be particularly susceptible to chemotherapy including platinum-based agents and taxanes.

Although mutations in single genes were not individually predictive, TNBC tumors bearing mutations in genes involved in the androgen receptor (AR) and FOXA1 pathways were much more sensitive to chemotherapy. Mutations in the AR/FOXA1 pathway provide a novel marker for identifying chemosensitive TNBC patients who may benefit from current standard-of-care chemotherapy regimens. Mutations that lowered the levels of functional BRCA1 or BRCA2 RNA were associated with significantly better survival outcomes. This BRCA deficience signature define a new, highly chemosensitive subtype of TNBC. BRCA-deficient TNBC tumors have a higher rate of clonal mutation burden, defined as more clonal tumors with a higher number of mutations per clone, and are also associated with a higher level of immune activation, which may explain their greater chemosensitivity.

Chemotherapeutic options include:

- Cyclophosphamide plus methotrexate plus fluorouracil (CMF).

- Cyclophosphamide plus doxorubicin plus fluorouracil (CAF).

- Trastuzumab (monoclonal antibody therapy).

Hormonal options include:

- Orchiectomy.

- Gonadotropin hormone releasing hormone agonist (GNRH agonist) with or without total androgen blockage (anti-androgen).

- Tamoxifen for estrogen receptor–positive patients.

- Progesterone.

- Aromatase inhibitors.

Radiation therapy is the most common form of treatment. There are different forms of radiation therapy, including 3D conformal radiation therapy, intensity-modulated radiation therapy, particle beam therapy and brachytherapy, which are commonly used in the treatments of cancers of the head and neck. Most people with head and neck cancer who are treated in the United States and Europe are treated with intensity-modulated radiation therapy using high energy photons. At higher doses, head and neck radiation is associated with thyroid dysfunction and pituitary axis dysfunction.

Chemotherapy in throat cancer is not generally used to "cure" the cancer as such. Instead, it is used to provide an inhospitable environment for metastases so that they will not establish in other parts of the body. Typical chemotherapy agents are a combination of paclitaxel and carboplatin. Cetuximab is also used in the treatment of throat cancer.

Docetaxel-based chemotherapy has shown a very good response in locally advanced head and neck cancer. Docetaxel is the only taxane approved by US FDA for head and neck cancer, in combination with cisplatin and fluorouracil for the induction treatment of inoperable, locally advanced squamous cell carcinoma of the head and neck.

While not specifically a chemotherapy, amifostine is often administered intravenously by a chemotherapy clinic prior to IMRT radiotherapy sessions. Amifostine protects the gums and salivary glands from the effects of radiation.

Superficial tumors (those not entering the muscle layer) can be "shaved off" using an electrocautery device attached to a cystoscope, which in that case is called a resectoscope. The procedure is called transurethral resection of bladder tumor—TURBT—and serves primarily for pathological staging. In case of non-muscle invasive bladder cancer the TURBT is in itself the treatment, but in case of muscle invasive cancer, the procedure is insufficient for final treatment.

Immunotherapy by intravesicular delivery of Bacillus Calmette–Guérin (BCG) is also used to treat and prevent the recurrence of superficial tumors. BCG is a vaccine against tuberculosis that is prepared from attenuated (weakened) live bovine tuberculosis bacillus, Mycobacterium bovis, that has lost its virulence in humans. BCG immunotherapy is effective in up to 2/3 of the cases at this stage, and in randomized trials has been shown to be superior to standard chemotherapy. The mechanism by which BCG prevents recurrence is unknown, but the presence of bacteria in the bladder may trigger a localized immune reaction which clears residual cancer cells.

Patients whose tumors recurred after treatment with BCG are more difficult to treat. Many physicians recommend cystectomy for these patients. This recommendation is in accordance with the official guidelines of the European Association of Urologists (EAU) and the American Urological Association (AUA) However, many patients refuse to undergo this life changing operation, and prefer to try novel conservative treatment options before opting to this last radical resort. Device assisted chemotherapy is one such group of novel technologies used to treat superficial bladder cancer. These technologies use different mechanisms to facilitate the absorption and action of a chemotherapy drug instilled directly into the bladder. Another technology - electromotive drug administration (EMDA) – uses an electric current to enhance drug absorption after surgical removal of the tumor. Another technology, thermotherapy, uses radio-frequency energy to directly heat the bladder wall, which together with chemotherapy shows a synergistic effect, enhancing each other's capacity to kill tumor cells. This technology was studied by different investigators.

The use of chemotherapy to treat stomach cancer has no firmly established standard of care. Unfortunately, stomach cancer has not been particularly sensitive to these drugs, and chemotherapy, if used, has usually served to palliatively reduce the size of the tumor, relieve symptoms of the disease and increase survival time. Some drugs used in stomach cancer treatment have included: 5-FU (fluorouracil) or its analog capecitabine, BCNU (carmustine), methyl-CCNU (semustine) and doxorubicin (Adriamycin), as well as mitomycin C, and more recently cisplatin and taxotere, often using drugs in various combinations. The relative benefits of these different drugs, alone and in combination, are unclear. Clinical researchers are exploring the benefits of giving chemotherapy before surgery to shrink the tumor, or as adjuvant therapy after surgery to destroy remaining cancer cells.

Removing the tumor by either surgical resection or liver transplant can be used in the treatment of hepatoblastoma. In some cases surgery can offer a cure. Chemotherapy may be used before and after surgery and transplant.

Chemotherapy, including cisplatin, vincristine, cyclophosphamide, and doxorubicin are used for the systemic treatment of hepatoblastoma. Out of these drugs, cisplatin seems to be the most effective.

Resection is an option in cholangiocarcinoma, but less than 30% of cases of cholangiocarcinoma are resectable at diagnosis. After surgery, recurrence rates are up to 60%. Liver transplant may be used where partial resection is not an option, and adjuvant chemoradiation may benefit some cases.

60% of cholangiocarcinomas form in the perihilar region and photodynamic therapy can be used to improve quality of life and survival time in these unresectable cases. Photodynamic therapy is a novel treatment that utilitizes light activated molecules to treat the tumor. The compounds are activated in the tumor region by laser light, which causes the release of toxic reactive oxygen species, killing tumor cells.

Systemic chemotherapies such as gemcitabine and cisplatin are sometimes used in inoperable cases of cholangiocarcinoma.

Radio frequency ablation, transarterial chemoembolization and internal radiotherapy (brachytherapy) all show promise in the treatment of cholangiocarcinoma.

Radiotherapy may be used in the adjuvant setting or for palliative treatment of cholangiocarcinoma.