Chemotherapy for melanoma has limited effectiveness compared to newer treatments. The most commonly used chemotherapy drug produces tumor shrinkage in only 10% to 20% of patients, and those responses typically last about 5 to 6 months. No chemotherapy regimen has ever been shown to extend overall survival in randomized trials. For this reason, chemotherapy is now considered a palliative option, used mainly when immunotherapy and targeted therapy are not suitable or have stopped working.
Response Rates for Standard Chemotherapy
The backbone of melanoma chemotherapy for decades has been dacarbazine, an intravenous drug approved in 1970. In phase III trials, it achieves an objective response rate of 10% to 20%, meaning that only one or two out of every ten patients see meaningful tumor shrinkage. Complete responses, where all detectable cancer disappears, occur in roughly 5% of patients. Even when tumors do respond, the benefit is short-lived, with a median response duration of about 5 to 6 months before the cancer begins growing again.
A related oral drug called temozolomide performs similarly to dacarbazine in clinical trials but has one practical advantage: it crosses into the brain. For patients with melanoma that has spread to the brain, temozolomide is sometimes preferred because dacarbazine does not reach brain tissue effectively. It also comes as a pill, which can spare patients frequent trips to infusion centers. That said, the number of brain metastases that actually shrink with temozolomide alone remains small.
Combination chemotherapy regimens have also been tested extensively. Carboplatin paired with paclitaxel, for instance, produces response rates around 18%, which is roughly comparable to dacarbazine alone. Despite decades of effort to find more potent chemotherapy combinations, none have proven to extend survival beyond what a single agent achieves.
Why Higher Response Rates Haven’t Meant Longer Survival
One of the more frustrating findings in melanoma research involves biochemotherapy, which combines traditional chemotherapy drugs with older immune-stimulating agents like interferon and interleukin-2. A meta-analysis of 18 trials involving over 2,600 patients found that biochemotherapy clearly improved response rates compared to chemotherapy alone. More tumors shrank, and more patients achieved complete responses. Yet this did not translate into a survival benefit. The cancer responded initially but came back aggressively, leaving patients no better off in the long run.
This pattern highlights a key limitation of chemotherapy in melanoma. The cancer cells that survive treatment tend to be resistant, and regrowth is often rapid. Chemotherapy can reduce tumor burden temporarily, which may relieve symptoms like pain or pressure from large tumors, but it rarely changes the overall trajectory of the disease.
How Immunotherapy Changed the Landscape
Before 2011, when the first checkpoint inhibitor was approved, the five-year survival rate for stage IV melanoma was less than 10%. Chemotherapy was essentially the only systemic option, and outcomes were grim, with median overall survival ranging from 4 to 12 months.
The contrast with modern immunotherapy is stark. In the landmark CheckMate 066 trial, 39% of patients treated with nivolumab (a checkpoint inhibitor) were alive at the time of analysis compared to 17% of those who received dacarbazine. Both dacarbazine and another older chemotherapy approach were used as comparison arms in the trials that led to approval of newer drugs, and in every case, they performed worse. Five-year survival rates with immunotherapy are now roughly double what chemotherapy ever achieved.
For patients whose melanoma carries a specific genetic change called a BRAF mutation (present in about half of all melanomas), targeted therapy with drugs that block that mutation also outperforms chemotherapy. In a head-to-head trial, vemurafenib showed superior overall survival compared to dacarbazine.
Chemotherapy After Surgery
In the adjuvant setting, where treatment is given after surgery to reduce the risk of recurrence, chemotherapy has no established role in melanoma. The treatments that have proven effective at prolonging recurrence-free survival are checkpoint inhibitors (like pembrolizumab and nivolumab) and, for BRAF-mutated melanoma, targeted therapy combinations. These drugs have been approved for stage III melanoma based on large randomized trials, and pembrolizumab has also been approved for earlier-stage disease (stage IIB and IIC) based on similar evidence. Chemotherapy was never shown to meaningfully reduce relapse risk in these settings.
When Chemotherapy Is Still Used
Current treatment guidelines from the National Cancer Institute list chemotherapy under palliative therapy for advanced melanoma. It sits below immunotherapy and targeted therapy in the treatment hierarchy, reserved for patients who have already tried those options or who cannot tolerate them. Some patients have conditions that make immunotherapy risky, such as severe autoimmune diseases or organ transplants requiring immune-suppressing medications. For these patients, chemotherapy remains a fallback.
The side effects of dacarbazine are dominated by nausea and drops in blood cell counts. In studies, severe decreases in white blood cells and platelets occurred in roughly one in four patients. These side effects are manageable in most cases but add to the burden of a treatment with modest benefits.
A Small Group of Long-Term Survivors
One finding worth noting comes from a long-term follow-up study of patients treated with dacarbazine or temozolomide. With a median follow-up of nearly 12 years, the five-year progression-free survival rate was 16%, and the survival curve flattened after that point. This suggests that a small minority of patients treated with chemotherapy alone achieved durable, possibly permanent responses. Researchers interpret the plateau as evidence that roughly one in six responders may have been effectively cured, though the overall numbers remain far lower than what immunotherapy now achieves.
This finding is a reminder that melanoma biology varies widely between patients. A small subset responds exceptionally well even to older treatments, likely because of favorable immune characteristics that chemotherapy alone was enough to tip in the right direction. For the vast majority, however, chemotherapy offers temporary symptom control at best.